flood insurance study

The Federal Emergency Management Agency in Cooperation with

DuPage County, Illinois Presents:

FLOOD INSURANCE STUDY

A Report of Flood Hazards in:

DUPAGE COUNTY, ILLINOIS AND INCORPORATED AREAS

Prepared, in parts, by:

FEMA Region V Nika Engineering 536 South Clark Street 421 Mill Street Chicago, Illinois 60605 and Batavia, Illiois 60510 March 20071 7043CV000A

NOTICE TO FLOOD INSURANCE STUDY USERS

Communities participating in the National Flood Insurance Program have established repositories of flood hazard data for floodplain management and flood insurance purposes. This Flood Insurance Study (FIS) may not contain all data available within the repository. It is advisable to contact the community repository for any additional data. Part or all of this FIS may be revised and republished at any time. In addition, part of this FIS may be revised by the Letter of Map Revision process, which does not involve republication or redistribution of the FIS. It is, therefore, the responsibility of the user to consult with community officials and to check the community repository to obtain the most current FIS components.

Initial Countywide FIS Effective Date: December 4, 1985Revised Countywide FIS Date: June 16, 2004

FLOOD INSURANCE STUDY DuPAGE COUNTY, ILLINOIS

TABLE OF CONTENTS

Page # 1. INTRODUCTION 1

1.1. Purpose of Study 1 1.2. Authority and Acknowledgments 1 1.3. Coordination 5 1.4. Regional Participation and Progress 7

2. AREA STUDIED 8 2.1. Scope of Study 8 2.2. Community Description 8 2.3. Watershed Description 8

2.3.1. DesPlaines River (DP) 9 2.3.1.1. Geographical Description 9 2.3.1.2. Principal Flood Problems 9 2.3.1.3. Flood Protection Measures 11

2.3.2. DuPage River (DU) 13 2.3.2.1. Geographical Description 13 2.3.2.2. Principal Flood Problems 13 2.3.2.3. Flood Protection Measures 13

2.3.3. East Branch DuPage River (EB) 14 2.3.3.1. Geographical Description 14 2.3.3.2. Principal Flood Problems 14 2.3.3.3. Flood Protection Measures 18

2.3.4. Fox River (FR) 21 2.3.4.1. Geographical Description 21 2.3.4.2. Principal Flood Problems 21 2.3.4.3. Flood Protection Measures 22

2.3.5. Salt Creek (SC) 23 2.3.5.1. Geographical Description 23 2.3.5.2. Principal Flood Problems 23 2.3.5.3. Flood Protection Measures 25

2.3.6. Sawmill Creek (SW) 27 2.3.6.1. Geographical Description 27 2.3.6.2. Principal Flood Problems 27 2.3.6.3. Flood Protection Measures 27

2.3.7. West Branch DuPage River (WB) 29 2.3.7.1. Geographical Description 29 2.3.7.2. Principal Flood Problems 29 2.3.7.3. Flood Protection Measures 33

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TABLE OF CONTENTS - continued

3. ENGINEERING METHODS & FLOOD PLAIN MANAGEMENT APPLICATIONS 36 Note: The following subsections under ENGINEERING METHODS & FLOODPLAIN MANAGEMENT APPLICATIONS do not have page numbers and are clearly marked as tabs. Each tributary shall contain the following elements: Tributary Description, Hydrologic Analysis, Hydraulic Analysis, Flood Boundaries, Floodways and Flood Profiles. As tributaries are updated and approved, these individual tributary tabs can be quickly replaced without the additional work of updating the Table of Contents. The tabs contained herein are as follows:

3.1. DesPlaines River (DP) 3.1.1. Main Stem (DPDP) 3.1.2. Addison Creek (DPAC) 3.1.3. Bensenville Ditch (DPBD) 3.1.4. Black Partridge Creek (DPBP) 3.1.5. Crystal Creek (DPCT) 3.1.6. Flagg Creek (DPFC)

3.2.1. Lily Cache (DULC)

3.1.7. Willow Creek (DPWL) 3.2. DuPage River (DU)

3.2.2. Springbrook #2 (DUSG) 3.3. East Branch DuPage River (EB)

3.3.1. Main Stem (EBEB) 3.3.2. Armitage Creek (EBAR) 3.3.3. Army Trail Road Tributary (EBAT) 3.3.4. Crabtree Creek (EBCR) 3.3.5. Tributary #1 (EBE1) 3.3.6. Tributary #2 (EBE2) 3.3.7. Tributary #3 (EBE3) 3.3.8. Tributary #6 (EBE6) 3.3.9. Tributary #7 (EBE7) 3.3.10. Glen Crest Creek (EBGL) 3.3.11. Glen Park (EBGP) 3.3.12. Lacey Creek (EBLA) 3.3.13. Prentiss Creek (EBPR) 3.3.14. Rott Creek (EBRC) 3.3.15. St. Joseph Creek (EBSJ) 3.3.16. Swift Meadows (EBSM) 3.3.17. 22nd Street (EBTS) 3.3.18. Willoway Brook (EBWI)

3.4. Fox River (FR) 3.4.1. Brewster Creek (FRBC) 3.4.2. Indian Creek (FRIC) 3.4.3. Norton Creek (FRNC) 3.4.4. Waubansee Creek (FRWA)

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3.5. Salt Creek (SC) 3.5.1. Main Stem (SCSC) 3.5.2. Bronswood Creek (SCBW) 3.5.3. Devon Avenue Tributary (SCDA) 3.5.4. Ginger Creek (SCGC) 3.5.5. Oak Brook Tributary (SCOB) 3.5.6. Spring Brook Creek (SCSB) 3.5.7. Sugar Creek (SCSU) 3.5.8. Westwood Creek (SCWC)

3.6. Sawmill Creek (SW) 3.6.1. Sawmill Creek (SWSW) 3.6.2. Wards Creek (SWWD)

3.7. West Branch DuPage River (WB) 3.7.1. Main Stem (WBWB) 3.7.2. Cress Creek (WBCC) 3.7.3. Ferry Creek (WBFE) 3.7.4. South of Foxcroft (WBFX) 3.7.5. Klein Creek (WBKC) 3.7.6. Kress Creek (WBKR) 3.7.7. Spring Brook #1 (WBSP) 3.7.8. Steeple Run Tributary (WBSR) 3.7.9. Tributary #1 (WBW1) 3.7.10. Tributary #2 (WBW2) 3.7.11. Tributary #3 (WBW3) 3.7.12. Tributary #4 (WBW4) 3.7.13. Tributary #5 (WBW5) 3.7.14. Tributary #6 (WBW6) 3.7.15. Tributary #7 (WBW7) 3.7.16. Tributary #8 (WBW8) 3.7.17. Winfield Creek (WBWF) 3.7.18. Winding Creek (WBWG)

4. INSURANCE APPLICATION 41 4.1. Reach Determinations 41 4.2. Flood Hazard Factors 41 4.3. Flood Insurance Zones 41 4.4. Flood Insurance Rate Map Description 43

5. OTHER STUDIES 44 6. LOCATION OF DATA 46 7. REFERENCES AND BIBLIOGRAPHY 47

FIGURES Figure 1 - Floodway Schematic 40

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TABLES

Table 1 - Tributary Study Acknowledgements 2 Table 2 - Initial and Final CCO Meetings 5 Table 3 - Flagg Creek Recorded Flood Discharges 10 Table 4 - East Branch DuPage River Flood Stages at Army Trail Road 14 Table 5 - East Branch DuPage River August 1972 Recorded Flood Crests 15 Table 6 - Prentiss Creek Flood of Record Recorded Flood Crests at Route 53 17 Table 7 - Spring Brook Salt Creek Flood Stages 24 Table 8 - USGS Recorder Gage of Salt Creek at Western Springs 25 Table 9 - Winfield Creek Gage Readings for 1972 Flood Event 32 EXHIBITS (as can be found in each corresponding tributary TAB in section 3.0) Exhibit 1 - Flood Profiles Addison Creek (DPAC) Panel 01P Addison Creek Tributary No. 1 (DPAC) Panel 02P Addison Creek Tributary No. 2 (DPAC) Panel 03P Addison Creek Tributary No. 3 (DPAC) Panels 04P-05P Armitage Ditch (EBAR) Panels 30P-31P Armitage Fork (EBAR) Panel 32P Bensenville Ditch (Silver Creek) (DPBP) Panels 06P-07P Brewster Creek (FRBC) Panels 85P-86P Briarwood Ditch (SCGC) Panel 98P Bronswood Tributary (SCBW) Panels 91P-93P Crabtree Creek (EBCR) Panels 33P-35P Cress Creek (WBCC) Panel 150P Des Plaines River (DPDP) Panels 08P-09P Devon Avenue Tributary (SCDA) Panel 94P East Branch DuPage River (EBEB) Panels 36P-43P East Branch Sawmill Creek (SWSW) Panels 144P-145P East Branch Tributary No. 1 (EBE1) Panels 44P-45P East Branch Tributary No. 2 (EBE2) Panel 46P East Branch Tributary No. 3 (EBEB) Panels 47P-48P East Branch Tributary No. 4 (EBGL) Panels 49P-50P

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East Branch Tributary No. 5 (EBWI) Panels 51P-53P St. Procopius Creek (EBE6) Panels 54P-55P East Branch Tributary No. 7 (EBE7) Panels 56P-57P Ferry Creek (WBFE) Panels 151P-154P Ferry Creek Tributary No. 1 (WBFE) Panels 155P-157P Flagg Creek (DPFC) Panel 21P Ginger Creek (SCGC) Panels 95P-97P Heritage Oaks Tributary (SCGC) Panel 99P Klein Creek Tributary No. 1 (WBKC) Panels 167P-168P Klein Creek Tributary No. 2 (WBKC) Panel 169P Klein Creek Tributary No. 3 (WBKC) Panel 170P Klein Creek (WBKC) Panels 161P-166P Kress Creek (WBKR) Panels 171P-177P Lacey Creek (EBLA) Panels 58P-60P Lombard Tributary (SCGC) Panel 100P Mays Lake Tributary (SCGC) Panels 101P-102P Meacham Creek (SCSB) Panels 114P-115P Midwest Club Tributary (SCGC) Panel 103P North Branch St. Joseph Creek (EBSJ) Panel 80P Norton Creek (FRNC) Panel 87P Norton Creek Tributary (FRNC) Panel 88P North Unnamed Creek (DPWL) Panel 24P Plainfield Road Ditch (DPFC) Panels 17P-18P Prentiss Creek (EBPR) Panels 61P-64P Rott Creek (EBRC) Panels 65P-68P Salt Creek (SCSC) Panels 116P-130P Sawmill Creek (SWSW) Panels 136P-140P Sawmill Creek Tributary No. 1 (SWSW) Panels 148P-149P Sawmill Creek Tributary No. 3 (DPDP) Panels 10P-15P South Branch St. Joseph Creek (EBSJ) Panels 81P-82P South Fork Westwood Creek (SCWC) Panel 135P South Unnamed Creek (DPWL) Panel 23P Spring Brook Creek (SCSB) Panels 106P-112P Spring Brook No. 1 (WBSP) Panels 180P-184P Spring Brook No. 2 (DUSG) Panels 25P-29P Spring Road Tributary (SCOB) Panels 104P-105P St. Joseph Creek (EBSJ) Panels 69P-75P St. Joseph Creek Tributary (EBSJ) Panel 83P Sugar Creek (SCSU) Panels 131P-132P Sugar Creek Tributary A (SCSU) Panel 133P Tributary 1(A) (EBSJ) Panels 76P-78P Tributary 2(B) (EBSJ) Panel 79P Unnamed Creek (South of Foxcroft Road) (WBFX) Panels 158P-159P Unnamed Stream (North of 22nd Street) (EBTS) Panel 84P Unnamed Creek (South of 87th Street) (WBFX) Panel 160P

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Unnamed Tributary to Kress Creek (WBKR) Panels 178P-179P Wards Creek (SWWD) Panel 146P-147P Waubansee Creek (FRWA) Panels 89P-90P West Branch DuPage River (WBWB) Panels 185P-196P West Branch Sawmill Creek (SWSW) Panels 141P-143P West Branch Tributary No. 1 (WBW1) Panels 197P-198P West Branch Tributary No. 2 (Country Creek) (WBW2) Panels 199P-200P West Branch Tributary No. 3 (WBW3) Panels 201P-202P West Branch Tributary No. 4 (WBW4) Panels 203P-204P West Branch Tributary No. 5 (WBW5) Panel 205P West Branch Tributary No. 6 (WBW6) Panels 206P-208P West Branch Tributary No. 7 (WBW7) Panels 209P-211P West Branch Tributary to Spring Brook Creek (SCSB) Panel 113P Westwood Creek (SCWC) Panel 134P Winfield Creek (WBWF) Panels 212P-217P Winding Creek (WBWG) Panels 218P-219P 59th Street Ditch (DPFC) Panel 22P 63rd Street Ditch (DPFC) Panels 19P-20P 79th Street Ditch (DPFC) Panel 16P Exhibit 2 - Flood Insurance Rate Map Index Flood Insurance Rate Map

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1.0 INTRODUCTION

1.1 Purpose of Study

This countywide Flood Insurance Study (FIS) investigates the existence and severity of flood hazards in, or revises and updates previous FISs/Flood Insurance Rate Maps (FIRMs) for the geographic area of DuPage County, Illinois, including: the Villages of Addison, Bartlett, Bensenville, Bloomingdale, Carol Stream, Clarendon Hills, Downer’s Grove, Glen Ellyn, Glendale Heights, Hinsdale, Itasca, Lisle, Lombard, Oakbrook Terrace, Roselle, Villa Park, Warrenville, Wayne, Westmont, Wheaton, Willowbrook, Winfield, Wood Dale and Woodridge; the Cities of Aurora, Darien, Elmhurst, Naperville, Oak Brook, and West Chicago, and the unincorporated areas of DuPage County (hereinafter referred to collectively as DuPage County). The FIS and FIRMs for DuPage County will also show the portion of the Villages of Bolingbrook, Burr Ridge, Elk Grove, Hanover Park, Schaumburg, and Wayne; the Cities of Chicago and St. Charles that lie within DuPage County. The remaining portions of these communities lie within other counties; these communities have, therefore, been shown on DuPage County FIRMs for informational purposes only. The information contained on the DuPage County FIS for these communities is not to be used for flood insurance purposes.

This FIS aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This FIS has developed flood risk data for various areas of the county that will be used to establish actuarial flood insurance rates. This information will also be used by DuPage County to update existing floodplain regulations as part of the Regular Phase of the National Flood Insurance Program (NFIP), and will also be used by local and regional planners to further promote sound land use and floodplain development. Minimum floodplain management requirements for participation in the NFIP are set forth in the Code of Federal Regulations at 44 CFR, 60.3.

In some States or communities, floodplain management criteria or

regulations may exist that are more restrictive or comprehensive than the minimum Federal requirements. In such cases, it shall be understood that the state (or other jurisdictional agency) shall be able to explain these requirements and criteria.

1.2 Authority and Acknowledgments The sources of authority for this FIS are the National Flood Insurance Act

of 1968 and the Flood Disaster Protection Act of 1973. For each tributary in DuPage County, Table 1: “Tributary Study

Acknowledgements” lists the organizations and companies responsible for the development of the hydrologic and hydraulic analysis. For those organizations and companies contracted by FEMA to perform such

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analysis, a contract number and corresponding project order number were included. The listed finish date is the original date of study completion and does not reflect updates as a result of Letters of Map Revision (LOMR). Further Hydrologic and Hydraulic information for each tributary can be located in Section 3.0.

Table 1: Tributary Study Acknowledgements

Watershed Tributary Hydrologic and Hydraulic Analysis Performed By: FEMA Contract Numbers

Study Completion

Addison Creek

Donohue and Associates, Inc. study Addison Creek Stormwater Management System Evaluation, DuPage and Cook Counties, Illinois

Sep-88

Bensenville Ditch

Illlinois Department of Transportation study Strategic Planning Study for Flood Control - Bensenville Ditch

Dec-87

Black Partridge Creek

Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 Apr-79

Flagg Creek Harza Engineering Company Contract No. H-4562 and H-3978 Aug-78

Willow Creek Chicago District, U.S. Army Corps of Engineers


Des Plaines

Main Stem Chicago District, U.S. Army Corps of Engineers


Lily Cache Harza Engineering Company Contract No. H-3978 Feb-79 DuPage River

Spring Brook #2 Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement Nos. IAA-H-16-75, P.O. No. 21 and IAA-H-7-76, P.O. No. 1

Feb-78

Armitage Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-16-75, P.O. No 19, and Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 1

Nov-76

Army Trail Tributary



Crabtree Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-16-75 P.O. No. 21 and Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 1

Jan-77

Tributary #1 Chicago District, U.S. Army Corps of Engineers


Tributary #2 Camp Dresser and McKee: DEC Floodplain Mapping Report for East Branch DuPage River Tributary #2

Apr-02







Glen Crest Creek Chicago District, U.S. Army Corps of Engineers


East Branch DuPage River

Glen Park Chicago District, U.S. Army Corps of Engineers


2

Lacey Creek Chicago District, U.S. Army Corps of Engineers


Nov-81

Prentiss Creek Chicago District, U.S. Army Corps of Engineers


Jan-77

Rott Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement Numbers IAA-H-16-75, P.O. No.; and IAA-H-7-76, Amendment No. 3 to P.O. No.1

Sep-77

St. Joseph's Creek Chicago District, U.S. Army Corps of Engineers; and Harza Engineering Company

Inter-Agency Agreement No. IAA-H-16-75 P.O. No. 19 and Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 1; and Contract No. H-4562 respectively

Sep-77

Swift Meadows Chicago District, U.S. Army Corps of Engineers


22nd Street Chicago District, U.S. Army Corps of Engineers


Willoway Brook Chicago District, U.S. Army Corps of Engineers



Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 Sep-77

Brewster Creek Chicago District, U.S. Army Corps of Engineers


Indian Creek

U.S. Department of Agriculture and U.S. Soil and Conservation Service, Floodplain Management Study - Indian Creek and Tributaries, Kane and DuPage Counties, Illinois

Jun-86

Norton Creek Chicago District, U.S. Army Corps of Engineers


Fox River

Waubansee Creek Flood Insurance Studies for the City of Aurora and Kane and DuPage Counties

May-86

Wards Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 Apr-79 Sawmill

Creek

Main Stem Harza Engineering Company; Chicago District, U.S. Army Corps of Engineers

Contract No.H-3978; and Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 respectively

Apr-79

Bronswood Tributary

Illinois State Water Survey; Harza Engineering Company

Contract No. H-3942; and Contract No. H-4562 respectively Sep-78

Devon Avenue Tributary Soil Conservation Service Inter-Agency Agreement No. IAA-H-17-

75, P.O. No. 4 Nov-76

Ginger Creek DuPage County DEC: Floodplain Mapping Report for Ginger Creek - Salt Creek

Aug-94

Salt Creek

Oak Brook Tributary Illinois State Water Survey Contract No. H-4522 Sep-78

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Spring Brook Creek

Illinois State Water Survey; and Soil Conservation Service

Contract No. H-4522; and Inter-Agency Agreement No. IAA-H-17-75, P.O. No.4 respectively; with additional portions of Spring Brook studied by the U.S. Department of Agriculture, Weston Environmental Consultants, the Chicago District of the U.S Army Corps of Engineers, and the Illinois Division of Water Resources.

Sep-79

Sugar Creek Illinois State Water Survey Contract No. H-3942 Sep-78 Westwood Creek Harza Engineering Company Contract No. H-3809 Sep-76

Main Stem Soil Conservation Service; and the Illinois State Water Survey

Inter-Agency Agreement No. IAA-H-18-75, P.O. No. 4 and 6; and Contract No. H-3942 respectively

Sep-78

Cress Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement Nos. IAA-H-16-75, P.O. No. 21 and IAA-H-7-76, P.O. No 1

Feb-78

Ferry Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 1 and Inter-Agency Agreement No. IAA-H-16-75, P.O. No. 19

May-77

So. of Foxcroft Chicago District, U.S. Army Corps of Engineers


Feb-78

Klein Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 and Amendment No.2 to P.O. No. 19

Feb-78

Kress Creek Chicago District, U.S. Army Corps of Engineers


Spring Brook #1 Chicago District, U.S. Army Corps of Engineers


Steeple Run Tributary



Feb-78








Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 and Amendment No.2 to P.O. No. 19

Feb-78





Feb-78

West Branch DuPage River



Feb-78

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So. of 87th Chicago District, U.S. Army Corps of Engineers


Feb-78

Winfield Creek Chicago District, U.S. Army Corps of Engineers

Inter-Agency Agreement No. IAA-H-7-76, P.O. No. 19 Feb-78

Winding Creek Chicago District, U.S. Army Corps of Engineers


Feb-78


Inter-Agency Agreement Nos. IAA-H-16-75, P.O. No. 21 and IAA-H-7-76, P.O. No. 1 and 19

Feb-78

1.3 Coordination An initial Consultation Coordination Officer’s (CCO) meeting is held with

representatives of the communities, FEMA, and the study contractors to explain the nature and purpose of the FIS, and to identify the streams to be studied by detailed methods. A final CCO meeting is held typically with representatives of the communities, FEMA, and the study contractor to review the results of the FIS.

The dates of the initial and final CCO meetings held for DuPage County and the incorporated communities within its boundaries are shown in Table 2: “Initial and Final CCO Meetings”

Table 2: Initial and Final CCO Meetings

Community Initial CCO

Date Final CCO

Date Tributary Watershed

Acronym Village of Addison * 10-Nov-76

DPAC EBAT EBE1 EBEB EBSM SCSB SCSC SCWC

City of Aurora 18-Nov-93 24-Apr-96 DUSG FRIC FRWA WBFE WBWB

Village of Bartlett Jan-76 15-Sep-80 FRBC FRNC WBW2 WBWB Village of Bensenville 4-Oct-84 13-Oct-88 DPAC DPBD DPWL Village of Bloomingdale 19-Jul-77 28-May-80

EBAT EBEB EBSM SCSB WBKC WBW1 WBW4 WBWB

City of Bolingbrook * * DPLL EBEB Village of Burr Ridge Mar-76 4-May-79 DPDP DPFC SWSW Village of Carol Stream Jan-75 19-Jan-81

EBAR WBKC WBW4 WBWB WBWF

Village of Clarendon Hills Jul-77 16-Aug-79 DPFC SCBW

City of Darien * 29-Jan-79 DPBP DPDP DPFC DPLL EBPR EBSJ SWSW SWWD

Village of Downer’s Grove Jan-75 30-Jun-77

EBEB EBGP EBLA EBPR EBSJ EBTS SCBW SCGC SWSW

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SWWD

Elk Grove Village * * DPWL SCSC City of Elmhurst 4-Aug-80 8-Jan-80 DPAC SCSC SCSU Village of Glen Ellyn Dec-75 *

EBE2 EBEB EBGL EBWI WBSP WBWF

Village of Glendale Heights * *

EBAR EBAT EBE2 EBEB WBKC WBWF

Village of Hanover Park Jan-76 1-Jun-77

WBKC WBW1 WBW2 WBW4 WBWB

Village of Hinsdale Jul-77 3-Dec-79 DPFC SCBW SCSC Village of Itasca Jan-75 26-Oct-76 SCDA SCSB SCSC

Village of Lisle Dec-74 2-Jun-77 EBE6 EBEB EBPR EBRC EBSJ EBWI WBSR WBW6 WBW7

Village of Lombard Dec-75 12-Sep-77

EBE1 EBE3 EBEB EBGL EBGP EBLA EBTS SCGC SCSC SCSU SCWC

City of Naperville * *

DUSG EBE6 EBE7 EBEB EBRC FRWA WBCC WBFE WBFX WBSR WBW6 WBW7 WBW8 WBWB WBWG

Village of Oak Brook Aug-76 10-Jan-80 EBLA SCBW SCGC SCOB SCSCVillage of Oakbrook Terrace 30-Mar-77 30-Jan-80 SCGC SCOB SCSC SCSU Village of Roselle * * SCSB WBW1 WBWB Village of Schaumburg 13-Feb-75 17-Nov-77 SCSB WBWB City of St. Charles Dec-77 14-Oct-80 FRNC WBKR Village of Villa Park Aug-76 21-Jan-80 SCSC SCSU SCWC Village of Warrenville * *

EBRC WBCC WBFE WBSP WBWB

Village of Wayne * 16-Jan-81 FRBC FRNC WBWB City of West Chicago 21-Jan-76 15-Sep-77

FRNC WBKR WBW3 WBW4 WBW5 WBWB

Village of Westmont Jul-77 29-Oct-79 DPFC EBSJ SCBW SCGC Village of Wheaton * *

EBEB EBGL EBRC EBWI WBKC WBSP WBWF

Village of Willowbrook * 10-Jan-79 DPFC SWSW Village of Winfield 5-Jan-76 21-Jun-77 WBKC WBW5 WBWB WBWF Village of Wood Dale * *

DPAC DPBD DPWL SCSB SCSC SCWC

Village of Woodridge * 22-Jul-76

DPBP DPDP DPLL EBCR EBE6 EBE7 EBEB EBPR SWSW SWWD

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1.4 Regional Participation and Progress

After experiencing the damaging effects of flooding from the August 1987 flood event, DuPage County began to take measures to protect against future flooding. In 1989, the county began construction of over $100 million in flood control projects, the strict enforcement of a comprehensive stormwater and floodplain ordinance, and the development of updated regulatory floodplain maps throughout the county. These principal improvements were managed by a new entity, the Stormwater Management Division (SMD). This new organization is a division of the DuPage County Department of Environment Concerns (DEC). The SMD has managed the planning, design, and construction of many major flood control facilities over the last 12 years. The main purpose of the SMD implements the countywide stormwater ordinance. The SMD developed the countywide stormwater and floodplain ordinance in 1991, and started enforcement of the ordinance in February 1992. In 2000, DEC became the Department of Development and Environmental Concerns, and is still known as the DEC. In the effort to update aging flood plain maps, DuPage County DEC has devoted funds and efforts to develop more comprehensive hydrologic and hydraulic models for all currently mapped FEMA floodplain areas. These models, the majority of which utilizes 1-dimensional unsteady-state hydraulics, are in varied stages of development. When a tributary model has successfully passed DEC’s statistical scrutiny, the Flood Plain Mapping Report is submitted to FEMA for approval and a subsequent LOMR process. When this LOMR is approved, all information presented about the tributary in section 3.0 of this FIS will be removed and replaced with the new data. Per an agreement between FEMA and DuPage County, any further updates to these new models shall be the responsibility of DEC with oversight remaining at FEMA Region V. Therefore, when using this report for regulatory purposes it is important to understand that this FIS, a compilation of 57 tributaries, shall be in a changing state, but it will reflect at all times the best-available, FEMA-approved information.

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2.0 AREA STUDIED

2.1 Scope of Study This FIS covers the geographic area of DuPage County, Illinois. For a list of all watersheds and tributaries that have been explicitly modeled or studied for the purposes this FIS, please refer to Table 1 in Section 1.0 for quick reference, or Section 3.0 for more detailed watershed information. Limits of each detailed study are indicated on the Flood Profile (found in each tributary study breakdown within Section 3.0) and/or on the FIRM panel.

2.2 Community Description

DuPage County is situated in northeastern Illinois, approximately 25 miles directly west of the City of Chicago. DuPage County is bordered by Cook County on the north and east, Will County on the south, and Kane County on the west. The county encompasses 332.1 square miles and has a residential population of 904,161 according to the 2000 U.S. Census. The gross residential density at year 2000 was 2,722 people per square mile. Approximately 200 square miles or 60 percent of the county is in unincorporated areas. Temperature data is published for two climatological stations in DuPage County, Wheaton, and Argonne National Laboratories. The average annual temperature of Wheaton, which is typical for these stations, and for the county as well, is 49.8 degrees Fahrenheit (°F) with an annual monthly high in July of 76.5°F and monthly low in January of 9.2°F. The annual average precipitation at Wheaton is 39.26 inches. The highest monthly average precipitation occurs in August with a value of 7.65 inches (U.S. Department of Commerce, 1975). There are seven major drainage basins in DuPage County. These are: the Des Plaines River, the DuPage River, the East Branch DuPage River, the Fox River, Salt Creek, Sawmill Creek and the West Branch DuPage River.

2.3 Watershed Description

The following seven major watersheds within DuPage County are discussed in general detail in the following subsections. These subsections include a geographical description of the watershed, historical recorded flooding problems, and proposed and completed flood protection measures.

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2.3.1 DesPlaines River (DP)

2.3.1.1 Geographical Description The Des Plaines River includes all the easternmost tributaries located in DuPage County that are not within the Salt Creek Watershed. The general flow of the watershed is southeasterly in the headwaters and southwesterly at the Des Plaines River. Waters that enter such areas as Willow Creek, Bensenville Ditch or Addison Creek, found in the northeastern section of DuPage County, will flow east into Cook County, forming the Des Plaines River. As the Des Plaines River begins its turn to the southwest, it joins with Salt Creek, and then forms the southwest border between DuPage and Will Counties. The Des Plaines continues on a southwest course where it confluences with the Illinois River in Joliet. Additional DuPage County tributaries that join the Des Plaines are Flagg Creek, Black Partridge Creek, and various ditches. Sawmill Creek, and associated Wards Creek; the East Branch DuPage River; West Branch DuPage River; and the DuPage River are also tributary to the Des Plaines, but are considered in greater detail in subsequent sections. 2.3.1.2 Principal Flood Problems Addison Creek Within the Village of Bensenville, the three tributaries to Addison Creek do not experience severe flooding. The steep channel gradients help to convey high flows; therefore, overbank flooding is uncommon in most segments. Bensenville Ditch Bensenville Ditch is a small stream that flows from its headwaters in Bensenville for 3.7 miles to where it becomes Silver Creek. Flood events have occurred in March 1948, October 1954, August 1968, September 1972, March 1976, June 1978, March 1979, March 1982, May 1983 and October 1986. Overbank flooding is cause by the inability of the channel to convey and store large peak flows. Willow Creek The Willow Creek basin has recently become highly developed. Overbank flooding of this stream is caused by the inability of the channel to convey and store large peak flows. Flagg Creek

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The past history of flooding on Flagg Creek within the Village of Clarendon Hills indicates that flooding may occur during any season of the year. The majority of floods have occurred during March, April, and May; they are usually the result of spring rains and/or snowmelt. The 100-year discharge varies from 380 cfs at the downstream corporate limit to 190 cfs at the Eastern Avenue bridge. Damaging floods on Flagg Creek can be documented from discharge records for the USGS gage on Flagg Creek at Willow Springs (U.S. Department of the Interior, 1975). This gage (no. 05533000, drainage area 16.5 square miles) was established in 1949, and records are continuous to the present. The most severe floods in the Flagg Creek basin are listed below. Table 3: Flagg Creek Recorded Flood Discharges at Gage 05533000

Approximate Recurrence Water Discharge Interval Year (cfs) (years) 1961 2,680 85 1976 2,230 40 1975 1,630 15 1959 1,550 12 1957 1,350 8 1955 1,300 7

The portion of Flagg Creek flowing within the Village of Hinsdale flows through an underground culvert. For small flood events, the flow is contained in the culvert. For large floods, the culvert becomes surcharged and ponding occurs in the low-lying areas above the underground culvert. For a portion of 59th Street Ditch, the culvert is incapable of containing the 100-year storm, thus causing overland flow. Plainfield Road Ditch Flooding at Plainfield Road Ditch occurs on farmland just west of the Tri-State Tollway and, in a milder form, at the International Harvester Company. No buildings are flooded. In both cases, shallow channels contribute to the flooding. 59th Street Ditch Flooding occurs on the 59th Street Ditch when flow from upstream exceeds the capacity of the underground conduit system. Floodwaters flow through the subdivision known as Wood View Estates. On the east side of the subdivision, the water flows into a

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drainage ditch along the Tri-State Tollway. The water then flows south into 63rd Street Ditch, then east into Flagg Creek.

63rd Street Ditch The entire reach of 63rd Street Ditch east of State Route 83 in the Village of Willowbrook is subject to overbank flooding as described in the Hydrologic Atlases (U.S. Department of the Interior, HA-86, 1963; U.S. Department of the Interior, HA-149, 1963) and the report of the Des Plaines River Steering Committee (Des Plaines River Watershed Steering Committee, 1975). In addition, Wight and Company, in their Stormwater Management Study for Willowbrook, describes two areas draining to the 63rd Street Ditch which have been flooded (Wight and Company, 1977). One of these is at the corner of 59th Street and Clarendon Hills Road where flooding is due to inadequate drainage. This area flows into Marion Hills Ditch. The other is an area of overbank flooding along 63rd Street Ditch downstream from Lake Hinsdale to 63rd Street Ditch near Ridgemoor Drive and Quincy Drive.

79th Street Ditch Frequent residential damage occurs in one area in the Village of Burr Ridge. Flooding problems principally are caused by development in low lands that formerly served as natural drains. Overflow of the 79th Street Ditch causes damage to a residence on Hamilton Avenue south of 77th Street. The channel of this stream is not well defined in many places. This results in flooding of streets and yards in the area south of the intersection of 79th Street and Drew Avenue. 2.3.1.3 Flood Protection Measures Addison Creek A major storm occurred in March 1948 that caused substantial flooding on Addison Creek. Following the flood, the channel was deepened and widened. To alleviate serious flooding of the headwaters of Addison Creek, a 685-acre-ft stormwater retention reservoir (the George Street Reservoir) was constructed in Bensenville. The reservoir provides a reduction on the 100-yr flows for Addison Creek. All studied tributaries of Addison flow into the George Street Reservoir, where the water is stored to reduce the flooding on Addison Creek. Pumping the reservoir can control outflow from the tributaries.

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Flagg Creek There are no dams or reservoirs within the Flagg Creek. The main channel of Flagg Creek was improved in the past by paving a part of the channel between State Route 83 and Harris Avenue. Within the watershed, there are three facilities that provide some flood relief for local areas. These include the two interconnected detention ponds in Prospect Park, the Blue Lake detention area, and a grassed detention area in Hudson Park. These ponds do not have storage capacity for severe flooding events. The stream is not regulated by any floodplain management ordinance. 59th Street Ditch All of 59th Street Ditch within the Village of Hinsdale flows through an underground culvert. For small flood events, the flow is contained in a culvert. For large floods, the culvert becomes surcharged and ponding occurs in the low-lying areas above the underground culvert. The culvert is incapable of containing the 100-year storm, thus causing overland flow. There are no existing dams and reservoirs for the portion of the 59th Street Ditch flowing within the corporate limits of the Village of Hinsdale. 63rd Street Ditch The retention pond near the mouth of 63rd Street Ditch has been designed to retain 100-year flood flows for a short period of time without affecting the surrounding homes. For the portion of the stream flowing through the Village of Willowbrook, the community has previously completed several projects, including improving culverts and channels to reduce flood peaks. Lake Hinsdale, with a storage volume of about 35 acre-feet, controls discharges to 63rd Street Ditch from portions of the watershed west of Kingery Highway. Plainfield Road Ditch There is a small lake on the International Harvester Company property along Plainfield Road Ditch. Some flood runoff will spill into this lake, but the lake is too small to reduce the peak flood discharge. Bensenville Ditch, Willow Creek, and various ditches No information regarding flood protection measures for these tributaries is available.

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2.3.2 DuPage River (DU)

2.3.2.1 Geographical Description In DuPage County only small portions of watershed areas are attributed to the DuPage River: Spring Brook #2 and Lily Cache. Spring Brook #2 tributary drains to the south, while Lily Cache drains to the west into Will County, where they confluence with the DuPage River. Just upstream of the Spring Brook #2 confluence is the junction of the East and West Branches of the DuPage River. The DuPage River continues on a southerly course where it intersects Lily Cache and eventually the Des Plaines River in Joliet. 2.3.2.2 Principal Flood Problems Lily Cache – DuPage River Watershed No information regarding flooding problems for this tributary is available. Spring Brook #2 – DuPage River Watershed No information regarding flooding problems for this tributary is available. 2.3.2.3 Flood Protection Measures Lily Cache – DuPage River Watershed No information regarding flood protection measures for this tributary is available. Spring Brook #2 – DuPage River Watershed No information regarding flood protection measures for this tributary is available.

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2.3.3 East Branch DuPage River (EB)

2.3.3.1 Geographical Description The East Branch DuPage River flows southward in the central portion of DuPage County. Communities that are adjacent to this river are Bloomingdale, Glendale Heights, Lombard, Glen Ellyn, Downers Grove, Lisle and Woodridge. Other communities that contribute watershed area to the East Branch are Addison, Carol Stream, Darien, Oak Brook, Naperville, Wheaton and Westmont. The headwaters of the East Branch DuPage River begin in the Village of Bloomingdale and proceed to the south, not greatly altering course. Much of the river in the northern to central portions of the watershed is the result of channelization work from the early part of the 20th century. The major tributaries studied in this drainage basin are Prentiss Creek, St. Joseph Creek, Lacey Creek, Rott Creek, Willoway Tributary, Glen Crest Creek, Glen Park, Armitage Creek, 22nd Street, East Branch Tributary #2, Swift Meadows and Army Trail. 2.3.3.2 Principal Flood Problems Main Stem East Branch DuPage River Flooding along the East Branch DuPage River is minimal due to the construction of Westlake Lake in the Village of Bloomingdale, which is designed for a 100-year event. The total drainage area is 1,350 acres, most of which is residential. Lake Illini, the retention lake for the Indian Lakes subdivision, drains to the East Branch DuPage River. This development is built on a broad, shallow, perched valley. During intense rainfalls, standing water occurs in areas of equal elevation to Lake Illini. Because of a high water table of roughly 778 feet, only two feet of storage is available before the designed 100-year level of 780 feet is exceeded. Flood stages on the East Branch DuPage River are monitored by USGS gage no. 5540140. The three highest recorded floods for the stream are summarized in the following tabulation (U.S. Department of the Interior, 1978): Table 4: East Branch DuPage River Flood Stages at Army Trail Road (Gage No. 5540140) Water Return Surface Discharge Period DATE (Elev) (cfs) (years) 8/26/72 707.93 204 10 4/18/75 706.97 105 9/26/77 706.78 91

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The portion of the East Branch DuPage River flowing through the Village of Glen Ellyn presents the most severe flood hazard within Glen Ellyn. Recent floods along the East Branch DuPage River have occurred in April 1950, October 1954, September 1961, and August 1972. The August 1972 flood produced a discharge approximately equal to the computed 50-year discharge at Maple Avenue in the Village of Lisle. Recorded crests for this flood at two Illinois Division of Water Resources crest-stage gages near Glen Ellyn are as follows (U.S. Department of the Interior, 1973): Table 5: East Branch DuPage River August 1972 Recorded Flood Crests Location Elevation (feet NGVD) Butterfield Road 676.44 St. Charles Road 691.24 Damages in the Village of Glen Ellyn from overflow of the East Branch DuPage River and accompanying storm sewer back-up problems during the 1972 flood totaled approximately $500,000 for private homeowners and $40,000 for the Village of Glen Ellyn (Glen Ellyn News, 1972). Since discharge data are not available for the 1950, 1954, and 1961 floods, it is not possible to give an accurate estimate of their frequency. High water marks for these floods are indicated in (U.S. Department of the Interior, 1964; U.S. Department of the Interior, 1965).

22nd Street Tributary The principal cause of flooding in the area is the inadequate capacity of the natural channel to contain the runoff resulting from intense thunderstorm precipitation over the basin. Inundation of lands adjoining the river channel has been aggravated over the years by the gradual accumulation of silt. Buildup of sand bars and islands in the channel has resulted in the loss of channel capacity. Another factor lending itself to the poor flow characteristics of the channel in some reaches is the excessive growth of brush, light timber, and aquatic vegetation. In the past, the watershed has experienced almost none of the flood problems associated with the overflow of streams from their natural channels. As discussed above, the reason for this can be attributed to the undeveloped nature of the floodplain areas. However, the watershed has experienced flood damages as a result of the ponding of runoff compounded by the inability of the storm sewer system to convey the storm waters away in a timely manner.

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Armitage Creek Along the Armitage Ditch drainage system flooding conditions are aggravated by inadequate culverts. As more of the upstream reaches become developed, the downstream flood problems are intensified. Shallow flooding caused by ponding of runoff during heavy rains also occurs in several low-lying areas. The Village of Glendale Heights has experienced flooding on several occasions in the past, such as October 1954, July 1957, September 1961, June 1967 and August 1972. It is not possible to estimate the frequency of these events, as discharge data is not available for Armitage Creek. Monetary estimates of the resulting damages are also unavailable.

Crabtree Creek Flooding has occurred along Crabtree Creek, although most of the damages incurred during high stages of this stream result from basement flooding caused by sewer back-up. Signs of stream bank and bed erosion, caused by high water velocities, are evident along Crabtree Creek. East Branch DuPage River Tributary No. 2 Flooding problems have occurred at several locations in the Tributary No. 2 watershed, although these problems have generally been limited to yard flooding and road overtopping. Flooding has been reported by residents on Main Street, 2nd Street west of Forest Avenue, and along Park Avenue. Road overtopping has been reported on Main Street and Glenrise Avenue. Lacey Creek Low-lying areas of the watershed are subject to periodic flooding caused by overflow of the various watercourses within the community. The most severe flooding occurs in late summer as a result of heavy thunderstorms following periods of prolonged rainfall that have saturated the ground. Flooding during the winter months has usually been a result of heavy rainfall on frozen ground. Repeated damage to structures has occurred during past floods, especially those of October 1954, July 1957, and August 1972.

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Prentiss Creek Prentiss Creek presents the most severe flood hazard within the Village of Woodridge. Floods along Prentiss Creek, as well as along the village’s other streams, are usually highest in early spring, resulting from heavy rainfall and rapid snowmelt. Flooding along the creek is often aggravated by debris accumulation. Although just outside of the village limits, the constrictive culvert under State Route 53 causes substantial flooding of lands located just upstream of the bridge. Overbank flooding along Prentiss Creek is usually accompanied by back-up of street storm sewers and basement drains, two problems not specifically addressed by this study. Another major cause of flooding along 63rd Street is the inadequate capacity of the underground pipe that carries a small tributary stream from just upstream of 63rd Street at Winston Street to Prentiss Creek. A profile of the July 1963 flood, Prentiss Creek’s flood of record, is available. Recorded flood crest elevations for the USGS crest-stage gage at State Highway 53 are as follows: Table 6: Prentiss Creek Flood of Record (July 1963) Recorded Flood Crests at Illinois State Highway 53 (Downstream) Flood Flood Crest Elevation (NGVD) July 1963 663.94 August 1972 663.81 Accurate estimates of the recurrence intervals for these floods cannot be made since the above flood crest elevations were affected by backwaters from the East Branch DuPage River, and corresponding discharges are not available. St. Joseph’s Creek and the East Branch DuPage River The East Branch DuPage River and St. Joseph Creek have been sources of greatest concern in the Village of Lisle. Flooding has been reported on the East Branch DuPage River in 1948, 1950, 1954, 1957, and 1972. Flooding on St. Joseph Creek and the East Branch DuPage River in October 1954 caused the evacuation of many people. Water covered parts of Ogden Avenue, State Highway 53, Burlington Street, McKinley Avenue, Dumoulin Street, and River Drive. Flood waters reached the top of the Burlington Northern Railroad overpass on Main Street. A severe thunderstorm in July 1957 reportedly dropped 7.7 inches of rain in six hours in nearby Downers Grove, causing flooding along St. Joseph Creek in Lisle. The August 1972 flood, however, proved to be the flood of record on the East Branch DuPage River and the most damaging in the area. The 1972 flood is estimated to have a recurrence interval of about 50 years and resulted in a peak

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discharge on the East Branch DuPage River at village of Lisle of 2,500 cubic feet per second. Torrential rains were reported in excess of 7 inches in three hours in localized measurements. St. Joseph’s Creek The most severe flood of recent record occurred in August 1972, when flood waters rose near Belmont Avenue to an elevation of 691.13 feet on St. Joseph Creek (Downers Grove Reporter, 1954, et cetera). Based on the past history of floods within the area, this flood had a recurrence interval of 10 years. Rott Creek, Willoway Brook, Glen Crest Creek, Glen Park Tributary, Swift Meadows and Army Trail No flooding information particular to these tributaries is available. 2.3.3.3 Flood Protection Measures Main Stem – East Branch DuPage River Following the floods of 1954 and 1957 in the Village of Lisle, new emphasis was given to studies for the East Branch DuPage River. A Survey Report for Flood Control was completed in 1962 by the Department of Public Works and Buildings, Division of Waterways, covering this stream (State of Illinois, 1962). Subsequently, the East Branch DuPage River channel has been enlarged and levees built on both sides of the channel in the area from the Burlington Northern Railroad crossing to Middleton Avenue. From Maple Avenue to the Burlington Northern Railroad crossing, a levee was constructed on the east bank only. The levees along the East Branch DuPage River at Lisle will be overtopped by the 100-year flood. For the portion of East Branch DuPage River flowing through the Village of Glen Ellyn, in the past, damages associated with storm sewer back-up have been significant during periods of intense rainfall. In order to avoid these street and basement flooding problems, several detention and retention ponds have been constructed within the Village of Glen Ellyn. There are two low-flow dams located on the East Branch DuPage River. One is located in the Morton Arboretum near the Village of Lisle and the other is a controlling structure for the Churchill Woods Lagoon. There are no Federal flood control structures on the East Branch DuPage River or its tributaries within the unincorporated areas of DuPage County. Armitage Creek The Village of Glendale Heights initiated a comprehensive drainage study (Ralph F. Gross and Son, Associates, Inc, Village

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of Glendale Heights Comprehensive Storm Drainage Report, Nov. 1973) which highlighted flood problem areas and recommended corrective action including the installation of storm sewers, construction of retention ponds, channel dredging, the modification of existing drainage ordinances, and the adopting of new ordinances to preserve and control the natural flood plain. Many of the structural improvements recommended in this report have been constructed by the village. These measures have served to reduce and in some cases alleviate the flood problem in their vicinity. Such was the case on Armitage Fork, where channel paving and culvert enlargement significantly reduced the flood potential along this watercourse. East Branch Tributary No. 2 One of the flood protection measures that has been implemented in East Branch Tributary No. 2 is an overflow channel to handle high flow between Main Street and Park Boulevard. Low flows are carried in a corrugated metal storm sewer, and an overflow channel is provided for high flows. A crossover structure just east of Main Street is designed to assure full flow in the storm sewer before flow enters the overflow channel. There is also an overflow basin located between Forest and Park Street in the south side of Second Street, which detains flow when the capacity of the Second Street storm sewer is reached. Stream bank stabilization was completed by DuPage County on the overflow channel in 1994 for the reach between Main Street and Forest Avenue, and the reach between Park Boulevard and Goodrich Avenue. Between Forest Avenue and Park Boulevard, the overflow passes through a wide grassy area that may have been designed for flood storage. Glen Crest Creek Retention facilities were constructed in Glen Ellyn to reduce sewer back-up during intense rain events. These include the retention pond system at the Village Links golf course and the detention ponds at Panfish Park and Glen Ellyn Manor. During the August 1972 storm, no significant flooding was reported by areas serviced by the Village Links storm retention system. Prentiss Creek As the areas near Prentiss Creek have been residentially developed, substantial filling has occurred, and portions of the stream have been realigned. This is particularly true in that reach of the stream between State Route 53rd and 63rd Street. An independent citizens’ committee, the Prentiss Creek Flood Committee, has been formed to investigate solutions to flooding along Prentiss Creek. Additionally, the Village of Woodridge has recently begun discussions with neighboring communities to consider the regulation of storm runoff into Prentiss Creek.

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St. Joseph Creek Following the floods of 1954 and 1957, new emphasis was given to study St. Joseph Creek. A Survey Report for Flood Control was completed in 1962 by the Department of Public Works and Buildings, Division of Waterways, covering this stream (State of Illinois, 1962). St. Joseph Creek has been straightened and enlarged from its mouth to Curtiss Street in the portion flowing through the Village of Downers Grove. Channel and culvert improvements along St. Joseph Creek have significantly reduced the flood potential in some areas. During the flood of October 1954, extensive damage occurred in the downtown business area of the Village of Downers Grove. The village subsequently dredged a portion of St. Joseph Creek and that, together with clearing of debris from the channel, eliminated the flooding in the downtown area during the July 1957 flood. At the present time, a culvert from Mackie Avenue to Carpenter Street prevents the 100-year floodwaters from reaching the downtown business area. An earthen berm has been constructed just upstream of 55th Street to further reduce the flooding of downstream areas.

22nd Street Tributary There are no flood protection works on streams in the area. However, the area has an active storm water management program to alleviate some of the problems attributed to the ponding of runoff. Crabtree Creek, Lacey Creek, Rott Creek, Glen Park Tributary, Willoway Creek, Swift Meadows and Army Trail Tributaries No information regarding flood protection measures for these tributaries is available.

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2.3.4 Fox River (FR)

2.3.4.1 Geographical Description The Fox River flows from the State of Wisconsin through the Illinois Counties of Lake, McHenry, Kane, Kendall and LaSalle confluencing with the Illinois River at Ottawa, Illinois. DuPage County contributes watershed area to the Fox River from all tributaries bordering the west side of the County, with the exception of tributaries that drain to the West Branch DuPage River. The DuPage County tributaries that drain to the west, into Kane and Kendall Counties towards the Fox River, are: Brewster Creek, Norton Creek, Indian Creek and Waubansee Creek. 2.3.4.2 Principal Flood Problems Indian Creek Indian Creek and its tributary Selmarten Creek, are subject to severe flooding resulting from the inadequacy of the natural channel and appurtenant drainage structures to accommodate the high rates of runoff resulting from intense thunderstorms. Channels are inadequate to handle the sudden surge of runoff, and discharges are retarded by the poor flow characteristics of the channels and by inadequate capacities of bridges, culverts, and sewers that cross the streams. The major problem drainageway in Aurora is Indian Creek; it passes through a high-density development and urbanization is proceeding northward into the upper portions of the watershed. Waubansee Creek The Waubansee Creek watershed has the potential for urban development and care should be taken to ensure reasonable growth. No specific flooding problems on Waubansee Creek have been identified. Brewster and Norton Creeks The principal cause of flooding in the area is the inadequate capacity of the natural channel to contain the runoff resulting from intense thunderstorm precipitation over the basins. Inundation of lands adjoining the river channel has been aggravated over the years by the gradual accumulation of silt. Buildup of sand bars and islands in the channel has resulted in the loss of channel capacity. Another factor lending itself to the poor flow characteristics of some portions of channel is the excessive growth of brush, light timber and aquatic vegetation.

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The flood of record occurred in June 1967 when areas along Brewster and Norton Creeks were inundated. Damage resulting from this flood generally occurred in small, localized, rural areas. In the past, these tributaries experienced few problems associated with the overflow of streams from their natural channels. These watershed areas are comprised mostly of undeveloped or agricultural lands with very few structures in the flood plain. The flood hazards associated with the smaller streams are minor and again the flood plains are relatively undeveloped and are just now being developed. This, very little damage to structures has occurred in the past even during periods of extreme high water. 2.3.4.3 Flood Protections Measures Waubansee Creek There are two on-channel surface reservoirs on Waubansee Creek just upstream of the crossing of the Elgin Joliet and Eastern railroad. Construction of the reservoirs meet the requirements of the Federal Insurance Administration developed by a private development company for flood control related to urbanization. In addition to reservoirs, on-site retention storage is being installed throughout the watershed wherever substantial residential or commercial construction is taking place. Indian Creek, Norton Creek and Brewster Creek No information regarding flood protection measures for these tributaries is available.

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2.3.5 Salt Creek (SC)

2.3.5.1 Geographical Description Salt Creek is a tributary of the Des Plaines River, where a portion of the Creek flows through the eastern-central sections of DuPage County. Much of the watershed area in Salt Creek is densely developed, and has as a result suffered from significant flooding events (see 2.3.5.2 for more details). The communities of Roselle, Itasca, Wood Dale, Addison, Lombard, Villa Park, Elmhurst, Oak Brook, Oakbrook Terrace, Westmost, Clarendon Hills and Hinsdale all contribute watershed area to Salt Creek and its tributaries. Oak Brook Tributary flows southward from the northern section of Cook County to Oak Brook, then eastward to its confluence with the Des Plaines River, at Lyons. The DuPage County Salt Creek tributaries involved are: Spring Brook, Devon Avenue, Westwood Creek, Sugar Creek, Oakbrook Tributary, Ginger Creek and Bronswood Tributary. 2.3.5.2 Principal Flood Problems Main Stem Salt Creek Low-lying areas of Wood Dale, Itasca, Elmhurst, Addison, Oak Brook and Oakbrook Terrace are subject to periodic flooding caused by overflow of Salt Creek. As a result, storm drain outfalls become blocked and areas along small tributaries are flooded. The blocked storm runoff infiltrates the sanitary sewer system, creating sewer overloads and subsequent basement backup. Repeated damage to structures in the floodplain of Salt Creek has occurred during such floods as those in 1957, 1960, 1961, 1966, 1967, 1968, 1972, and 1973. The worst floods occurred in 1954, 1967, and 1972. The floods of 1954 and 1967 both have an estimated recurrence of 10 years as determined by SCS and the flood of 1972 has an estimated recurrence interval of 25 years as determined by the USGS. In Addison, a USGS crest-stage recorder is located on Salt Creek at the Lake Street Bridge. The flood-of-record occurred on August 27, 1972. An official or published discharge value for Salt Creek at Addison is not available. Stage-discharge relationships developed by Harza indicates that this flood had a peak discharge of about 3,340 cubic feet per second (cfs), a 50-year event. A 1973 report (U.S. Department of Agriculture, 1976) indicated that about 700 homes were within the flooded area of which about 500 applied for Federal aid after the flood had receded. Major damage was attributed to basement flooding by direct overland flow

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through windows or seepage through wall or foundation cracks. Additional damage occurred in some residences due to back-up through combined sewers. Dollar estimates of the damages are not available.

Spring Brook Creek and West Branch Tributary to Spring Brook Creek Spring Brook Creek drains the north sector of the Village of Bloomingdale. Flooding occurs because of inadequate channel capacities due to increased runoff from developing land within the Villages of Bloomingdale and Roselle. In the upper portion of the West Branch Tributary to Spring Brook Creek, flooding occurs because the land is flat, marshy, has considerable debris in the channel, and as such, has no well-defined course. After it crosses Lake Street, the West Branch Tributary to Spring Brook Creek flows northerly where the channel is well defined and flow is less obstructed. Flooding along the mainstem of Spring Brook Creek occurs downstream of the confluence with the West Branch Tributary to Spring Brook Creek. The creek is well defined but is usually clogged with debris. Flooding occurs because the gradient is much less than the upper reaches. Most flooding is confined along a narrow belt, paralleling the channel. Flood stages on Spring Brook Creek are monitored by USGS gages no. 5531080. The three highest recorded floods for the stream are summarized in the following tabulation (USGS, 1978): Table 7: Spring Brook (SC) Flood Stages – Gage No. 5531080

Water- Return Surface Discharge Period

DATE (Elev) (cfs) (years) 8/26/72 714.10 645 50 1/27/74 710.25 263 4/18/75 710.16 256 Devon Avenue Tributary Devon Avenue Tributary overflow causes periodic flooding in the low-lying areas of the Village of Itasca. As a result, storm drain outfalls become blocked and areas along small tributaries are flooded. The blocked storm runoff infiltrates the sanitary sewer systems, creating sewer overloads and subsequent basement back-up. Repeated damage to structures in the floodplains have occurred during such floods as those in 1957, 1960, 1961, 1966, 1967, 1968, 1972, and 1973. Westwood Creek Principal flood problems in the Village of Addison are street flooding caused by inadequate storm sewers and out-of-bank

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flooding along Salt and Westwood Creeks (U.S. Department of Agriculture, 1976). As stated previously, the flood-of-record occurred on August 27, 1972. It is unknown of the 700 impacted homes in the 1972 event, how many were affected by Westwood Creek alone. Oak Brook Tributary Overflow of Oak Brook Tributary and Salt Creek also causes principal flood problems in the City of Oakbrook Terrace. Oak Brook Tributary is ungaged. The best historical data available for flooding in Oakbrook Terrace are from a USGS recorder gage on Salt Creek, just north of Western Springs at Wolf Road about 7,000 feet downstream of the eastern corporate limit (U.S. Department of the Interior, 1976). At this point, Salt Creek has a drainage area of 114 square miles, and there is 31 years of data from the Western Springs gage (U.S. Water Resources Council, 1976). The 5 most significant floods of record are tabulated below: Table 8: USGS Recorder Gage of Salt Creek at Western Springs

Gage Total Discharge Height Height

Date (cfs) (ft) (ft) March 20, 1948 1,920 8.06 632.99 August 28, 1972 1,790 8.55 633.48 October 10, 1954 1,710 8.27 633.20 April 19, 1975 1,600 8.14 633.07 May 12, 1966 1,460 7.63 632.56 Sugar Creek, Ginger Creek, Westwood Creek, and Bronswood Creek No flooding information particular to these tributaries is available. 2.3.5.3 Flood Protection Measures Main Stem Salt Creek On Salt Creek, there is an existing low-flow dam at Oak Brook. There are a number of proposed reservoir projects in the Salt Creek watershed. • A multipurpose flood control facility along Salt Creek referred

to as the Elmhurst Quarry has been proposed for land directly north of the Chicago and Northwestern railroad, east of State Route 83 and west of Highland Avenue.

• One floodwater- retarding reservoir on Salt Creek (Busse

Woods Reservoir) is under construction approximately one mile upstream of the Village of Itasca. Construction was

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scheduled for completion in September 1976. This reservoir will reduce, but not eliminate, flooding in the Village of Itasca.

• The Kingery dike has been constructed on the east side of Salt

Creek in the northern Village of Villa Park and it contains the 500-year flood. This dike is the eastern boundary of the floodway and is in extreme northern Villa Park. In addition, there is a local zoning ordinance in the Village of Villa Park which restricts development within the floodplain.

An Act in Regulation to the Rivers, Lakes, and Streams of the State of Illinois, approved June 10, 1911, as amended (Illinois Revised Statutes, Chapter 19, 52 et seq, 1975) authorizes the Department of Transportation to define floodplains and establish a permit procedure for regulating construction within such defined floodplains (Illinois Department of Transportation, 1973). Spring Brook Creek and its Tributaries (Meacham Creek) Along Spring Brook in Roselle, the Centex Industrial Park provides 319.8 acre-feet of storage in a basin located just north of Irving Park Road. The Village of Roselle is planning another detention basin just south of the Chicago, Milwakee, St. Paul. and Pacific Railroad and north of Central Avenue. Sugar Creek, Ginger Creek, Westwood Creek, Devon Avenue, Oak Brook Tributary and Bronswood Creek No information regarding flood protection measures for these tributaries is available.

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2.3.6 Sawmill Creek (SW)

2.3.6.1 Geographical Description Sawmill Creek (a Des Plaines River Tributary) is the smallest watershed identified within DuPage County. Sawmill Creek, found in the southeastern section of DuPage County, draws watershed area from the communities of Darien, Willowbrook, Woodridge, Burr Ridge and Downers Grove. As Sawmill Creek approaches the Des Plaines River, the characteristics of the watershed change from mild or moderately-sloped residential to steeply-sloped forested. It is this lower watershed area that is home to the Waterfall Glen Forest Preserve and Argonne National Laboratory. Sawmill Creek’s one tributary, Wards Creek, joins Sawmill Creek on the south side of I-55, north of Argonne National Laboratory. Sawmill Creek confluences with the Des Plaines River approximately 7000 ft downstream of the Route 83 crossing of the Des Plaines River. 2.3.6.2 Principal Flood Problems

Inadequate storm sewers and out-of-bank flooding along Sawmill Creek and its tributaries, East Branch Sawmill Creek and West Branch Sawmill Creek cause principal flood problems in the City of Darien. Flooding from inadequate sewers occurs in the area bounded roughly by Plainfield Road and Willow Lane. Flood damages include residential damages, traffic disruptions, and associated neighborhood degradation caused by frequent flooding. There are no discharge gages located on Sawmill Creek, and peak discharges for past floods are not available. East Branch Sawmill Creek Flooding occurs along the entire reach of East Branch Sawmill Creek in the Village of Willowbrook. The June 13, 1976, flood caused damage along Eleanor Place and Virginia Court south of 75th Street and north of 79th Street. Floods on East Branch Sawmill Creek generally occur at the same time as those on Flagg Creek. The Flagg Creek basin borders the Sawmill Creek basin on the north and west. 2.3.6.3 Flood Protection Measures Sawmill Main Stem, Branches and Wards Creek Along the East Branch of Sawmill Creek, the Village of Willowbrook constructed Lake Hinsdale. With a storage volume of about 35 acre-feet, the facility controls discharges to both the

27

East Branch of Sawmill Creek and to the 63rd Street Ditch from portions of the watershed west of Kingery Highway. Other than this basin, there are no man-made flood protection measures on Sawmill Creek, the Branches of Sawmill Creek or Wards Creek. Sawmill Creek and the East Branch of Sawmill Creek are included in a floodwater management plan for the Des Plaines River watershed (“Des Plaines River Floodwater Management Plan and Environmental Assessment”, Des Plaines River Flood Plain Steering Committee, assisted by U.S. Department of Agriculture, January 1976). Measures recommended in that study have not been implemented.

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2.3.7 West Branch DuPage River (WB)

2.3.7.1 Geographical Description The West Branch DuPage River, the largest watershed in DuPage County, flows southward near the western edge of the county. The West Branch DuPage River flows through the communities of Hanover Park, Bartlett, Winfield, West Chicago, Warrenville, and Naperville. The communities of Roselle, Wayne, Bloomingdale, Carol Stream, Wheaton, Glendale Heights, St. Charles, Glen Ellyn, Lisle and Aurora also contribute watershed area to the West Branch DuPage River. The West Branch headwaters are found to the north of DuPage County in Cook County. The river enters DuPage County in the Village of Hanover Park where is winds its way west towards Bartlett. The river takes a slow serpentine approach, always to the south, changing bearing to the southeast through Warrenville and Naperville. Unlike the other more urbanized major river systems in DuPage County, the West Branch DuPage River has large forested buffers throughout its length. It is only when approaching the Warrenville and Naperville area where the river buffer decreases, also increasing the likelihood of flood impacts (please refer to section 2.3.7.2 for further information). The major tributaries studied in this drainage basin are Tributary #1 (Keeneyville), Klein Creek, Kress Creek, Springbrook #1, Ferry Creek, Cress Creek and Steeple Run. 2.3.7.2 Principal Flood Problems The West Branch DuPage River Main Stem Flooding along the West Branch DuPage River in the Village of Hanover Park is frequent and severe. Rapid urbanization in the drainage area since 1960 has led to increasing storm runoff, while at the same time, development in the floodplain in the north portion of the village has obstructed overbank flows during floods, raising water-surface elevations in the vicinity and generally worsening the damage conditions. A major storm in October 1954 caused record flooding in the Chicago area but Hanover Park was sparsely developed at that time. Other significant floods occurred on June 10, 1967, and on September 6, 1970, with an estimated 2.7 inches of rainfall in the drainage area. Peak discharges at the crest stage gage at Lake Street on the West Branch DuPage River reached 570 cfs in 1967 and 450 cfs in 1970. Damages in Hanover Park resulting from the 1970 flood were estimated at $470,000. In addition to flooding due to major storms, more frequent flooding occurs due to high waters in the river blocking storm sewer outlets and causing basement flooding (Harza Engineering Company, 1971).

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West Branch DuPage River also causes flooding within the City of Naperville. The amount of land subject to inundation within the City of Naperville from the West Branch DuPage River was significantly reduced by the construction of the Fawell Dam, just north of Naperville, by the Illinois Division of Water Resources in July 1972. The natural topography of the City of Naperville, particularly in the north-central portion of the city, has always been inadequate for the removal of storm water without some degree of total surface ponding occurring. This problem has been aggravated, however, by the continued development within Naperville, which has decreased the amount of uncovered ground available for saturation by precipitation. Major destructive floods along the West Branch DuPage River occurred in March 1948, April 1950, October 1954, July 1957, and August 1972. For the Illinois Division of Water Resources stream gage near Warrenville, the maximum recorded discharge occurred on August 26, 1972. Although records for this gage begin only in 1968, a high-water mark near the Warrenville gage indicates that the October 1954 flood conveyed even a greater discharge. Although the Warrenville stream gage crested on August 26 during the August 1972 flood, the majority of the damage within Naperville resulted from a storm occurring a few days later, on August 29, when an average of 5.9 inches of rain fell over the West Branch DuPage River Basin over a 5-hour period. Rain gages at two of Naperville’s sewage plants registered 4.75 and 5.25 inches of rainfall. As a result of the Fawell Dam’s recent construction, the West Branch DuPage River was reported to leave its banks only in the city’s southern portions. Property damage from the August 1972 flood was estimated in excess of $1.15 million for the Naperville area. During the period of October 9-11, 1954, the West Branch DuPage River Basin received an average of approximately 7.5 inches of rain, while Naperville received in excess of 9 inches. The gage at Shorewood, on the DuPage River, registered its highest recorded discharge for this storm. Klein Creek The principal causes of flooding in the area are the inadequate capacities of the natural channels to contain the runoff resulting from intense thunderstorm precipitation over the watershed. Additional flooding problems are created by the many channel and floodway constrictions resulting from inadequate waterway openings at bridges and the floodplain encroachments in urban areas. Many of the bridges, principally those along Klein Creek, have inadequate waterway openings which cause increased water

30

stages and flooding upstream of the bridge when discharges exceed their capacity. A matter of serious concern has been the growth of urban development on the floodplain of the river. Houses, garages, fences, and related construction have been built on the immediate banks of the river without adequate consideration of their effect on flood flows on the river and are subject to early inundation in high water stages and also serve to block effective flow of the floodwaters. Repeated damage to structures in the floodplains has occurred during such floods as those that occurred in 1942, 1947, 1948, 1949, 1950, 1951, 1953, 1954, 1957, 1959, 1961, 1962, 1966, 1967, 1972, and 1975. High water marks available along Klein Creek indicate elevations of approximately 743 feet in October 1954 and 743 feet in June 1962. Both of these storms have an estimated 10-year recurrence interval. Klein Creek drains the southwest section of the Village of Bloomingdale. Construction commenced in this area in 1979 and converted 77 percent of the area north of Army Trail Road from agricultural to commercial/residential use. Flooding occurs here because of a naturally high water table and poorly draining soils. The worst flooding occurred during the August 1972 storm when a water-surface elevation of 765.5 feet was reached at Army Trial Road. This elevation correlated well with a predicted 767.7 100-year elevation from a USACE study (USACE, 1975). The flood areas shown on the Flood Boundary and Floodway Map were provided by Mackie Consultants, the engineer for the developer (Mackie Consultants, Inc., 1977). Kress Creek Discussions with city representatives revealed that the major flood problems in West Chicago have been along Kress Creek. The greatest flood in the West Chicago area occurred in October 1954. Flood delineations for this event in West Chicago, taken from the Hydrologic Investigations Atlases (U.S. Department of the Interior, 1965, et cetera), indicate that areas adjacent to Kress Creek were flooded up to widths of 1,000 feet, while the Unnamed Tributary to Kress Creek was minimally affected. During the 1954 flood along the West Branch DuPage River, the portion of West Chicago upstream of State Highway 38 was flooded up to 250 feet from the channel on the right (west) bank, while downstream of the highway the left (east) bank was flooded for a distance of up to 350 feet from the channel. The peak discharge for the 1954 flood on the West Branch DuPage River in West Chicago had a recurrence probability of about 50 years. Specific damage

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estimates in West Chicago during the 1954 or 1972 floods were not found in the newspaper accounts of the flooding. Winfield Creek Principal flood problems in the City of Wheaton include overbank flooding from Winfield Creek, as well as local ponding of storm runoff at several locations. Major floods have occurred along Winfield Creek in May 1954, October 1954, and August 1972. Although the May 1954 flood caused only minor damage, substantial damages were sustained during the October flood of the same year. The following areas are among those hardest hit in the City of Wheaton during the October 1954 flood: areas surrounding Winfield Creek near North Side Park and Gary Avenue, the East Hawthorne subdivision, the area near Wheaton High School and the Wheaton Sanitary District plant on Weisbrook Road (Wheaton Experiences Much Loss, 1954). The August 1972 flood was the flood of record for Winfield Creek. Several cars were washed into Winfield Creek at Main Street from streets and parking lots. Damages during the 1972 flood in Wheaton were set at $5,055,000 (“Damage Estimate Set,” 1972). Gage readings for the August 26, 1972, flood along Winfield Creek are as follows (U.S. Department of the Interior, 1973): Table 9: Winfield Creek Gage Readings for 1972 Flood Event

Record Elevation Gage Location (NGVD) Winfield Creek Route 38 721.28

Gary Avenue 731.67 A discharge of 455 cfs was estimated at the Warrenville Road gage for Spring Brook Creek during the 1972 flood (U.S. Department of the Interior, 1973). This figure is slightly larger than the computed 100-year flood peak discharge of 430 cfs. No discharge data are available for Winfield Creek. Steeple Run As stated previously, the most severe flooding event in the City of Naperville was the August 1972 event. Some of the most severe flooding within Naperville took place in the Steeple Run Watershed, that sits primarily in the historical east side of the city. Both Huffman and Porter Streets suffered from severe flooding due to storm sewer overflow and local ponding.

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Cress Creek, Ferry Creek, Spring Brook #1 and Tributary #1 No significant flooding other than isolated drainage problems have been identified in these tributaries. 2.3.7.3 Flood Protection Measures Main Stem West Branch DuPage River After the damaging floods in 1948 and 1950, the Illinois Division of Water Resources made flood control studies on the West Branch DuPage River and other streams. After the floods of 1954 and 1957, these studies were expanded and a report on the DuPage River completed in 1962. This report recommended a program of channel improvement, some levee and floodwall construction, and a detention reservoir on the West Branch DuPage River upstream from the City of Naperville. These flood control measures were intended to control flood flows with an expected recurrence frequency of about 50 years. Subsequently, Fawell Dam was constructed approximately 0.25 miles upstream of U.S. Highway 34 (Ogden Avenue). This dam was designed with a flood control storage reservoir of 2,900 acre-feet, adequate for a 50-year flood. Three detention basins have been constructed by the City of Naperville since 1972, all of which have been designed to control runoff from the 100-year frequency rainfall. These basins are within the tributaries of Cress Creek and Steeple Run. In addition, another basin is proposed for the grounds of North Central College, and plans call for the expansion of an existing quarry, referred to as the Chicago Avenue Basin, to 100-year storm capacity. The West Branch DuPage River is the major cause of flooding in the Village of Hanover Park, Illinois, downstream from the Village of Schaumburg. Flood control works on the West Branch DuPage River in Hanover Park include extensive channel improvements and two retention basins. Retention Basin “A” will be located along the West Branch DuPage River near the Hanover Park-Schaumburg corporate boundary, about 1,500 feet west of Springingsguth Road. This basin will provide about 110 acre-feet of flood control storage, but will not affect flood elevations on the West Branch DuPage River in Schaumburg. Three dams have been built on the West Branch DuPage River. These are Warrenville Grove Dam, McDowell Forest Preserve Dam, and Fawell Dam. Warrenville Grove and McDowell Forest Preserve Dams are low-flow dams with no storage capacity. The other dam, Fawell Dam, lies north of Naperville and was constructed as a flood control dam. There are no new major flood

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control projects proposed for the West Branch DuPage River for the near future. Cress Creek Per a report performed by Lindley & Sons, Inc., Naperville-Northcentral Storm Drainage Report, a recommendation was made to build the Jefferson School Basin, at the intersection of Washington Street and Iroquois Avenue. This basin has since been completed. Steeple Run Per a report performed by Lindley & Sons, Inc., Naperville-Northcentral Storm Drainage Report, a recommendation was made to construct the County Commons Basin, just east of Huffman Street at School Street; and the Pembroke Greens Basin, just south of Cheshire Road between Charles Street and Richard Road. These basins have been completed. Creeks South of Foxcroft and South of 87th Street Earthen dikes with 1.0-foot diameter culverts are located along each of these tributaries to the West Branch DuPage River. These dikes were placed by private interests and cause an open field just southwest of the intersection of 87th Street and Washington Street to act as a detention pond. Because of their questionable construction, however, these dikes cannot be relied upon as flood control structures. Winfield Creek Development of floodplains within the City of Wheaton is currently regulated by Chapter 12.5 of the Wheaton City Code. The problem of overbank flooding along Winfield Creek was recently studied for the City of Wheaton by the engineering firm of Baxter and Woodman, Inc. As a result of these studies (Baxter and Woodman, Inc., 1975; Baxter and Woodman, Inc., 1976), several suggestions were made to alleviate the flooding situation along the stream. These include construction of berms around properties near Gary Avenue, reconstruction of several culverts, debris clearance, and construction of a retention pond.

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Klein Creek, Ferry Creek, Spring Brook #1, and Kress Creek No information regarding flood protection measures for these tributaries is available.

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3.0 ENGINEERING METHODS & FLOOD PLAIN MANAGEMENT APPLICATIONS

For the flooding source studied in detail in the county, standard hydrologic and

hydraulic study methods were used to determine the flood hazard data required for this FIS. Flood events of a magnitude that are expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period (recurrence interval) have been selected as having special significance for floodplain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and 500-year floods, have a 10-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long-term average period between floods of a specific magnitude, rare floods could occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood that equals or exceeds the 100-year flood (1-percent chance of annual exceedence) in any 50-year period is approximately 40 percent (4 in 10), and, for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding potentials based on conditions existing in the county at the time of completion of this FIS. Maps and flood elevations will be amended periodically to reflect future changes.

General Benchmark Information

All elevations are referenced to National Geodetic Vertical Datum of 1929 (NGVD) formerly referred to as mean sea level with the 1929 General Adjustment; elevation reference marks used in the study are shown on the maps. Qualifying bench marks within a given jurisdiction that are cataloged by the National Geodetic Survey (NGS) and entered into the National Spatial Reference System (NSRS) as First or Second Order Vertical and have a vertical stability classification of A, B, or C are shown and labeled on the FIRM with their 6-character NSRS Permanent Identifier.

Benchmarks cataloged by the NGS and entered into the NSRS vary widely in vertical stability classification. NSRS vertical stability classifications are as follows:

• Stability A: Monuments of the most reliable nature, expected to hold

position/elevation well (e.g., mounted in bedrock) • Stability B: Monuments which generally hold their position/elevation

well (e.g., concrete bridge abutment) • Stability C: Monuments which may be affected by surface ground

movements (e.g., concrete monument below frost line)

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• Stability D: Mark of questionable or unknown vertical stability (e.g., concrete monument above frost line, or steel witness post)

In addition to NSRS benchmarks, the FIRM may also show vertical control monuments established by a local jurisdiction; these monuments will be shown on the FIRM with the appropriate designations. Local monuments will only be placed on the FIRM if the community has requested that they be included, and if the monuments meet the aforementioned NSRS inclusion criteria. To obtain current elevation, description, and/or location information for benchmarks shown on the FIRM for this jurisdiction, please contact the Information Services Branch of the NGS at (301) 713-3242, or visit their Web site at www.ngs.noaa.gov. It is important to note that temporary vertical monuments are often established during the preparation of a flood hazard analysis for the purpose of establishing local vertical control. Although these monuments are not shown on the FIRM, they may be found in the Technical Support Data Notebook associated with this FIS and FIRM. Interested individuals may contact FEMA to access this data. Vertical Datum Issues

All FISs and FIRMs are referenced to a specific vertical datum. The vertical datum provides a starting point against which flood, ground, and structure elevations can be referenced and compared. Until recently, the standard vertical datum in use for newly created or revised FISs and FIRMs was the National Geodetic Vertical Datum of 1929 (NGVD 29). With the finalization of the North American Vertical Datum of 1988 (NAVD 88), many FIS reports and FIRMs are being prepared using NAVD 88 as the referenced vertical datum.

All flood elevations shown in this FIS report and on the FIRM are referenced to NGVD 29. Structure and ground elevations in the community must, therefore, be referenced to NGVD 29. It is important to note that adjacent communities may be referenced to NAVD 88. This may result in differences in base flood elevations across the corporate limits between the communities.

For more information on NAVD 88, see Converting the National Flood Insurance Program to the North American Vertical Datum of 1988, FEMA Publication FIA-20/June 1992, or contact the Vertical Network Branch, National Geodetic Survey, Coast and Geodetic Survey, National Oceanic and Atmospheric Administration, Rockville, Maryland 20910 (Internet address http://www.ngs.noaa.gov).

Floodplain Management Applications The NFIP encourages State and local governments to adopt sound floodplain

management programs. To assist in this endeavor, each FIS provides 100-year floodplain data, which may include a combination of the following: 10-, 50-, 100-,

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and 500-year flood elevations; delineations of the 100-year and 500-year floodplains; and 100-year floodway. This information is presented on the FIRM and in many components of the FIS, including Flood Profiles, Floodway Data tables, and Summary of Stillwater Elevation tables. Users should reference the data presented in the FIS as well as additional information that may be available at the local community map repository before making flood elevation and/or floodplain boundary determinations.

Floodplain Boundaries

To provide a national standard without regional discrimination, the 1-percent annual chance (100-year) flood has been adopted by FEMA as the base flood for floodplain management purposes. The 0.2-percent annual chance (500-year) flood is employed to indicate additional areas of flood risk in the community. For the stream studied in detail, the 100- and 500-year floodplains have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at a scale of 1:4,800, with contour intervals of 2 to 10 feet (State of Illinois, 1976; USGS, 1972, et cetera; State of Illinois, Floodplain Topographic Map for Salt Creek Watershed, 1975). Approximate Methods Flood boundaries for areas studied by approximate methods were delineated using USGS Flood Prone Area Maps, and Regulatory Flood Plain Maps (USGS, 1972, et cetera; USACE, 1975). The 100- and 500-year floodplain boundaries are shown on the FIRM. On this map, the 100-year floodplain boundary corresponds to the boundary of the areas of special flood hazards (Zones A, AH, and AE), and the 500-year floodplain boundary corresponds to the boundary of areas of moderate flood hazards. In cases where the 100- and 500-year floodplain boundaries are close together, only the 100-year floodplain boundary has been shown. Small areas within the floodplain boundaries may lie above the flood elevations but cannot be shown due to limitations of the map scale and/or lack of detailed topographic data. Floodways

Encroachment on floodplains, such as structures and fill, reduces flood-carrying

capacity, increases flood heights and velocities, and increases flood hazards in areas beyond the encroachment itself. One aspect of floodplain management involves balancing the economic gain from floodplain development against the resulting increase in flood hazard. For purposes of the NFIP, a floodway is used as a tool to assist local communities in this aspect of floodplain management. Under this concept, the area of the 100-year floodplain is divided into a floodway and a floodway fringe. The floodway is the channel of a stream, plus any adjacent floodplain areas, that must be kept free of encroachment so that the 100-year flood can be carried without substantial increases in flood heights. Minimum Federal

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standards limit such increases to 1.0 foot, provided that hazardous velocities are not produced. The floodway in this FIS is presented to local agencies as a minimum standard that can be adopted directly or that can be used as a basis for additional floodway studies.

In Illinois though, under Revised Statutes, Section 65f, Chapter 19 as amended in

1973 (Illinois Department of Transportation, 1973), encroachment in the floodplain is limited to that which will cause only an insignificant increase in flood heights. Thus, at the recommendation of the Illinois Division of Water Resources, a floodway having no more than a 0.1-foot surcharge has been delineated for this study.

Unless specifically stated in the individual tributary write-ups, the floodways were

computed on the basis of equal conveyance reduction from each side of the floodplain. The results of these computations are tabulated at selected cross sections for each stream segment for which a floodway is computed. The computed floodways are shown on the revised FIRM. In cases where the floodway and the 100-year floodplain boundaries are either close together or collinear, only the floodway boundary is shown.

The area between the floodway and 100-year floodplain boundaries is termed the

floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water-surface elevation of the 100-year flood by more than 1.0 foot at any point. Typical relationships between the floodway and the floodway fringe and their significance to floodplain development are shown in Figure 1, “Floodway Schematic.”

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FLOODWAY SCHEMATIC Figure 1

DuPage County Tributary Information

The following subsections discuss each tributary watershed in detail. Included in each subsection is a full tributary description, noting the major characteristics of the watershed. All hydrologic and hydraulic modeling used to generate discharge frequencies and subsequent recurrence interval elevations are included, followed by exhibits of the flood boundary, floodway data table and flood profile. Following approval by FEMA of updated models created through DuPage County, the tributary’s corresponding subfolder shall be updated as well. As such, the following subfolders shall be in a state of change until such time as all DuPage County tributaries have been updated. Even after this accomplishment, however, the subfolders are still subject to change based on LOMR requests. If there are particular questions related to this on-going process, please contact the DuPage County Department of Development and Environmental Concerns at 682-7230.

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3.1 Des Plaines River (DP)

3.1.1 Main Stem (DPDP)

3.1.1.1 Tributary Description In general, the Des Plaines River Main Stem begins its journey in the headwaters of urban / suburban Chicago, near to the Wisconsin / Illinois border. As the Main Stem winds its way to the southwest, joining Salt Creek in Lyons, Sawmill Creek near Lemont, and the DuPage River southwest of Joliet in Channahon, it eventually confluences with Illinois River at the Des Plaines Wildlife Conservation Area southwest of Joliet. Specifically, the Van Patten Woods Forest Preserve found east of I-94 and north of Wadsworth is the starting location of the Des Plaines River in the state of Illinois. From this location, the Des Plaines takes a direct route to the south passing through buffered areas, but increasing the surrounding impervious areas, such as: the Wadsworth Savannah Forest Preserve, Gurnee Woods Forest Preserve, Independence Grove Forest Preserve, Old School Forest Preserve, MacArthur Woods Forest Preserve, the Grainger Woods Conservation Area, Half-Day Forest Preserve, the Marriot-Lincolnshire Golf Course, Ryerson Conservation Area, Potawatomi Woods Forest Preserve, Dam #1 Woods Forest Preserve, Lake Avenue Woods Forest Preserve, Camp Pine Woods Forest Preserve, Chippewa Woods Forest Preserve, Dam #4 Forest Preserve, Catherine Chevalier Forest Preserve, and Schiller Woods Forest Preserve. Once leaving this last forest preserve, the Des Plaines passes through the city of Chicago rarely encountering any buffered areas. After joining Salt Creek at Lyons, the Des Plaines changes course to the southwest, paralleling the Stevenson Expressway and the Chicago Sanitary and Ship Canal. It is at this location where the Southeastern edge of DuPage County is formed. Though the County lines between Will and DuPage are not truly based on the Des Plaines River, it generally does follow the river for the greatest extent, until the river flows beyond the borders of DuPage County. The Main Stem of the Des Plaines continues to the southwest, then turns to the south. In the area of Crest Hill, on the north side of Joliet, the Des Plaines and the Chicago Sanitary and Ship Canal intersect. The Des Plaines continues through the urban area of Joliet, and intersects with the Illinois southwest of Channahon. 3.1.1.2 Hydrologic Analysis

Last printed 29 April 2004

Discharges for the 10-year, 50-year, and 100-year floods for the Des Plaines River Main Stem were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses of the Des Plaines River studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented in Table DPDP.1 below: Table DPDP.1: USGS Stream Gages Used for Hydrologic Analysis of the Des Plaines River

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Des Plaines River

at Lockport 05534050 700.0 7 A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is presented in Table DPDP.2 below: Table DPDP.2: Des Plaines River Drainage Area / Peak Discharge Relationship

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Des Plaines River At River Mile 26.75 684 6,060 7,800 9,000 10,000 3.1.1.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the source studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on

Section printed 29 April 2004

the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. The water-surface elevations for the Des Plaines River were computed using the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). “Manning’s ‘n’ Values,” shows the channel and overbank “n” values for the streams studied by detailed methods. See Table DPDP.3. for further information. Table DPDP.3: Des Plaines River Manning’s “n” Values

Manning’s “n” Values

Stream Channel "n" Overbank "n"

Des Plaines River 0.030 0.060 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.1.1.4 Flood Boundaries To reference the flood boundaries for the Des Plaines River Main Stem, see Map Panels: 0908, 0909, 1001, 1002, 1003, 1004, 1005 and 1006 3.1.1.5 Floodways Please reference attached Floodway Data Tables.

3.1.1.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE

CROSS SECTION DISTANCE

FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)

MEANVELOCITY(FEET PERSECOND)

BASE FLOOD WATER SURFACE ELEVATION(FEET NGVD)

WITHOUTFLOODWAY

WITHFLOODWAY INCREASEREGULATORY

Des Plaines River (DPDP)

DPDP0001 133,713 1,154 8,581 1.0 594.1 594.1 594.2 0.11

DPDP0002 136,340 1,020 7,531 1.2 594.2 594.2 594.3 0.11

DPDP0003 138,993 1,256 7,388 1.2 594.3 594.3 594.4 0.11

DPDP0004 141,634 705 4,718 1.8 594.5 594.5 594.6 0.11

DPDP0005 144,255 696 5,468 1.5 594.6 594.6 594.7 0.11

DPDP0006 146,913 388 3,268 2.6 594.8 594.8 594.9 0.11

DPDP0007 149,500 1,252 7,121 1.2 595.2 595.2 595.3 0.11

DPDP0008 151,718 1,012 6,524 1.3 595.3 595.3 595.4 0.11

DPDP0009 154,600 663 5,162 1.6 595.5 595.5 595.6 0.11

DPDP0010 156,031 674 5,530 1.5 595.6 595.6 595.7 0.11

FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATADUPAGE COUNTY

AND INCORPORATED AREAS DES PLAINES RIVER (DPDP)

In feet above mouth1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Sawmill Creek Tributary No. 3 (DPDP)

DPDP0011 978 111 368 1.5 595.2 595.2 595.4 0.21

DPDP0012 2,208 31 100 5.6 603.1 603.1 603.1 0.01

DPDP0013 2,633 57 260 2.1 618.1 618.1 618.1 0.01

DPDP0014 4,775 111 337 1.7 637.4 637.4 637.5 0.11

DPDP0015 6,269 20 144 3.0 652.0 652.0 652.0 0.01

DPDP0016 6,436 180 775 0.7 652.4 652.4 652.4 0.01

DPDP0017 7,299 21 137 4.1 657.5 657.5 657.6 0.11

DPDP0018 8,464 53 136 3.1 670.3 670.3 670.4 0.11

DPDP0019 9,023 48 80 5.2 671.4 671.4 671.5 0.11

DPDP0020 10,911 67 116 3.6 688.4 688.4 688.5 0.11

DPDP0021 11,677 66 78 4.4 700.4 700.4 700.4 0.01

DPDP0022 12,411 228 459 0.9 703.5 703.5 703.5 0.01

DPDP0023 13,371 11 42 1.4 706.0 706.0 706.1 0.11

DPDP0024 13,630 32 56 1.1 706.4 706.4 706.5 0.11


AND INCORPORATED AREAS SAWMILL CREEK TRIBUTARY NO. 3 (DPDP)

In feet above confluence with Des Plaines River1

TAB

LE 5

565

570

575 575

580 580

585 585

590 590

595 595

600 600

132000 133000 134000 135000 136000 137000 138000 139000 140000 141000 142000 143000 144000 145000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE MOUTH

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

DES

PLAI

NES

RIVE

R (D

PDP)

08P

DPDP

0001

DPDP

0002

DPDP

0003

DPDP

0004

DPDP

0005

COUN

TY B

OUND

ARY

CONF

LUEN

CE O

F SA

WM

ILL

CREE

K

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3

LEGEND500-YEAR FLOOD

100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED

CROSS SECTION LOCATION

CONF

LUEN

CE O

F

565

570

575 575

580 580

585 585

590 590

595 595

600 600

145000 146000 147000 148000 149000 150000 151000 152000 153000 154000 155000 156000 157000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

DES

PLAI

NES

RIVE

R (D

PDP)

09P

DPDP

0006

DPDP

0007

DPDP

0008

DPDP

0009

DPDP

0010

COUN

TY B

OUND

ARY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


580

585

590 590

595 595

600 600

605 605

610 610

615 615

620 620

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH DES PLAINES RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

10P

DPDP

0011

DPDP

0012

CONF

LUEN

CE W

ITH

DES

PLAI

NES

RIVE

R

RAIL

ROAD

FORE

ST P

RESE

RVE

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM DES PLAINES RIVER

605

610

615 615

620 620

625 625

630 630

635 635

640 640

645 645

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

11P

DPDP

0013

DPDP

0014


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


630

635

640 640

645 645

650 650

655 655

660 660

665 665

5200 5400 5600 5800 6000 6200 6400 6600 6800 7000 7200 7400 7600 7800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

12P

DPDP

0015

DPDP

0016

DPDP

0017

BLUF

F RO

AD

EAST

WOO

D DR

IVE

FRON

T ST

REET

CASS

AVE

NUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


650

655

660 660

665 665

670 670

675 675

680 680

685 685

7800 8000 8200 8400 8600 8800 9000 9200 9400 9600 9800 10000 10200 10400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

13P

DPDP

0018

DPDP

0019

PARK

ING

LOT

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


675

680

685 685

690 690

695 695

700 700

705 705

710 710

10400 10600 10800 11000 11200 11400 11600 11800 12000 12200 12400 12600 12800 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

14P

DPDP

0020

DPDP

0021

DPDP

0022

CLAR

ENDO

N HI

LLS

ROAD

QUAR

TER

LANE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


690

695

700 700

705 705

710 710

13000 13200 13400 13600 13800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 3 (D

PDP)

15P

DPDP

0023

DPDP

0024

91ST

STR

EET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.1.2 Addison Creek (DPAC)

3.1.2.1 Tributary Description Within the confines of DuPage County, Addison Creek has a total watershed area of 5815 acres. Situated on the northeastern edge of DuPage County, Addison Creek and its reaches flow from west to east, confluencing with the Des Plaines River in Cook County. Much of the watershed is found within the confines of the Village of Bensenville and Elmhurst, an area with older residential and commercial structures, and a good portion of the upper watershed is storm sewered. The Main Stem of Addison Creek and its primary reach both start west of Illinois Route 83 (Kingery Highway) within residential subdivisions. The reaches travel to the east passing underneath Route 83 and eventually opening up within the White Pines Golf Course. Both reaches continue to the east passing under York Road, where they are joined at the George Street Reservoir. George Street Reservoir releases the flow to the south where it enters the River Forest Country Club, Mt. Emblem Cemetery and then a detention area. Flow then resumes to the east where it passes under I-294 and exits DuPage County.

3.1.2.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Addison Creek. Peak discharges for Addison Creek and Addison Creek’s South Tributary, which does not have a streamflow gage, were determined using the HEC-1 computer program (USCOE, HEC-1 Hydrograph Package 723-X6-L2010) and the SCS hydrograph feature of the HEC-1 model (SCS, National Engineering Handbook, Section 4 “Hydrology”). Peak Discharges for the Addison Creek Tributaries were computed using the TR-20 computer program (SCS, Technical Release No. 20 – Computer Program for Project Formulation, Hydrology). The 500-year peak discharge was determined using a linear extrapolation preformed on probability paper. Peak discharge-drainage area relationships for the 10-, 50-, 100-, and 500-year floods of each flooding source studied in detail are presented in Table DPAC.1. Table DPAC.1: Addison Creek Summary of Discharges

Summary of Discharges


Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Addison Creek Tributary #1 – at George Street Reservoir 0.93 54 96 122 185 Addison Creek Tributary #2 - at York Road 1.18 56 88 106 146 - at Church Road 0.33 28 44 50 68 Addison Creek Tributary #3 - about 300 ft d/s George Street 1.20 50 62 86 115 - at Church Road 0.23 18 28 34 43 Addison Creek South Tributary - at York Road 1.68 426 736 915 1,421 - at Fairway Drive 1.12 202 346 429 693 Elevations for floods of the selected recurrence intervals of George Street Reservoir are presented in Table DPAC.2. Table DPAC.2: Addison Creek Summary of Elevations (George Street Reservoir)

Summary of Elevations Flooding Source Peak Elevation (Ft – NGVD) And Location 10-yr 50-yr 100-yr 500-yr George Street Reservoir 643.0 649.0 652.0 657.0 3.1.2.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.


Roughness coefficients (Manning’s “n”) were assigned based on doled inspection, photographs, and engineering judgment (USGS, Roughness Characteristics of Natural Channels; Chow, Open Channel Hydraulics). Roughness values range from 0.030 to 0.075 for the channels and from 0.030 to 0.095 for the overbanks. Water-surface elevations for floods of the selected recurrence intervals on Addison Creek’s South Tributary were computed using the HEC-2 step-backwater computer program (USCOE, HEC-2Water Surface Profiles 723-X6-L202A). Starting water-surface elevations for Bensenville Ditch were taken from the Flood Insurance Study for the City of Chicago, Illinois (FEMA, Flood Insurance Study – City of Chicago, Cook and DuPage Counties, Nov 1983). Starting water-surface elevations on the Addison Creek tributaries were determined using the slope-area method. Water-surface profiles for present conditions on the Addison Creek tributaries were determined for the 10-, 50-, 100-, and 500-year floods using the WSP-2 computer program (USDA – SCS, Technical Release No. 61, WSP-2 Computer Program). Water Surface Profiles for present conditions on Addison Creek were determined for the 10-, 50-, and 100-year floods using the HEC-2 step-backwater computer program (USCOE, HEC-2Water Surface Profiles 723-X6-L202A). Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. In cases where the 50- and 100-year flood elevations are close together, due to limitations of the profile scale, only the 100-year profile has been shown. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.1.2.4 Flood Boundaries To reference the flood boundaries for Addison Creek, see Map Panels: 0305, 0306, 0308, 0309, 0603 and 0606 3.1.2.5 Floodways


Please reference attached Floodway Data Tables. 3.1.2.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Addison Creek (DPAC)DPAC0001 61,193 280 1,416 0.7 657.8 657.8 657.8 0.01

DPAC0002 61,834 305 1,367 0.7 657.8 657.8 657.8 0.01

DPAC0003 62,384 500 2,701 0.0 657.8 657.8 657.8 0.01

DPAC0004 62,774 523 2,453 0.0 657.8 657.8 657.8 0.01

DPAC0005 63,816 72 432 0.2 657.9 657.9 657.9 0.01

DPAC0006 64,481 71 397 0.2 657.9 657.9 657.9 0.01

DPAC0007 65,006 175 1,068 0.1 657.9 657.9 657.9 0.01

DPAC0008 65,991 254 857 0.1 657.9 657.9 657.9 0.01

DPAC0009 66,171 355 1,325 0.1 657.9 657.9 657.9 0.01


AND INCORPORATED AREAS ADDISON CREEK (DPAC)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Addison Creek Tributary No. 1 (DPAC)

DPAC0010 71,096 121 271 0.4 656.5 656.5 656.6 0.11 2


AND INCORPORATED AREAS ADDISON CREEK TRIBUTARY NO. 1 (DPAC)

In feet above confluence with Des Plaines River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



DPAC0011 69,441 21 38 2.9 662.6 662.6 662.7 0.11

DPAC0012 70,242 65 115 0.0 662.8 662.8 662.9 0.11

DPAC0013 73,465 54 47 1.5 672.3 672.3 672.4 0.11




TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



DPAC0014 70,149 60 182 0.5 662.6 662.5 662.6 0.11 2

DPAC0015 70,640 50 193 0.4 663.1 663.1 663.2 0.11

DPAC0016 73,887 16 18 3.5 676.1 676.1 676.2 0.11

DPAC0017 75,994 249 1,265 0.0 682.5 682.5 682.5 0.01



In feet above confluence with Des Plaines River2 Elevation computed without consideration of backwater effects from Addison Creek Tributary No. 2

1

TAB

LE 5

630

635

640 640

645 645

650 650

655 655

660 660

665 665

61000 61500 62000 62500 63000 63500 64000 64500 65000 65500 66000 66500 67000 67500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ADDI

SON

CREE

K (D

PAC)

01P

DPAC

0001

DPAC

0002

DPAC

0003

DPAC

0004

DPAC

0005

DPAC

0006

DPAC

0007

DPAC

0008

DPAC

0009

LIM

IT O

F FL

OODI

NG A

FFEC

TING

COU

NTY

COUN

TY L

INE

ROAD

COUN

TY B

OUND

ARY

BRID

GE 2

CEM

ETAR

Y RO

AD

CEM

ETER

Y RO

AD

GRAN

D AV

ENUE

UNNA

MED

ROA

D

GEOR

GE S

TREE

T

GEOR

GE S

TREE

T RE

SERV

OIR

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

THE 50-YEAR FLOOD PROFILE UPSTREAM OF STATION 66, 831 IS NOT AVAILABLE

640

645

650 650

655 655

660 660

665 665

69000 69500 70000 70500 71000 71500 72000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ADDI

SON

CREE

K TR

IBUT

ARY

NO. 1

(DPA

C)

02P

DPAC

0010

CONF

LUEN

CE W

ITH

GEOR

GE S

TREE

T RE

SERV

OIR

JEFF

ERSO

N AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

690

68500 69500 70500 71500 72500 73500 74500 75500 76500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ADDI

SON

CREE

K TR

IBUT

ARY

NO. 2

(DPA

C)

03P

DPAC

0011

DPAC

0012

DPAC

0013

CONF

LUEN

CE A

T GE

ORGE

STR

EET

RESE

RVOI

RSP

ILLW

AY

CONF

LUEN

CE O

F AD

DISO

N CR

EEK

TRIB

UTAR

Y NO

. 3

YORK

ROA

D

CHUR

CH R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


650

655

660 660

665 665

670 670

675 675

680 680

685 685

69000 69500 70000 70500 71000 71500 72000 72500 73000 73500 74000 74500 75000 75500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ADDI

SON

CREE

K TR

IBUT

ARY

NO. 3

(DPA

C)

04P

DPAC

0014

DPAC

0015

DPAC

0016

CONF

LUEN

CE W

ITH

ADDI

SON

CREE

K TR

IBUT

ARY

NO. 2

APAR

TMEN

T DR

IVEW

AY

APAR

TMEN

T DR

IVEW

AY

GEOR

GE S

TREE

T

DENN

IS D

RIVE

DENN

IS D

RIVE

S. Y

ORK

ROAD

FORE

ST V

IEW

ROA

D

CONF

LUEN

CE O

F TR

IBUT

ARY

A


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE FROM 2,047 FEET UPSTREAM OFFOREST VIEW ROAD TO 4,099 FEET UPSTREAM OF FOREST

CULVERTS

FROM ADDISON CREEK NO 2100-YEAR BACKWATER

660

665

670 670

675 675

680 680

685 685

690 690

75500 76000 76500 77000 77500 78000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ADDI

SON

CREE

K TR

IBUT

ARY

NO. 3

(DPA

C)

05P

DPAC

0017

ARTH

UR C

OURT

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


VIEW ROAD

CULVERT

FOREST VIEW ROAD TO 4,099 FEET UPSTREAM OF FOREST*DATA NOT AVAILABLE FROM 2,047 FEET UPSTREAM OF

3.1.3 Bensenville Ditch (DPBD)

3.1.3.1 Tributary Description Bensenville Ditch is a small, thin watershed tributary to the Des Plaines River. The total watershed area within DuPage County totals 1640 acres. The stream’s headwaters are found within unincorporated DuPage County, west of Wooddale Road just south of Irving Park Blvd in an older residential subdivision. Bensenville Ditch then proceeds to the east into the Village of Bensenville, hugging the south side of Irving Park Road. The stream passes underneath Irving Park Road and York Road, entering the Chicago – O’Hare Airport grounds, thus departing DuPage County. Much of the tributary area to Bensenville Ditch is high-density residential and light commercial. Given the long, thin shape of the watershed, and the high imperviousness of the terrain, it would be expected to see some quick, high-peak, runoff events.

3.1.3.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Bensenville Ditch. A generalized rainfall-runoff model was developed for Bensenville Ditch by the Illinois Department of Transportation using the HEC-1 computer program (USCOE, HEC-1 Hydrograph Package 723-X6-L2010). The model was based on SCS curve numbers (CN) and hydrograph lag times (TLAGs) for input. The relative imperviousness of each subarea was derived using the land cover, soil group, and average CN for each area. The resulting CN values for each subarea were used in the model for runoff loss and soil abstraction. The TLAG was derived using the modified curve number method outlined in SCS Technical Release No. 55 (SCS, Urban Hydrology for Small Watersheds). The model was run to determine flows for recurrence intervals of 2 to 100 years with rainfall for 6, 12, and 24 hours. The rainfall values were obtained from a report titled “Effects of Basin Rainfall Estimates on Dam Safety Design in Illinois” (ISWS). The results of the HEC-1 model run on Bensenville Ditch indicate that the 12-hour storm with a Huff 3 distribution (ISWS) will produce the maximum storm runoff from the watershed. Peak discharge-drainage area relationships for the 10-, 50-, 100-, and 500-year floods of each flooding source studied in detail are presented in Table DPBD.1.


Table DPBD.1: Bensenville Ditch Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Bensenville Ditch - just d/s of Garden Ave 1.82 367 663 774 N/A - just d/s of York Road 1.56 296 527 610 N/A - just d/s of Mason Street 1.32 283 510 564 N/A - at Church Street 1.07 246 470 520 N/A 3.1.3.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Roughness coefficients (Manning’s “n”) were assigned based on doled inspection, photographs, and engineering judgment (USGS, Roughness Characteristics of Natural Channels; Chow, Open Channel Hydraulics). Roughness values range from 0.030 to 0.075 for the channels and from 0.030 to 0.095 for the overbanks. Water-surface elevations for floods of the selected recurrence intervals on Bensenville Ditch were computed using the HEC-2 step-backwater computer program (USCOE, HEC-2Water Surface Profiles 723-X6-L202A). Starting water-surface elevations for Bensenville Ditch were taken from the Flood Insurance Study for the City of Chicago, Illinois (FEMA, Flood Insurance Study – City of Chicago, Cook and DuPage Counties, Nov 1983). Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. In cases where the 50- and 100-year flood elevations are close together, due to limitations of the profile scale, only the 100-year profile has been shown. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain


unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.1.3.4 Flood Boundaries To reference the flood boundaries for Bensenville Ditch, see Map Panels: 0302, 0303, 0305 and 0306 3.1.3.5 Floodways Please reference attached Floodway Data Tables. 3.1.3.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Bensenville Ditch (DPBD)

DPBD0001 44,858 228 757 0.5 661.8 661.8 661.8 0.01

DPBD0002 45,491 673 1,718 0.5 661.9 661.9 661.9 0.01

DPBD0003 46,268 14 74 8.2 661.9 661.9 662.2 0.31

DPBD0004 46,448 15 198 3.1 667.6 667.6 667.8 0.21

DPBD0005 46,669 786 2,852 0.2 667.8 667.8 668.0 0.21 2

DPBD0006 47,718 485 1,836 0.3 667.8 667.8 668.0 0.21

DPBD0007 48,048 504 2,360 0.2 667.9 667.9 668.1 0.21

DPBD0008 48,735 481 2,298 0.2 667.9 667.9 668.1 0.21 2

DPBD0009 49,609 284 442 1.3 667.9 667.9 668.1 0.21 2

DPBD0010 50,138 63 185 2.8 668.1 668.1 668.3 0.21


AND INCORPORATED AREAS BENSENVILLE DITCH (DPBD)


1

TAB

LE 5

640

645

650 650

655 655

660 660

665 665

670 670

43500 44000 44500 45000 45500 46000 46500 47000 47500 48000 48500 49000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BENS

ENVI

LLE

DITC

H (D

PBD)

06P

DPBD

0001

DPBD

0002

DPBD

0003

DPBD

0004

DPBD

0005

DPBD

0006

DPBD

0007

DPBD

0008

ORCH

ARD

AVEN

UE

GARD

EN A

VENU

E

RAIL

ROAD

RAIL

ROAD

N. Y

ORK

ROAD

AUTO

PAR

TS R

OAD

IRVI

NG P

ARK

BOUL

EVAR

D

MAS

ON S

TREE

T

LEGEND500-YEAR FLOOD*100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

*DATA NOT AVAILABLE

640

645

650 650

655 655

660 660

665 665

670 670

49000 49500 50000 50500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BENS

ENVI

LLE

DITC

H (D

PBD)

07P

DPBD

0009

DPBD

0010

CHUR

CH R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY

LEGEND500-YEAR FLOOD*100-YEAR FLOOD50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

3.1.4 Black Partridge Creek (DPBP)

3.1.4.1 Tributary Description Black Partridge Creek is tributary to the Des Plaines River, and is adjacent to Argonne National Laboratories to the west. This watershed has a total area of 1750 acres, with low density residential and high open space / forest components. Black Partridge Creek begins within a residential section of the Village of Woodridge, east of Orchard Road, west of Lemont Road and north of I-55. The stream passes underneath Charing Cross Road twice and serpentines under Westminster Drive. Black Partridge takes a southern bearing and flows through a culvert at I-55. Upon exiting the I-55 culvert, Black Partridge continues to the south, collecting feeder ditches from both Unincorporated DuPage County and the Village of Woodridge. The Main Stem of Black Partridge Creek follows the east-side ditch of Orchard Road, passing underneath Orchard road near Internationale Drive. The creek enters a Forest Preserve Zone, exits DuPage County, and makes its way to the Des Plaines River. 3.1.4.2 Hydrologic Analysis

There is no information regarding the regulatory hydrologics of Black Partridge Creek within the confines of DuPage County. 3.1.4.3 Hydraulic Analysis There is no information regarding the regulatory hydraulics of Black Partridge Creek within the confines of DuPage County. 3.1.4.4 Flood Boundaries To reference the flood boundaries for Black Partridge Creek, see Map Panels: 1001 and 1004. 3.1.4.5 Floodways No floodway information is currently available for this tributary. 3.1.4.6 Flood Profiles No flood profile information is currently available for this tributary.


3.1.5 Crystal Creek (DPCT)

3.1.5.1 Tributary Description Crystal Creek is tributary to the Des Plaines River, and is entirely within the extent of O’Hare International Airport, which itself is entirely within the City of Chicago. This watershed has a total area of 266 acres within its DuPage County portion. Crystal Creek begins near the northern end of O’Hare’s runway 14R/22L. It follows that runway toward the southeast, also collecting portions of the western side of the airport, before pausing in a large detention facility just south of the terminal area, which is in the Cook County portion of the watershed. It then drains to the Des Plaines River after crossing under Interstate 294 just north of its Irving Park Road interchange. 3.1.5.2 Hydrologic Analysis There is no information regarding the regulatory hydrologics of Crystal Creek within the confines of DuPage County. 3.1.5.3 Hydraulic Analysis There is no information regarding the regulatory hydraulics of Crsytal Creek within the confines of DuPage County. 3.1.5.4 Flood Boundaries To reference the flood boundaries for Crystal Creek, see Map Panel: 0303. 3.1.5.5 Floodways No floodway information is currently available for this tributary. 3.1.5.6 Flood Profiles No flood profile information is currently available for this tributary.

Section printed 26 May 2004

3.1.6 Flagg Creek (DPFC)

3.1.6.1 Tributary Description Flagg Creek is a tributary to the Des Plaines River. Within the confines of DuPage County, a total watershed area of 7608 acres flows to one of several feeder branches of Flagg Creek. The DuPage County communities that contribute watershed area to Flagg Creek are Burr Ridge, Willowbrook, Hinsdale, Clarendon Hills, Westmont, Darien and Unincorporated DuPage County. This southwestern region of DuPage County is a conglomeration of many different types of development; older construction and residential communities in the north (i.e. Hinsdale and Westmont), and fast-growing development to the south (i.e. Burr Ridge and Willowbrook). But as seemingly different as these communities may be, they share in some common geographical traits within the Flagg Creek Watershed. All feeder branches modeled in DuPage County (79th Street Ditch, Plainfield Road Ditch, 63rd Street Ditch and 59th Street Ditch) flow from the west to the east. As all branches approach the county border between Cook and DuPage Counties, a steep gradient propels flow towards Flagg Creek. The 79th Street Ditch finds its headwaters on the south side of I-55 within the Village of Burr Ridge. It flows northeast, parallel to I-55, until the ditch is to the east of Grant Street. The ditch turns to the southeast passing through residential subdivisions in Burr Ridge, passes underneath Hamilton Ave, and joins the ditch on 79th Street. The ditch flows to the south on Drew Avenue for a few hundred feet then turns to the east, exiting DuPage County as it passes underneath County Line Road. The Plainfield Road Ditch is actually a ditch found somewhat to the south of Plainfield Road, but parallels Plainfield Road to a fair extent. This area of Burr Ridge is home to industrial / commercial properties. This is a simple branch that flows to the northeast, exiting DuPage County as it passes underneath County Line Road. The 63rd Street Ditch is by far the most thoroughly explored and modeled tributary for Flagg Creek watershed within the DuPage County limits. This reach proceeds from the Villages of Westmont and Clarendon Hills, passing through such areas as Johnson Slough (58th Street) and under State Route 83. All feeder branches converge around 63rd Street within the Villages of Willowbrook and Burr Ridge. And like all Flagg Creek branches within DuPage County, 63rd Street eventually exits DuPage County as it passes underneath County Line Road.


The 59th Street Ditch is a small branch that causes some flooding difficulties around Charleston Road in Hinsdale as it attempts to flow through an older subdivision. Downstream of this subdivision, the 59th Street Ditch exits the County as it passes underneath County Line Road. 3.1.6.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Flagg Creek and all its associated ditches. Harza prepared hydrologic analyses using the State Standard Method, and discharges for 10- and 100-year floods were estimated for Flagg Creek using the regional urbanized equations for Illinois (U.S. Department of the Interior, 1974). The 100-year discharges calculated by Harza were sent to the Illinois SWS for review. The discharges were approved by the SWS and certified by the DOWR. Data are located in a repository of flood-related data administered by the SWS. For each cross section of Flagg Creek, discharges for the 10- and 100-year floods were plotted on log-normal probability paper. The 50- and 500-year flood discharges were estimated by straight-line interpolation and extrapolation, respectively. The 500-year flood discharge is less reliable than the others because the period of record for discharge gages used to develop the regional urban equations is about 30 years. Harza prepared the hydrologic analysis for the 59th Street Ditch. Discharges for the 2- and 100-year floods for this stream were computed using the Illinois State Standard Method Urbanized Equations (U.S. Department of the Interior, 1974). The 100-year discharges were sent to the SWS for review. The discharges were approved by the SWS and certified by the DOWR. These data are located in a repository of flood-related data administered by the SWS. For each cross section, discharges for the 2- and 100-year floods were plotted on log-normal probability paper. The 10-, 50-, and 500-year flood discharges were estimated by straight-line interpolation and extrapolation.

Discharges for the 10-, 50-, and 100-year floods for the 63rd Street Ditch were determined using regional equations developed by the Illinois SWS. The principal factors considered in this method were soil types, land uses, watershed slope, channel slope and dimensions, and rainfall distributions (Illinois Department of Transportation, Magnitude and Frequency of Floods in Illinois, 1973). The discharges were adjusted using factors recommended by the SWS that were developed from data for the USGS gage on Flagg Creek at Willow Springs, Illinois. The 100-year flood discharges for 63rd Street Ditch and East Branch Sawmill Creek in Willowbrook were sent to the SWS for review. These discharges were approved by the SWS and certified by the DOWR for use in the State’s


floodplain regulation program. Data are located in the Illinois Floodplain Repository which is administered by the SWS. Discharges for the 10-, 50-, 100-, and 500-year floods of each flooding source studied in detail in the community are shown in Table 1. Discharges for the 10-, 50-, and 100-year floods on 79th Street Ditch and Plainfield Road Ditch were determined by Harza using regional flood-frequency equations. The parameters used were channel slope, drainage area, and the percent of urbanization and nearby gage records using methods recommended by the Illinois SWS. These methods were determined by the log-Pearson Type III analysis and the regional discharge equation at gage location (Baranecki, Vigilio, and Associates, 1977). The adjustment coefficients were developed from data for the USGS gage (No. 05533000, established in 1951), located at the 16.2-mile marker on Flagg Creek at Willow Springs, Illinois. The 100-year discharges for the streams were sent to the Illinois SWS for review. They were approved by the Illinois SWS and certified by the Illinois DWR for use in the state’s floodplain regulation program (Des Plaines River Watershed Steering Committee, 1975). Data are located in the State Floodplain Repository administered by the Illinois SWS. The flood discharges on Plainfield Road Ditch are much higher than the discharges of 79th Street Ditch because the slope of Plainfield Road Ditch is 30 percent greater than the slope of 79th Street Ditch, thereby increasing the rate of runoff. Peak discharge-drainage area relationships for the 10-, 50-, 100-, and 500-year floods of each flooding source studied in detail are presented in Table DPFC.1. Table DPFC.1: Flagg Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Flagg Creek - at mouth 18.1 1,660 2,650 3,180 4,500 - approx. 600 ft u/s 79th St Ditch 15.3 1,420 2,300 2,720 3,850 - at State Route 83 1.40 202 321 380 530 - at Eastern Ave. 0.40 101 160 190 265 Plainfield Road Ditch - at mouth 1.10 197 310 367 510 - at County Line Road 1.00 141 223 262 365 59th Street Ditch


- at County Line Road 0.51 112 183 212 293 63rd Street Ditch - at mouth 4.90 710 1,130 1,330 1,850 - at County Line Rd. 3.70 565 900 1,070 1,490 - at Madison Street 2.20 390 620 729 1,010 - at Lake Hinsdale 0.60 185 295 349 490 79th Street Ditch - at County Line Road 1.00 91 141 165 226 - at 79th Street 0.90 77 118 140 190 - at Hamilton Street 0.80 57 90 105 145 3.1.6.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. All hydraulic information for Flagg Creek and Tributaries A, B and C (tributaries found in Cook County), was obtained from the Cook County Flood Insurance Study (FEMA, Flood Insurance Study – Cook County). Cross section data for the 63rd Street Ditch were obtained from the SCS (SCS / USDA etc., Flood Plain Information Maps and Profiles, 1975) and were supplemented with data from the Improvement Plan for Burr Ridge Meadows (Baranecki, Vigilio and Associates, December 1977). Land surveys provided cross section data for the other detained studied streams. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Roughness coefficients (Manning’s “n” values” for these computations were assigned on the basis of field inspection. The range of “n” values for the streams are found in Table DPFC.2: Table DPFC.2: Flagg Creek Manning’s “n” Values



63rd Street Ditch 0.017 - 0.040 0.025 - 0.060 79th Street Ditch 0.048 - 0.055 0.032 - 0.085 Plainfield Rd Ditch 0.035 - 0.050 0.030 - 0.090 Flagg Creek 0.035 - 0.070 0.060 - 0.085 The starting water surface elevation for Flagg Creek was the 10-yr flood elevation for the Des Plaines River (SCS / USDA etc., Flood Plain


Information Maps and Profiles, 1975). Critical Depth was used for the starting water-surface elevation for 63rd Street Ditch. 79th street Ditch used the backwater for Tributary C. The starting water-surface elevation for Plainfield Road Ditch was obtained for the Indian Head Park Flood Insurance Study (HUD, Village of Indian Head Park, Illinois, December 1979). The starting water surface elevation for Tributary C were obtained from the Cook County Flood Insurance Study (FEMA, Flood Insurance Study – Cook County). Water surface elevations for floods of selected recurrence intervals were computed using the SCS WSP-2 step-backwater program (SCS / USDA, TR-61: WSP-2 Computer Program, May 1976). Mathematical relationships used in the program include the standard step-backwater procedure that estimates total energy at each cross section and accounts for frictions losses between sections using Manning’s formula. The model requires discharge, cross-section geometry, bridge geometry, starting water surface elevation, and roughness data to simulate flood flow conditions. For 59th Street Ditch studied by approximate methods, the elevation of the 100-yr flood was developed from normal depth calculations, consultation with the Village of Hinsdale Engineers, and the Hydrologic Investigation Atlas for Hinsdale (USGS, NIPC; 1964). The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevations as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during the study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. Flood Profiles were drawn showing the computed water surface elevations to an accuracy of 0.5 foot for floods of the selected recurrence intervals. See sections 3.1.5.4 and 3.1.5.6 for further details. 3.1.6.4 Flood Boundaries To reference the flood boundaries for Flagg Creek, see Map Panels: 0609, 0902, 0903, 0905, 0906, 0909 and 1003 3.1.6.5 Floodways The floodways for 63rd Street Ditch were determined from the HUD-15 computer program (U.S. Department of Agriculture, 1977). Floodways


were computed without consideration of backwater from the receiving streams. Portions of the floodway for 63rd Street Ditch lies outside of the corporate limits for the Village of Willowbrook. Please reference attached Floodway Data Tables for further information. 3.1.6.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)


BASE FLOOD WATER SURFACE ELEVATION(FEETNGVD)

WITHOUTFLOODWAY


79th Street Ditch (DPFC)DPFC0001 75 230 725 0.2 690.1 690.1 690.2 0.11

DPFC0002 355 92 127 1.3 690.5 690.5 690.6 0.11

DPFC0003 815 103 66 2.1 691.5 691.5 691.6 0.11

DPFC0004 1,678 323 499 0.3 691.6 691.6 691.7 0.11

DPFC0005 1,810 36 47 3.0 691.7 691.7 691.8 0.11

DPFC0006 2,076 36 55 2.5 692.4 692.4 692.5 0.11

DPFC0007 2,838 37 70 1.5 693.5 693.5 693.6 0.11

DPFC0008 2,981 29 45 2.3 694.0 694.0 694.1 0.11

DPFC0009 3,891 30 51 1.5 695.2 695.2 695.3 0.11


AND INCORPORATED AREAS 79TH STREET DITCH (DPFC)

In feet above county boundary1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Plainfield Road Ditch (DPFC)

DPFC0010 109 286 3,050 0.1 693.3 693.3 693.4 0.11

DPFC0011 1,119 53 245 0.8 693.3 693.3 693.4 0.11

DPFC0012 1,164 63 323 0.6 695.6 695.6 695.6 0.01

DPFC0013 1,799 64 404 0.4 695.6 695.6 695.6 0.01

DPFC0014 2,043 35 67 2.4 696.8 696.8 696.8 0.01

DPFC0015 2,123 65 102 1.6 696.9 696.9 697.0 0.11

DPFC0016 2,448 75 95 1.6 697.3 697.3 697.3 0.01

DPFC0017 2,808 34 39 2.9 698.7 698.7 698.7 0.01

DPFC0018 3,108 32 50 2.3 699.3 699.3 699.3 0.01

DPFC0019 3,398 27 61 1.8 699.5 699.5 699.5 0.01

DPFC0020 3,708 80 333 0.3 701.4 701.4 701.4 0.01

DPFC0021 3,958 34 101 1.0 701.4 701.4 701.4 0.01

DPFC0022 4,185 265 1,220 0.1 702.0 702.0 702.0 0.01

DPFC0023 4,351 159 846 0.1 704.5 704.5 704.5 0.01

DPFC0024 4,689 17 55 1.9 705.2 705.2 705.2 0.01

DPFC0025 4,904 23 71 1.2 705.3 705.3 705.3 0.01

DPFC0026 5,394 330 372 0.2 705.3 705.3 705.3 0.01


AND INCORPORATED AREAS PLAINFIELD ROAD DITCH (DPFC)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Plainfield Road Ditch (DPFC)

DPFC0027 5,898 53 23 0.7 705.6 705.6 705.7 0.11

DPFC0028 6,068 35 20 0.9 705.8 705.8 705.8 0.01


AND INCORPORATED AREAS PLAINFIELD ROAD DITCH (DPFC)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


63rd Street Ditch (DPFC)

DPFC0029 1,037 110 253 3.2 670.6 670.6 670.6 0.01

DPFC0030 3,571 50 181 2.9 675.2 675.2 675.2 0.01

DPFC0031 4,762 100 546 1.9 683.3 683.3 683.3 0.01

DPFC0032 8,337 83 178 4.1 701.8 701.8 701.9 0.11

DPFC0033 9,755 67 242 3.0 712.0 712.0 712.1 0.11

DPFC0034 10,284 288 870 0.8 714.4 714.4 714.5 0.11

DPFC0035 12,650 200 709 0.5 723.8 723.8 723.9 0.11


AND INCORPORATED AREAS 63RD STREET DITCH (DPFC)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Flagg Creek (DPFC)DPFC0036 48,845 83 314 1.2 712.3 712.3 712.4 0.11

DPFC0037 49,244 34 108 3.1 713.5 713.5 713.6 0.11

DPFC0038 49,796 26 102 2.8 715.7 715.7 715.8 0.11

DPFC0039 50,360 72 190 1.1 718.6 718.6 718.7 0.11 2


AND INCORPORATED AREAS FLAGG CREEK (DPFC)

In feet above mouth2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


59th Street Ditch (DPFC)DPFC0040 225 32 123 1.7 671.2 671.2 671.3 0.11

DPFC0041 960 13 25 7.8 675.2 675.2 675.3 0.11

DPFC0042 1,250 42 60 3.1 677.2 677.2 677.3 0.11

DPFC0043 1,475 15 37 4.8 678.3 678.3 678.4 0.11


AND INCORPORATED AREAS 59TH STREET DITCH (DPFC)


TAB

LE 5

665

670

675 675

680 680

685 685

690 690

695 695

700 700

0 500 1000 1500 2000 2500 3000 3500 4000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE COUNTY BOUNDARY

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

79TH

STR

EET

DITC

H (D

PFC)

16P

DPFC

0001

DPFC

0002

DPFC

0003

DPFC

0004

DPFC

0005

DPFC

0006

DPFC

0007

DPFC

0008

DPFC

0009

COUN

TY L

INE

ROAD

DREW

AVE

NUE

79TH

STR

EET

HAM

ILTO

N AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

500-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


COUN

TY B

OUND

ARY

670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

-500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PLAI

NFIE

LD R

OAD

DITC

H (D

PFC)

17P

DPFC

0010

DPFC

0011

DPFC

0012

DPFC

0013

DPFC

0014

DPFC

0015

DPFC

0016

DPFC

0017

DPFC

0018

DPFC

0019

DPFC

0020

DPFC

0021

DPFC

0022

DPFC

0023

DPFC

0024

DPFC

0025

COUN

TY B

OUND

ARY

COUN

TY L

INE

ROAD

FIEL

DSTO

NE D

RIVE

INTE

RNAT

IONA

L HA

RVES

TER

ENTR

ANCE

WEI

R

WEI

R

INTE

RNAT

IONA

L ST

REET

COM

MER

CE S

TREE

T

UNNA

MED

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERTS

CULVERT

CULVERTS

UNNA

MED

ROA

D

50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR PROFILETO BE SHOWN SEPARATELY

695

700

705 705

710 710

5000 5500 6000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PLAI

NFIE

LD R

OAD

DITC

H (D

PFC)

18P

DPFC

0026

DPFC

0027

DPFC

0028

UNNA

MED

ROA

D

LIM

IT O

F PR

OFIL

E*


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

6500* PROFILE INFORMATION NOT AVAILABLE UPSTREAM OF THIS POINT

655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

63RD

STR

EET

DITC

H (D

PFC)

19P

DPFC

0029

DPFC

0030

DPFC

0031

COUN

TY B

OUND

ARY

COUN

TY L

INE

ROAD

ELM

STR

EET

GARF

IELD

AVE

NUE

WOO

DEN

FOOT

BRID

GEGR

ANT

AVEN

UEW

EIR

UNNA

MED

TRI

BUTA

RY A

LEGEND500-YEAR FLOOD*

100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


CULVERT

CONF

LUEN

CE O

F

*DATA NOT AVAILABLE DOWNSTREAM OF 7,066 FEET

680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

63RD

STR

EET

DITC

H (D

PFC)

20P

DPFC

0032

DPFC

0033

DPFC

0034

DPFC

0035

MAD

ISON

STR

EET

LANE

COU

RT

ROBE

RT K

INGE

RY H

IGHW

AY

LAKE

HIN

SDAL

E DR

IVE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE DOWNSTREAM OF 7,066 FEET

STAT

E RO

UTE

83/

702

704

706 706

708 708

710 710

712 712

714 714

716 716

718 718

720 720

48600 48800 49000 49200 49400 49600 49800 50000 50200 50400 50600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FLAG

G CR

EEK

(DPF

C)

21P

DPFC

0036

DPFC

0037

DPFC

0038

DPFC

0039

LIM

IT O

F DE

TAIL

ED S

TUDY

STAT

E RO

UTE

83/

ANN

STRE

ET

FOOT

BRID

GEPR

IVAT

E DR

IVE

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

FOOT

BRID

GE

HARR

IS A

VENU

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

EPR

IVAT

E DR

IVE

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50- AND 100-YEAR FLOOD PROFILESARE TOO CLOSE TO BE SHOWN SEPARATELY

ROBE

RT K

INGE

RY H

IGHW

AY

655

660

665 665

670 670

675 675

680 680

0 250 500 750 1000 1250 1500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

59TH

STR

EET

DITC

H (D

PFC)

22P

DPFC

0040

DPFC

0041

DPFC

0042

DPFC

0043

COUN

TY B

OUND

ARY

COUN

TY L

INE

ROAD

CHAR

LEST

ON R

OAD

NORT

H

CHAR

LEST

ON R

OAD

SOUT

H

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.1.7 Willow Creek (DPWL)

3.1.7.1 Tributary Description Willow Creek is a tributary to the Des Plaines River, which can be located as the watershed immediately to the north of Bensenville Ditch. Within the confines of DuPage County, the total watershed area for Willow Creek totals 3257 acres. The communities that feed watershed area into Willow Creek are Unincorporated DuPage County, Elk Grove Village, Bensenville and the City of Chicago. Willow Creek drains from west to east, starting in an older residential section of DuPage County, west of Kingery Highway (Route 83). After passing under Kingery Highway, the stream enters the Village of Bensenville and an area of large commercial buildings used primarily for the storage of goods arriving and departing from O’Hare Airport. Once beyond these commercial zones, Willow Creek enters the confines of O’Hare Airport. 3.1.7.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Willow Creek. Peak discharges for Willow Creek, which does not have a streamflow gage, were determined using the HEC-1 computer program (USCOE, HEC-1 Hydrograph Package 723-X6-L2010) and the SCS hydrograph feature of the HEC-1 model (SCS, National Engineering Handbook, Section 4 “Hydrology”). Peak Discharges for the Addison Creek Tributaries were computed using the TR-20 computer program (SCS, Technical Release No. 20 – Computer Program for Project Formulation, Hydrology). The 500-year peak discharge was determined using a linear extrapolation preformed on probability paper. Peak discharge-drainage area relationships for the 10-, 50-, 100-, and 500-year floods of each flooding source studied in detail are presented in the Table DPWL.1. Table DPWL.1: Willow Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Willow Creek

Section printed 9 September 2004

- at York Road 1.68 426 736 915 1,421 - at d/s end of culvert 1.12 202 346 429 693

3.1.7.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Roughness coefficients (Manning’s “n”) were assigned based on doled inspection, photographs, and engineering judgment (USGS, Roughness Characteristics of Natural Channels; Chow, Open Channel Hydraulics). Roughness values range from 0.030 to 0.075 for the channels and from 0.030 to 0.095 for the overbanks. Water-surface elevations for floods of the selected recurrence intervals on Willow Creek were computed using the HEC-2 step-backwater computer program (USCOE, HEC-2Water Surface Profiles 723-X6-L202A). Starting water-surface elevations for those creeks were determined by performing a routing at restrictive culverts that cause ponding at York Road and the Chicago and North Western railroad embankment. The ponding area is just east of the study area. Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. In cases where the 50- and 100-year flood elevations are close together, due to limitations of the profile scale, only the 100-year profile has been shown. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.1.7.4 Flood Boundaries


To reference the flood boundaries for Willow Creek, see Map Panels: 0302, 0303, 0305 and 0306 3.1.7.5 Floodways Please reference attached Floodway Data Tables for further information. 3.1.7.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


South Unnamed Creek (DPWL)

DPWL0001 34,291 200 597 1.5 662.1 662.1 662.1 0.01

DPWL0002 35,900 299 1,018 0.8 666.4 666.4 666.4 0.01

DPWL0003 37,357 206 629 1.3 666.7 666.7 666.7 0.01 2

DPWL0004 37,517 110 309 2.7 666.8 666.8 666.8 0.01

DPWL0005 38,248 57 193 2.2 669.1 669.1 669.2 0.11

DPWL0006 39,051 204 692 0.6 669.4 669.4 669.5 0.11

DPWL0007 39,811 317 831 0.5 669.4 669.4 669.5 0.11


AND INCORPORATED AREAS SOUTH UNNAMED CREEK (DPWL)


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


North Unnamed Creek (DPWL)

DPWL0008 33,672 409 732 2.2 663.8 663.8 663.8 0.01 2

DPWL0009 33,952 208 467 0.9 664.3 664.3 664.3 0.01

DPWL0010 35,922 560 121 2.7 665.8 665.8 665.8 0.01

DPWL0011 36,122 190 178 1.6 666.5 666.5 666.5 0.01


AND INCORPORATED AREAS NORTH UNNAMED CREEK (DPWL)


1

TAB

LE 5

640

645

650 650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

33315 33815 34315 34815 35315 35815 36315 36815 37315 37815 38315 38815 39315 39815

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SOUT

H UN

NAM

ED C

REEK

(DPW

L)

23P

DPW

L000

1

DPW

L000

2

DPW

L000

3

DPW

L000

4

DPW

L000

5

DPW

L000

6

DPW

L000

7

LIM

IT O

F DE

TAIL

ED S

TUDY

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

THOR

NDAL

E AV

ENUE

THOM

AS D

RIVE

RAIL

ROAD

FAIR

WAY

DRI

VE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


640

645

650 650

655 655

660 660

665 665

670 670

33000 33500 34000 34500 35000 35500 36000 36500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

NORT

H UN

NAM

ED C

REEK

(DPW

L)

24P

DPW

L000

8

DPW

L000

9

DPW

L001

0

DPW

L001

1LI

MIT

OF

DETA

ILED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

3.2 DuPage River (DU)

3.2.1 Lily Cache (DULC)

3.2.1.1 Tributary Description Lily Cache Creek has only a small watershed area (1180 acres) within the confines of DuPage County. Nearly the entire watershed area within DuPage County is residential, the primary branch starting in the headwaters within the Village of Darien on the west side of Lemont Road. This branch proceeds to the west in a serpentine motion, entering the Village of Woodridge and passing under Cambridge Road. The branch turns to the south and exits DuPage County. A second Lily Cache Branch begins in a quickly developing part of Woodridge and Unincorporated DuPage County (found to the south of the first branch). Many of these lands are still in an open state and are likely to stay that way for some time as development is in the form of parks and schools. As this branch proceeds to the west, only one recently developed subdivision is encountered. The branch passes under Woodward Avenue and flows to the west exiting DuPage County. 3.2.1.2 Hydrologic Analysis

There is no information regarding the regulatory hydrologics of Lily Cache Creek within the confines of DuPage County. 3.2.1.3 Hydraulic Analysis There is no information regarding the regulatory hydraulics of Lily Cache Creek within the confines of DuPage County.

3.2.1.4 Flood Boundaries To reference the flood boundaries for Lily Cache, see Map Panels: 0809, 0907 and 1001. 3.2.1.5 Floodways No floodway information is currently available for this tributary. 3.2.1.6 Flood Profiles No flood profile information is currently available for this tributary.


3.2.2 Spring Brook #2 (DUSG)

3.2.2.1 Tributary Description Spring Brook #2 is tributary to the DuPage River. The total watershed area found within DuPage County associated with Spring Brook #2 is 8033 acres. This area, comprised of the municipalities of Aurora and Naperville and unincorporated DuPage County, has undergone rapid developmental growth in recent decades, and is continuing to change land use characteristics. There are three main feeder branches that make up the Spring Brook #2 Tributary. The first branch finds its headwater area in an older residential neighborhood within the City of Naperville, beginning near the Fox Valley Mall area. This branch winds its way west, eventually curving to the residential south passing under Route 34, Oswego Ave, Rickert Drive, and 75th Street where it meets the second Spring Brook #2 feeder branch. Beginning in Aurora, approximately one mile west of Route 59 and about one mile south of 75th Street, the second feeder branch proceeds out of an older residential subdivision on a northeast bearing. It passes through a square mile area of unincorporated land that is still relatively undeveloped, and proceeds into the northwestern quadrant of the Springbrook Prairie. Still on this northeastern track, this branch joins the first feeder branch south of 75th Street and takes an abrupt turn to the south. The branch continues to wind its way through the prairie, crossing Book Road two times, when it joins the third feeder branch. The third feeder, in many respects is very similar to the second feeder tributary in that the headwaters are found in older, residential Aurora, and that it proceeds on a northeast track. The starting location of this branch is one half mile south of Montgomery Road and one mile west of Route 59. As the branch proceeds east, it passes under Route 59 and through a newly developed piece of the City of Naperville. One mile downstream, this branch joins the second feeder branch within the Springbrook Prairie Forest Preserve. Spring Brook #2 continues on a serpentine-like path through the forest preserve heading in a southerly bearing. The stream exits Springbrook Prairie Forest Preserve and DuPage County. Spring Brook #2 joins with the DuPage River in Will County just downstream of the East and West Branch DuPage River junction. 3.2.2.2 Hydrologic Analysis


Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Spring Brook #2. Discharges for the 10-year, 50-year, and 100-year floods for Spring Brook No. 2 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table DUSG.1

Table DUSG.1: Spring Brook #2 Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Spring Brook #2

- at river mile 2.781 9.99 545 825 960 1,290 - approx. 1,660 ft u/s

of 75th Street 3.30 190 330 400 600

3.2.2.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Roughness coefficients (Manning’s “n” values” for these computations were assigned on the basis of field inspection. The range of “n” values for the streams are found in Table DUSG.2: Table DUSG.2: Spring Brook #2 Manning’s “n” Values




Spring Brook #2 0.035 0.035 A small portion of Spring Brook #2 southwest of the City of Naperville between 87th and 95th Streets was also studied by approximate analysis. Depth of the 100-year flood at this location was calculated from a stage-frequency curve prepared for a USGS crest stage gage at 83rd Street. Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. In cases where the 50- and 100-year flood elevations are close together, due to limitations of the profile scale, only the 100-year profile has been shown. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.2.2.4 Flood Boundaries To reference the flood boundaries for Spring Brook #2, see Map Panels: 0705, 0706, 0707, 0708, 0709 and 0807 3.2.2.5 Floodways Please reference attached Floodway Data Tables for further information. 3.2.2.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Spring Brook No. 2 (DUSG)

DUSG0001 17,272 133 679 1.4 657.0 657.0 657.1 0.11

DUSG0002 21,142 195 363 2.6 659.0 659.0 659.1 0.11

DUSG0003 25,700 133 946 1.0 668.5 668.5 668.6 0.11

DUSG0004 28,095 362 1,667 0.6 668.7 668.7 668.8 0.11

DUSG0005 31,715 227 448 1.6 671.5 671.5 671.6 0.11

DUSG0006 34,208 300 923 0.8 675.3 675.3 675.4 0.11

DUSG0007 39,330 855 3,064 0.1 681.8 681.8 681.9 0.11

DUSG0008 40,832 135 335 1.1 682.0 682.0 682.1 0.11

DUSG0009 42,286 87 286 1.3 682.3 682.3 682.4 0.11

DUSG0010 42,441 228 210 1.7 684.5 684.5 684.6 0.11

DUSG0011 44,308 120 376 0.5 684.9 684.9 685.0 0.11

DUSG0012 45,425 251 525 0.4 685.0 685.0 685.1 0.11

DUSG0013 45,578 256 1,256 0.2 687.1 687.1 687.2 0.11

DUSG0014 48,418 113 250 0.6 687.2 687.2 687.3 0.11


AND INCORPORATED AREAS SPRING BROOK NO. 2 (DUSG)

In feet above confluence with West Branch DuPage River1

TAB

LE 5

640

645

650 650

655 655

660 660

665 665

17000 17500 18000 18500 19000 19500 20000 20500 21000 21500 22000 22500 23000 23500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WEST BRANCH DUPAGE RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

2 (D

USG)

25P

DUSG

0001

DUSG

0002

COUN

TY B

OUND

ARY

87TH

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


650

655

660 660

665 665

670 670

23500 24000 24500 25000 25500 26000 26500 27000 27500 28000 28500 29000 29500 30000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

2 (D

USG)

26P

DUSG

0003

DUSG

0004

NAPE

RVIL

LE R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


655

660

665 665

670 670

675 675

680 680

30000 30500 31000 31500 32000 32500 33000 33500 34000 34500 35000 35500 36000 36500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

2 (D

USG)

27P

DUSG

0005

DUSG

0006

83RD

STR

EET

83RD

STR

EET

BOOK

ROA

D

BOOK

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


665

670

675 675

680 680

685 685

690 690

36500 37000 37500 38000 38500 39000 39500 40000 40500 41000 41500 42000 42500 43000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

2 (D

USG)

28P

DUSG

0007

DUSG

0008

DUSG

0009

DUSG

0010

75TH

STR

EET

RICK

ERT

DRIV

E

OAKT

ON L

ANE

WEI

R


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


SPRING BROOK/ COUNTRYSIDE LAKE

CULVERT

CULVERT

670

675

680 680

685 685

690 690

43000 43500 44000 44500 45000 45500 46000 46500 47000 47500 48000 48500 49000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

2 (D

USG)

29P

DUSG

0011

DUSG

0012

DUSG

0013

DUSG

0014

SEQU

OIA

ROAD

OSW

EGO

ROAD

WHI

SPER

ING

HILL

S DR

IVE

OGDE

N AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


COUNTRYSIDE LAKESPRING BROOK/

LAKE OSBORNE

CULVERTCULVERT CULVERT

3.3 East Branch DuPage River (EB)

3.3.1 Main Stem (EBEB)

3.3.1.1 Tributary Description The Main Stem of the East Branch DuPage River has its headwaters in the Village of Bloomingdale, specifically Westlake Park. The East Branch takes a southern route passing through communities such as Bloomingdale, Glendale Heights, Glen Ellyn, Lombard, Lisle, Woodridge and Unincorporated DuPage County. Additional communities such as Addison, Wheaton, Naperville and Bolingbrook contribute watershed area to the East Branch DuPage River Main Stem. The total watershed area tributary to the East Branch DuPage River Main Stem is 21512 acres. As the East Branch Main Stem proceeds from Westlake Park in Bloomingdale, it passes under Glen Ellyn Road, Brookdale Drive, Army Trail Road, the CCP Rail Road embankment, North Avenue, St. Charles Road, Crescent Boulevard, Hill Avenue, The Illinois Prairie Path, Route 53 (North), Roosevelt Road (Route 38), Butterfield Road (Route 56), Route 53 (South), Warrenville Road, I-88 (the East-West Tollway), Ogden Avenue, Burlington Avenue, the Burlington Northern Railroad bridge, Short Street, Maple Avenue, Four Lakes Avenue, Summerhill Drive, Hobson Avenue, and 75th Street within the confines of DuPage County. The East Branch proceeds through Royce Road before confluencing the West Branch DuPage River in Will County. The East Branch DuPage River Main Stem watershed has some natural buffer areas to protect the floodplain area through the placement of Forest Preserves and parks. Such areas found on the main stem are: West Lake Park, Sunnyside Park, the East Branch Forest Preserve, Ackerman Park, Churchill Woods Forest Preserve, Glen Oak County Club, Western Acres Golf Course, Lisle Community Park, River Bend Golf Course, Seven Bridges Golf Course, and Green Valley Forest Preserve. Outside of these preserve areas, the primary land use is residential. 3.3.1.2 Hydrologic Analysis Discharge-frequency data for East Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the


HEC-1 model of the DuPage River Basin to determine the 10-year, 50-

year, and 100-year peak discharges (U.S. Department of Commerce,

1963).

The 500-year peak discharge was determined from a linear extrapolation

of a log-probability curve for the 10-, 50-, and 100-year values.

The USGS stream gages used for the hydrologic analyses of the East

Branch DuPage River studied in detail in the Unincorporated Areas of

DuPage County, Illinois, are presented in Table EBEB.1 below:

Table EBEB.1: USGS Stream Gages Used for Hydrologic Analysis of the East Branch DuPage River

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) East Branch DuPage

River at Lisle 05540230 58.3 21

East Branch DuPage

River at Naperville 05540130 123.0 1

A summary of the drainage area-peak discharge relationships for the

portions of the streams studied by detailed methods is shown in Table

EBEB.2

Table EBEB.2 East Branch DuPage River Summary of Discharges


Flooding Source Drainage Peak Discharges (cfs)

And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr

East Branch DuPage

River

- at river mile 30.6 80.1 2,000 2,910 3,375 4,700

- just d/s of Crabtree

Creek 75.3 1,850 2,630 3,080 4,270

- at Hobson Road Br. 71.1 1,840 2,600 3,015 4,175

- at Maple Avenue 58.3 1,810 2,510 2,900 3,880

- at East-West Tollway 40.1 1,370 1,850 2,200 2,890

- at Butterfield Rd. 27.2 1,010 1,325 1,630 2,090

- at Glen Ellyn Sewage

Disposal Plant 22.9 885 1,150 1,435 1,820

- at St. Charles Rd. 14.2 610 760 990 1,220

- above confluence w/

Armitage Creek 6.4 280 330 350 410

3.3.1.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the source studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for East Branch DuPage River were obtained by field measurement.

The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Roughness coefficients (Manning’s “n”) for East Branch DuPage River were estimated by field inspection at the various cross sections. Table EBEB.3 shows the channel and overbank “n” values for the streams studied by detailed methods. Table EBEB.3: East Branch DuPage River Manning’s “n” Values



East Branch DuPage River 0.035 - 0.055 0.055 - 0.090 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.1.4 Flood Boundaries


To reference the flood boundaries for East Branch DuPage River Main Stem, see Map Panels: 0205, 0206, 0208, 0209, 0307, 0502, 0503, 0505, 0506, 0508, 0509, 0601, 0602, 0604, 0605, 0607, 0802, 0803, 0805, 0806, 0808 and 0809 3.3.1.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.1.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch DuPage River (EBEB)

EBEB0001 39,546 698 2,239 1.4 652.3 652.3 652.4 0.11

EBEB0002 42,553 140 876 3.4 655.1 655.1 655.2 0.11

EBEB0003 46,276 267 1,636 1.8 657.9 657.9 658.0 0.11

EBEB0004 51,841 530 3,001 1.0 660.2 660.2 660.2 0.01

EBEB0005 54,164 113 623 4.7 662.1 662.1 662.2 0.11

EBEB0006 55,725 110 694 4.2 663.3 663.3 663.3 0.01

EBEB0007 56,177 171 736 3.9 663.7 663.7 663.8 0.11

EBEB0008 58,385 857 2,852 1.0 664.5 664.5 664.6 0.11

EBEB0009 58,527 857 2,871 1.0 664.5 664.5 664.6 0.11

EBEB0010 59,387 296 3,884 0.6 665.0 665.0 665.1 0.11

EBEB0011 60,050 90 728 4.0 665.7 665.7 665.7 0.01

EBEB0012 60,231 135 487 6.0 665.8 665.8 665.8 0.01

EBEB0013 61,326 119 776 3.7 668.1 668.1 668.1 0.01

EBEB0014 62,802 106 787 3.7 669.2 669.2 669.2 0.01

EBEB0015 64,011 205 1,366 1.6 670.4 670.4 670.4 0.01

EBEB0016 64,347 531 2,323 0.9 670.5 670.5 670.6 0.11

EBEB0017 65,098 569 3,182 0.7 670.6 670.6 670.7 0.11


AND INCORPORATED AREAS EAST BRANCH DUPAGE RIVER (EBEB)

In feet above confluence with West Branch DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



EBEB0018 66,245 273 1,368 1.6 671.0 671.0 671.1 0.11

EBEB0019 67,569 535 2,234 1.0 671.6 671.6 671.7 0.11

EBEB0020 70,769 516 2,399 0.9 673.8 673.8 673.9 0.11

EBEB0021 72,500 122 653 3.4 674.3 674.3 674.4 0.11

EBEB0022 74,465 368 1,600 1.4 676.4 676.4 676.4 0.01

EBEB0023 76,235 1,030 1,667 1.3 676.7 676.7 676.8 0.11 2

EBEB0024 77,448 200 387 5.7 676.8 676.8 676.9 0.11

EBEB0025 77,785 160 797 2.0 677.3 677.3 677.4 0.11

EBEB0026 80,229 1,008 2,662 0.6 678.4 678.4 678.4 0.01

EBEB0027 83,043 55 273 5.3 680.3 680.3 680.4 0.11

EBEB0028 83,918 60 346 4.1 682.1 682.1 682.2 0.11

EBEB0029 85,337 743 2,597 0.6 682.8 682.8 682.9 0.11

EBEB0030 87,732 460 1,760 0.8 683.4 683.4 683.5 0.11

EBEB0031 89,169 117 605 2.4 684.5 684.5 684.6 0.11

EBEB0032 90,156 658 2,629 0.5 684.9 684.9 685.0 0.11

EBEB0033 91,769 790 770 1.9 686.7 686.7 686.8 0.11

EBEB0034 92,385 759 2,763 0.5 686.9 686.9 687.0 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



EBEB0035 94,068 544 2,361 0.6 687.0 687.0 687.1 0.11

EBEB0036 97,486 128 481 3.0 687.6 687.6 687.7 0.11

EBEB0037 98,482 79 341 4.2 689.8 689.8 689.8 0.01 2

EBEB0038 99,487 840 642 2.2 691.6 691.6 691.7 0.11

EBEB0039 101,248 690 3,480 0.4 691.8 691.8 691.9 0.11

EBEB0040 106,067 329 928 1.1 692.5 692.5 692.6 0.11

EBEB0041 108,486 338 399 2.5 693.6 693.6 693.7 0.11

EBEB0042 113,097 62 133 2.6 697.7 697.7 697.8 0.11

EBEB0043 116,118 29 130 2.7 700.6 700.6 700.7 0.11

EBEB0044 117,099 57 91 3.9 702.0 702.0 702.1 0.11

EBEB0045 118,935 1,143 6,429 0.1 710.5 710.5 710.6 0.11

EBEB0046 122,553 692 3,198 0.1 712.2 712.2 712.3 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch Tributary No. 3 (EBEB)

EBEB0047 684 164 239 1.4 670.2 670.2 670.2 0.01 2

EBEB0048 1,013 84 97 3.4 674.9 674.9 674.9 0.01 2

EBEB0049 1,426 110 273 1.2 686.0 686.0 686.1 0.11

EBEB0050 1,754 57 126 2.6 686.1 686.1 686.2 0.11

EBEB0051 1,890 57 62 5.2 686.5 686.5 686.5 0.01

EBEB0052 2,613 125 264 1.2 699.1 699.1 699.2 0.11

EBEB0053 3,263 119 198 1.1 713.7 713.7 713.7 0.01


AND INCORPORATED AREAS

EAST BRANCH TRIBUTARY NO. 3 (EBEB) [SCHWARTZ CREEK]

In feet above confluence with East Branch DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain Actual f

1

TAB

LE 5

625

630

635 635

640 640

645 645

650 650

655 655

660 660

33000 34000 35000 36000 37000 38000 39000 40000 41000 42000 43000 44000 45000 46000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

36P

EBEB

0001

EBEB

0002

COUN

TY B

OUND

ARY

CONF

LUEN

CE O

F CR

ABTR

EE C

REEK

75TH

STR

EET

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 7


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F

635

640

645 645

650 650

655 655

660 660

665 665

670 670

46000 47000 48000 49000 50000 51000 52000 53000 54000 55000 56000 57000 58000 59000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

37P

EBEB

0003

EBEB

0004

EBEB

0005

EBEB

0006

EBEB

0007

EBEB

0008

EBEB

0009

HOBS

ON R

OAD

& C

ONFL

UENC

E W

ITH

PREN

TISS

CRE

EK

WEI

R

CONF

LUEN

CE O

F ST

. PRO

COPI

US C

REEK

SUM

MER

HILL

DRI

VE

FOUR

LAK

ES A

VENU

E

MAP

LE A

VENU

E

SHOR

T ST

REET

CONF

LUEN

CE O

F RO

TT C

REEK


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

59000 60000 61000 62000 63000 64000 65000 66000 67000 68000 69000 70000 71000 72000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

38P

EBEB

0010

EBEB

0011

EBEB

0012

EBEB

0013

EBEB

0014

EBEB

0015

EBEB

0016

EBEB

0017

EBEB

0018

EBEB

0019

EBEB

0020

RAIL

ROAD

BURL

INGT

ON A

VENU

E

U.S.

HIG

HWAY

34

(OGD

EN A

VENU

E)CO

NFLU

ENCE

OF

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 3CO

NFLU

ENCE

OF

ST. J

OSEP

H CR

EEK

LACE

Y AV

ENUE

MID

DLET

ON A

VENU

E

EAST

- W

EST

TOLL

WAY

(I-8

8)

WAR

RENV

ILLE

ROA

D

ARBO

RETU

M R

OAD

CONF

LUEN

CE O

F EA

SH B

RANC

H TR

IBUT

ARY

NO. 5

ARBO

RETU

M R

OAD

STAT

E RO

UTE

53


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


650

655

660 660

665 665

670 670

675 675

680 680

685 685

72000 73000 74000 75000 76000 77000 78000 79000 80000 81000 82000 83000 84000 85000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

39P

EBEB

0021

EBEB

0022

EBEB

0023

EBEB

0024

EBEB

0025

EBEB

0026

EBEB

0027

EBEB

0028

CONF

LUEN

CE O

F LA

CEY

CREE

K

(STA

TE R

OUTE

56)

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 4TR

EATM

ENT

PLAN

T RO

AD

STRE

AM N

ORTH

OF

22ND

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


BUTT

ERFI

ELD

ROAD

CONF

LUEN

CE O

F

CONF

LUEN

CE O

F UN

NAM

ED

660

665

670 670

675 675

680 680

685 685

690 690

85000 86000 87000 88000 89000 90000 91000 92000 93000 94000 95000 96000 97000 98000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

40P

EBEB

0029

EBEB

0030

EBEB

0031

EBEB

0032

EBEB

0033

EBEB

0034

EBEB

0035

EBEB

0036

ROOS

EVEL

T RO

AD

STAT

E RO

UTE

53


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

715 715

98000 99000 100000 101000 102000 103000 104000 105000 106000 107000 108000 109000 110000 111000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

41P

EBEB

0037

EBBE

0038

EBEB

0039

EBEB

0040

EBEB

0041

ILLI

NOIS

PRA

IRIE

PAT

H (M

AIN

STEM

)

HILL

AVE

NUE

CRES

CENT

BOU

LEVA

RD

ST. C

HARL

ES R

OAD

ABAN

DONE

D RA

ILRO

AD CONF

LUEN

CE O

F EA

ST B

RANC

H TR

IBUT

ARY

NO. 2

CONF

LUEN

CE O

F EA

ST B

RANC

H TR

IBUT

ARY

NO. 1

NORT

H AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


680

685

690 690

695 695

700 700

705 705

710 710

715 715

111000 112000 113000 114000 115000 116000 117000 118000 119000 120000 121000 122000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

42P

EBEB

0042

EBEB

0043

EBEB

0044

EBEB

0045

CONF

LUEN

CE O

F AR

MIT

AGE

DITC

H

RAIL

ROAD

SWIF

T M

EADO

WS

TRIB

UTAR

Y


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


TOP OF RAIL = 739.0

CONF

LUEN

CE O

F

695

700

705 705

710 710

715 715

720 720

122000 123000 124000 125000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

DUPA

GE R

IVER

(EBE

B)

43P

EBEB

0046

ARM

Y TR

AIL

ROAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH EAST BRANCH DUPAGE RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH.

TRI

BUTA

RY N

O. 3

(EBE

B)

47P

EBEB

0047

EBEB

0048

EBEB

0049

EBEB

0050

EBEB

0051

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

TWIN

CUL

VERT

S TH

ROUG

H LE

VEE

RIVE

R DR

IVE

PARK

ING

LOT

CROS

SING

SWAR

TZ A

VENU

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRI

VE

DEVO

N AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROMEAST BRANCH DUPAGE RIVER

CULVERT

680

685

690 690

695 695

700 700

705 705

710 710

715 715

2200 2400 2600 2800 3000 3200 3400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH.

TRI

BUTA

RY N

O. 3

(EBE

B)

48P

EBEB

0052

EBEB

0053

WIN

CHES

TER

AVEN

UE

MID

DLET

ON A

VENU

ELI

MIT

OF

DETA

ILED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.2 Armitage Creek (EBAR)

3.3.2.1 Tributary Description Armitage Creek is located in DuPage County in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Armitage Creek Watershed covers approximately 2.13 square miles in Glendale Heights, Bloomingdale, and unincorporated Bloomingdale Township, as shown in Figures 2-1 and 2-2. Armitage Creek flows into the main channel of the East Branch DuPage River approximately 1,400 feet north of North Avenue (Illinois State Route 64). The drainage system consists of 2.2 miles of the main stem of Armitage Creek and 0.8 miles of Armitage Fork tributary. The main stem of Armitage Creek originates at Glen Point Business Park detention ponds, located west of Bloomingdale Road, and flows generally to the southeast towards the East Branch DuPage River. The creek channel between Paul Avenue and Lincoln Avenue (approximately 1,400 feet) and the channel between Armitage Avenue and Wayne Avenue (approximately 2,070 feet) are enclosed. The Armitage Fork tributary begins at the outfall east of Bloomingdale Road. This tributary travels westward and joins the mainstem of Armitage Creek just north of Winthrop Avenue. Downstream of Pearl Avenue, the in-bank creek channel is lined with concrete; this segment extends for approximately 1,500 feet to the confluence with the main stem. 3.3.2.2 Hydrologic Analysis For Armitage Tributary, flood flow frequency data were developed through use of the State of Illinois multiple regression equations (IDOT, Magnitude and Frequency of Floods in Illinois, 1973). This method utilizes regional equations developed from known flood-frequency curves, which relate flood peak discharges to recurrence intervals of 1.25, 2, 5, 10, 25, 50, and 100 years using drainage area, main channel slope, rainfall intensity, and a regional factor as independent variables. For Armitage Fork and the upstream reach of Armitage Ditch, peak discharges were derived by comparison of drainage areas to the main stem. The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. Drainage area peak discharge relationships for Armitage Tributary are shown in Table EBAR.1. Table EBAR.1 Armitage Creek Summary of Discharges



Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr East Branch DuPage

- above confluence w/ Armitage Creek 6.4 280 330 350 410

Armitage Creek - at Mouth 2.1 320 550 715 1,420

- above confluence w/ Armitage Fork 0.8 195 325 435 865

- at Ardmore Avenue 0.4 140 235 305 605 - above Placid Avenue 0.2 60 135 225 540 Armitage Fork - at Mouth 0.7 185 315 415 820

3.3.2.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the source studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross sections for he backwater analyses of the East Branch DuPage River were field surveyed; for Armitage Creek and Armitage Fork, channel sections were field surveyed, with the overbank sections taken from topographic maps at a scale of 1:9,600, with a contour interval of four feet (Ralph F. Gross and Son, Assoc., Inc., Village of Glendale Heights Comprehensive Storm Drainage Report, Nov 1973). In all cases, cross sections were located at close intervals above and below bridges and culverts in order to compute the significant backwater effects of these structures in the highly urbanized areas. Locations of selected cross sections used in the hydraulic analyses are shown on in the Flood Profiles section 3.3.2.6. Channel roughness factors (Manning’s “n”) for these computations were assigned on the basis of field inspection of flood plain areas. Roughness values varied for each stream studied in detail as shown in the Table EBAR.2.


Table EBAR.2: Armitage Creek Manning’s “n” Values Manning’s “n” Values


East Branch DuPage River 0.035 - 0.055 0.055 - 0.090 Armitage Creek 0.024 - 0.035 0.050 - 0.065 Armitage Fork 0.024 - 0.035 0.060 - 0.070 Flood profiles were drawn showing computed water-surface elevations to an accuracy of 0.5 foot for floods of the selected recurrence intervals. Water surface elevations of floods of the selected recurrence intervals were computed through use of the COE HEC-2 step-backwater computer program (USCOE, HEC-2 Water Surface Profiles, Generalized Computer Program, Oct. 1973). Starting elevations for the East Branch DupPge River were developed by the slope-area method; for Armitage Creek, starting elevations were taken at its junctions with the East Branch DuPage River flowlines; and for Armitage Fork, starting elevations were taken at its junctions with the flowlines of the main stem. All elevations are referenced to the National Geodetic Vertical Datum of 1929 (NGVD). The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. 3.3.2.4 Flood Boundaries To reference the flood boundaries for Armitage Creek, see Map Panels: 0208 and 0209. 3.3.2.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.2.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Armitage Ditch (EBAR)EBAR0001 1,452 67 180 4.0 707.8 707.8 707.9 0.11

EBAR0002 2,006 24 83 8.6 710.9 710.9 710.9 0.01

EBAR0003 2,899 54 157 4.6 718.6 718.6 718.6 0.01

EBAR0004 3,501 81 316 2.3 720.8 720.8 720.8 0.01

EBAR0005 3,992 47 169 4.2 722.1 722.1 722.1 0.01

EBAR0006 4,499 127 516 1.4 725.9 725.9 726.0 0.11

EBAR0007 5,423 254 587 1.2 733.2 733.2 733.3 0.11

EBAR0008 5,940 260 979 0.4 733.5 733.5 733.6 0.11

EBAR0009 6,579 290 904 0.5 733.5 733.5 733.6 0.11

EBAR0010 7,455 40 192 2.3 737.6 737.6 737.7 0.11

EBAR0011 8,920 35 100 4.3 741.1 741.1 741.1 0.01

EBAR0012 10,225 12 53 5.7 752.4 752.4 752.5 0.11

EBAR0013 10,620 70 548 0.6 758.6 758.6 758.6 0.01

EBAR0014 11,200 303 1,074 0.3 760.0 760.0 760.1 0.11

EBAR0015 11,690 226 477 0.5 760.1 760.1 760.1 0.01


AND INCORPORATED AREAS ARMITAGE DITCH (EBAR)

In feet above confluence with East Branch DuPage River1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Armitage Fork (EBAR)EBAR0016 1,452 50 8 740.5 740.5 740.5 740.5 0.01

EBAR0017 2,101 191 2 758.2 758.2 758.2 758.2 0.01


AND INCORPORATED AREAS ARMITAGE FORK (EBAR)

In feet above confluence with Armitage Ditch1

TAB

LE5

695

700

705 705

710 710

715 715

720 720

725 725

730 730

735 735

740 740

1200 1700 2200 2700 3200 3700 4200 4700 5200 5700 6200 6700 7200 7700

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ARM

ITAG

E DI

TCH

(EBA

R)

30P

EBAR

0001

EBAR

0002

EBAR

0003

EBAR

0004

EBAR

0005

EBAR

0006

EBAR

0007

EBAR

0008

EBAR

0009

EBAR

0010

LIM

IT O

F DE

TAIL

ED S

TUDY

TREA

TMEN

T PL

ANT

ROAD

WAY

NE A

VENU

E

JILL

COU

RT

LESL

IE L

ANE

ARM

ITAG

E AV

ENUE

GLEN

ELL

YN R

OAD

HIGH

LAND

AVE

NUE

WIN

THRO

P AV

ENUE

CONF

LUEN

CE O

F AR

MIT

AGE

FORK

FULL

ERTO

N AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


720

725

730 730

735 735

740 740

745 745

750 750

755 755

760 760

765 765

7700 8200 8700 9200 9700 10200 10700 11200 11700

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ARM

ITAG

E DI

TCH

(EBA

R)

31P

EBAR

0011

EBAR

0012

EBAR

0013

EBAR

0014

EBAR

0015

ARDM

ORE

AVEN

UE

LINC

OLN

AVEN

UE

POLO

CLU

B RO

AD

PLAC

ID A

VENU

E

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


720

725

730 730

735 735

740 740

745 745

750 750

755 755

760 760

765 765

0 250 500 750 1000 1250 1500 1750 2000 2250 2500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH ARMITAGE DITCH

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ARM

ITAG

E FO

RK (E

BAR)

32P

EBAR

0016

EBAR

0017

CONF

LUEN

CE W

ITH

ARM

ITAG

E DI

TCH

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.3 Army Trail Road Tributary (EBAT)

3.3.3.1 Tributary Description Army Trail Road Tributary is tributary to the East Branch DuPage River. The tributary watershed is found in the headwater region of the East Branch DuPage River watershed. The 282-acre watershed is centered over Army Trail Road in the Villages of Addison and Bloomingdale, flowing west from Route 53 to the East Branch DuPage River. Much of the watershed in the headwaters is impervious due to such highway surfaces as Army Trail Road, Swift Road and I-355. As the watershed nears the confluence with the East Branch DuPage River, the land use changes dramatically to one of high prairie grasses and marshes. In recent years, the land use has changed to a more commercial use throughout the watershed, yet the downstream–most sections remain unaffected. On the northwest side of the intersection of Swift Road and Army Trail Road, evidence of the Army Trail Tributary channel begins. This older residential area dumps storm water runoff into a depression on the north side of Army Trail Road, opposite to Meadow Lane. Conduits pass these waters to the south side of Army Trail Road. The channel takes a westerly track through thick brush and marshes. As the bearing turns more to the south, the channel is more exposed as it goes through a large nursery and agricultural area. The channel turns to the west once more, passing through the Valley View Road culvert and a ComEd Access Road culvert until it reaches the confluence with the East Branch DuPage River. 3.3.3.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharge-frequency data for East Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963).


3.3.3.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the East Branch DuPage River were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for East Branch DuPage River were obtained by field measurement.

The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Since no formal study was completed on Army Trail Tributary, the East Branch DuPage River 100-yr elevation information, determined through the above methods, at the location of the junction between the East Branch DuPage River and Army Trail Road Tributary is used for backwater effects on Army Trail Tributary. In addition to the determined backwater zone information, the unnumbered A-zone boundary was further formed through local studies and the USGS Flood of Record Maps. 3.3.3.4 Flood Boundaries To reference the flood boundaries for Army Trail Road Tributary, see Map Panels: 0206 and 0209.


3.3.4 Crabtree Creek (EBCR)

3.3.4.1 Tributary Description Crabtree Creek is the southern-most watershed tributary to the East Branch DuPage River within DuPage County. With the exception of a very small area, the entirety of Crabtree Creek can be found within the Village of Woodridge. The total watershed area contributing to Crabtree Creek is 983 acres. Crabtree Creek begins on the west side of I-355 and flows in an easterly manner towards the East Branch DuPage River. A branch of Crabtree, joining at midway point of the watershed, proceeds to the northern reaches of the watershed, also ending on the west side of I-355. The modeled section of Crabtree begins upstream of Janes, where it flows east passing underneath such streets as Larchwood Lane, Woodridge Drive, Westview Lane, and Route 53. Crabtree then flows underneath the DuPage County Greene Valley Wastewater Treatment Facility and the Sewage Plant Drive to join the East Branch DuPage River. 3.3.4.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Crabtree Creek. For Crabtree Creek, flood peak discharges were computed using the multiple regression equations stated in “Magnitude and Frequency of Floods in Illinois” (IDOT, 1973). Discharges for the 500-year flood were determined by straight-line extrapolation of a log-probability curve of flood discharges computed for frequencies up to 100 years. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBCR.1

Table EBCR.1: Crabtree Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Crabtree Creek

- within Woodridge


corporate limits 1.45 325 575 740 1,430 East Branch DuPage

River - just d/s of Crabtree Creek 75.3 1,850 2,630 3,080 4,270 Discharges for stream studies by approximate methods were determined from a regional curve that indicated the 100-yr peak discharge, in cubic feet per second (cfs), as a function of acreage stream-bed slope. This curve was determined by solving and plotting solutions to the multiple regression equation adopted by the State of Illinois (IDOT, 1973), for several streams within DuPage County. 3.3.4.3 Hydraulic Analysis

Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Roughness coefficients (Manning’s “n”) for Crabtree Creek were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. The range of “n” values for the streams are found in Table EBCR.2: Table EBCR.2: Crabtree Creek Manning’s “n” Values



Crabtree Creek 0.035 0.065 Water-surface profiles for Crabtree Creek were computed through use of the USACE’s HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Profiles were determined for the 10-, 50-, 100-, and 500-year floods. Starting elevations at the downstream corporate limits for Crabtree Creek were determined from profiles of these streams computed for the FIS of the unincorporated areas of DuPage County (FEMA, 1982).

The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain


unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps.

3.3.4.4 Flood Boundaries To reference the flood boundaries for Crabtree Creek, see Map Panels: 0806, 0809 and 0907. 3.3.4.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.4.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Crabtree Creek (EBCR)EBCR0001 655 42 185 4.0 655.0 655.0 655.0 0.01

EBCR0002 3,655 40 239 3.1 683.3 683.3 683.3 0.01

EBCR0003 5,037 41 103 7.2 698.5 698.5 698.5 0.01

EBCR0004 6,039 94 246 3.0 713.1 713.1 713.1 0.01


AND INCORPORATED AREAS CRABTREE CREEK (EBCR)


TAB

LE 5

620

630

640 640

650 650

660 660

670 670

680 680

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

CRAB

TREE

CRE

EK (E

BCR)

33P

EBCR

0001

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

SEW

AGE

DISP

OSAL

ROA

D

STAT

E HI

GHW

AY 5

3


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


640

650

660 660

670 670

680 680

690 690

700 700

710 710

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

CRAB

TREE

CRE

EK (E

BCR)

34P

EBCR

0002

EBCR

0003

WES

TVIE

W L

ANE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

680

690 690

700 700

710 710

720 720

5200 5400 5600 5800 6000 6200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

CRAB

TREE

CRE

EK (E

BCR)

35P

EBCR

0004

WOO

DRID

GE D

RIVE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.5 East Branch Tributary No. 1 (EBE1)

3.3.5.1 Tributary Description Tributary No. 1 to the East Branch DuPage River is a relatively small tributary with a watershed area of 431 acres. The communities of Addison, Lombard and Unincorporated DuPage County all contribute watershed area to this tributary. The land use of Tributary No. 1 is somewhat divided between impervious areas and vacant prairie. Tributary No. 1 begins its flow one half mile north of North Avenue at Route 53. The tributary proceeds to the west where it runs into I-355. The tributary follows the eastern ditch of I-355 to North Avenue where flow is channeled under I-355. Once flow emerges on the west side of I-355, the channel resumes a westerly course, passes under Swift Road, enters the East Branch Forest Preserve and joins the East Branch DuPage River. 3.3.5.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Tributary No. 1. Discharges for the 10-year, 50-year, and 100-year floods for East Branch Tributary No. 1 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBE1.1.

Table EBE1.1: East Branch Tributary No. 1 Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr East Branch Tributary No. 1

- at mouth 0.44 85 155 210 330 3.3.5.3 Hydraulic Analysis


Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). Roughness coefficients (Manning’s “n”) for East Branch Tributary No. 1 were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Table EBE1.2: East Branch Tributary No. 1 Manning’s “n” Values



E.B. Tributary No.1 0.045 - 0.070 0.045 - 0.080 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.5.4 Flood Boundaries To reference the flood boundaries for East Branch Tributary No. 1, see Map Panels: 0209, 0307, 0503 and 0601. 3.3.5.5 Floodways


No floodway information is available for this tributary. 3.3.5.6 Flood Profiles Please reference attached Flood Profile Sheets


680

685

690 690

695 695

700 700

705 705

710 710

715

720

725

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 1 (E

BE1)

44PEB

E100

01

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

UNNA

MED

ROA

D

SWIF

T RO

AD


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


EAST BRANCH DUPAGE RIVER100-YEAR BACKWATER FROM

*DATA NOT AVAILABLE

690

695

700 700

705 705

710 710

715 715

720 720

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 1 (E

BE1)

45P

EBE1

0002

EBE1

0003

NORT

H AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE


3.3.6.1 Tributary Description East Branch Tributary No. 2 is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The watershed location within the County is shown in Figure 1. The East Branch Tributary No. 2 Watershed covers approximately 1.2 square miles (768 acres). This watershed includes parts of the Villages of Glen Ellyn and Glendale Heights, and areas in unincorporated Milton and Bloomingdale Townships. Tributary No. 2 flows into the main channel of the East Branch of the DuPage River 3,500 feet south of North Avenue (Illinois State Route 64), just upstream of the Great Western Trail.

The mainstem of Tributary No. 2 begins at a detention pond on the north side of James Court serving a subdivision in Glendale Heights north of North Avenue. The tributary then proceeds through a series of closed conduits leading to an outfall located 900 feet south of North Avenue behind the site of a vacant strip mall. The flow continues in a channel through a wooded wetland to just upstream of Main Street. Tributary No. 2 flows from west to east between Main Street and the East Branch of the DuPage River. At Main Street, a small tributary draining from the southwest joins the mainstem of Tributary No. 2.

Between Main Street and Park Boulevard, low flows are carried in a corrugated metal storm sewer, and an overflow channel is provided for high flows. A crossover structure just east of Glen Ellyn Road is designed to assure full flow in the storm sewer before flow enters the overflow channel. Streambank stabilization was completed by DuPage County on the overflow channel in 1994 for the reach between Main Street and Forest Avenue. Between Forest Avenue and Park Boulevard, the overflow passes through a wide grassy area that may have been designed for flood storage. The culverts at both Forest Avenue and Park Boulevard consist of one circular pipe and one arch-shaped corrugated metal pipe (CMP).

Approximately 450 feet downstream of Park Boulevard, the flow is confined in two 400-foot long corrugated metal pipes, which carry the flow under Second Street and Goodrich Avenue. Downstream of the outlets of these pipes, the County has constructed channel improvements and erosion protection for a distance of 400 feet. Just downstream of this channel improvement, there is a 200-foot long, corrugated metal culvert that was installed by the owner of parcel number 05-02-215-013. The fill over the culvert has completely eliminated the channel across most of the parcel. The culvert outlet is approximately 120 feet upstream of Glenrise Avenue. There are three CMP arch culverts at both Glenrise and Eastern Avenues. Both sets of culverts exhibit poor alignment and accumulation


of sediment. A fourth circular pipe at Eastern Avenue is completely blocked by sediment and debris. The area from downstream of Goodrich Avenue to just upstream of Eastern Avenue also has experienced erosion problems. Downstream of Eastern Avenue, portions of the channel banks and floodplain are heavily wooded with areas of both wooded and open wetland. Approximately 500 feet downstream of Eastern Avenue, the Tributary No. 2 channel splits into two distributaries for the remaining 700 feet to the East Branch. The south distributary channel is dry during low flow periods.

Just south of the Great Western Trail, the southwest tributary begins in the area between Pleasant and Prairie Avenues. This area drains through a storm sewer system to a 54-inch culvert under the trail. Then the flow travels through a series of culverts and constructed channels past the Center Ice of DuPage Ice Arena north of Poss Street. From the ice arena, the southwest branch flows due east under Highland Avenue and past the Seventh Day Adventist Church School to Main Street. Storm sewers carry flow north along Main Street to the Tributary No. 2 main channel.

Single-family residential subdivisions are the primary development in the watershed. A vacant strip mall formerly anchored by a Venture store is located along the south side of North Avenue, west of Main Street. A large wetland area behind this strip mall and an area known as Stacey Park are some of the undeveloped areas. The watershed includes about 1 mile of both North Avenue and Glen Ellyn Road/Main Street and smaller segments of St. Charles Road and Geneva Road. Main Street is known as Glen Ellyn Road north of North Avenue.

3.3.6.2 Hydrologic Analysis The DuPage County Department of Development and Environmental Concerns have been working with the Northeastern Illinois Planning Commission (NIPC) to perform the regional hydrologic analysis for various watersheds since early 1980. A continuous hydrologic model, Hydrologic Simulation Program, FORTRAN (HSPF), was used to simulate the hydrologic characteristics of the watershed. HSPF uses a Watershed Data Management (WDM) file for storing input and output data. The current WDM file contains detailed precipitation data, other meteorologic data, recorded stream flow data, and simulated runoff and streamflow throughout DuPage County. Data is available back to 1948. The precipitation, meteorologic, and recorded streamflow data, along with land cover data are used to develop and calibrate the HSPF model to produce the simulated runoff for six land cover types. The land cover areas for each of the six land covers are generated by County's Geographic Information Systems (GIS) for each watershed. The six land cover types are impervious: flat, medium, and steep grass; forestland; and


agricultural/cropland. The procedures used for hydrologic analysis are discussed in Application Guide for Hydrologic Modeling in DuPage County using Hydrologic Simulation Program – Fortran (HSPF), (Price, 1996). HSPF simulates continuous hourly runoff from continuous precipitation and meteorologic data. Both surface and subsurface runoff are simulated. Thus, both stormflow and baseflow are simulated.

Hydrologic modeling for the entire East Branch DuPage River watershed including Tributary No. 2 is documented in Hydraulic Evaluation of HSPF Model for East Branch DuPage River Watershed (Price and Chang, 2001). This document describes the development and calibration of an HSPF model used to represent runoff from land covers throughout the East Branch watershed. The calibrated HSPF model generates unit runoff in inches per hour for six typical land covers. The land covers were developed for soil and vegetative conditions typically found in DuPage County. These land covers represent impervious area, flat, medium and steep sloped grassed areas, forest and agricultural land. Land segments in each tributary subbasin are assigned to one of these land covers within the hydraulic model. Within the hydraulic model, the area is associated with the appropriate HSPF runoff.

Hydrologic Calibration HSPF was regionally calibrated to five streamflow gages in the three primary watersheds in DuPage County (Salt Creek, East Branch of the DuPage River, and West Branch of the DuPage River) and then verified using a separate period of record and additional streamflow gates (ten total gages). The model was later applied in two smaller watersheds at the edge of the County, Sawmill Creek and Springbrook #2 to the DuPage River. The calibration and verification are described in "Hydrologic Calibration of HSPF Model for DuPage County" (NIPC, 1994) and in "Meteorologic Database Extension and Hydrologic Calibration and Hydraulic Evaluation of HSPF Model for Sawmill Creek Watershed" (NIPC, 1996). During the regional calibration and verification of the three primary watersheds and application in Sawmill Creek, it was found that a single set of HSPF model parameters (for each of the six land cover types) was applicable throughout each of the watersheds.

During calibration of the HSPF model, only unrouted runoff volumes were compared to annual, monthly, and event streamflow volumes. Thus, the model was not calibrated in terms of matching peak flows or timing of runoff within events. That portion of the hydrologic calibration occurs during the hydraulic modeling of specific watersheds and is termed "hydraulic evaluation". After hydraulic routing, the runoff through the stream network system, a final adjustment of HSPF model parameters can occur to produce appropriate timing of runoff within events.


Relationship between Hydrologic Simulation and Hydraulic Simulation After the HSPF model is calibrated, the simulated runoff is routed through the stream network using a separate hydraulic model called FEQ. The simulated runoff stored in the WDM (HSPF) is with a format that is incompatible with the FEQ. Thus, a utility program called "WDMUTL" is used to export runoff from the WDM into a time series file (TSF) to be used in the FEQ model. The TSF contains runoff for each of the six land cover types and for each precipitation gage used to generate the runoff.

A number of TSFs are created for various purposes. Most of the files are used in hydraulic calibration and are created for specific portions of the County or for specific watersheds. This type of TSFs use a detail network of long-term or short-term precipitation gages to better define the temporal and spatial distribution of the calibration storm. The other type of TSFs are created for Countywide use in flood plain studies and alternative analysis. They are TSFLONG and TSFBIG. TSFLONG is based on precipitation data from the O'Hare and Wheaton long-term gages from water years 1949 through 1993. Instead of simulating the entire 45 years of record, DuPage County selected 115 discrete storms, which generated significant runoff volumes. The results from TSFLONG are used to perform frequency analysis. TSFBIG contains runoff based on very large precipitation events that have occurred in the Midwest. These events are used to assess performance of the stream system and hydraulic features under very extreme conditions.

3.3.6.3 Hydraulic Analysis Hydraulic analysis was conducted using the continuous simulation hydraulic analysis software FEQ. Using FEQ, a detailed model of the Tributary No. 2 drainage network was developed. The model simulates flow storage in detention ponds, natural storage areas and floodplains. It also calculates the depth and discharge of flow through open channels, storm sewers and overflow paths.

Overview of FEQ Software Program FEQ, or Full Equations Model, was developed by Dr. Delbert Franz of Linsley, Kraeger Associates, Ltd. (Franz, 2001) FEQ is used to simulate flow in a stream system by solving numerically the equations for unsteady flow in open channels and through control structures. The program separates the flows into three broad classes: stream reaches, dummy reaches, and level-pool reservoirs. These three parts are then combined using different control structures, such as junctions, bridges, culverts, dams, waterfalls, spillways, weirs, side weirs, pumps, and others. FEQ determines the flow and depth throughout the stream system given initial and boundary conditions. FEQ can also be applied in the simulation of a wide-range of stream configurations, such as loops, lateral-inflow


conditions, and special features. The boundary conditions can be values such as the water-surface stage, discharge, or the stage-discharge relationship at a node. Wind stress may also be included in the analysis, as well as the effects of lateral inflows, when given local runoff intensity data.

FEQ model input consists of the following elements:

83. Run Control – specifies the simulation length and model execution options.

84. Branch Description – defines channel stationing, flow line elevations and cross-section locations.

85. Tributary Area – defines drainage area and land cover proportions draining to each branch and reservoir represented in the model.

86. Network Control Input – describes how the system is connected together and specifies the function tables used to represent hydraulic structures.

87. Operation of Control Structures – there are no operable structures in the Tributary No. 2 drainage network.

88. Input Files – files containing time series of external flow inputs to the system.

89. Output Files – files written by FEQ to be used as flow input to another FEQ model.

90. Special Output – text file output of flow and stage at each time step for a set of specific modeled locations.

91. Function Tables – all cross-section and hydraulic structure information is stored in tables, which must be read into the model.

92. Initial Condition – provides information FEQ needs to determine an initial network solution that can be used as a model boundary condition.

FEQ Model of Tributary No. 2 Detailed FEQ modeling was developed for 6,300 feet of the main channel of Tributary No. 2 and for 3,470 feet of its southwest tributary. Modeling of the mainstem continues an additional 1,800 feet through storm sewers north to the James Court detention pond in Glendale Heights.


The model consists of 26 branches representing reaches of open channel and storm sewers in the Tributary No. 2 drainage system, and 12 branches in the portion of the model taken from the FEQ model of the East Branch main channel. Function tables were used to represent additional hydraulic features such as culverts, expansions, contractions, inlet structures, and weirs. Four linear reservoirs and two detention ponds are represented in the model. Five additional surface ponding areas are also modeled as level pool reservoirs. The wetland area west of Main Street is represented in FEQ as a channel-routed reservoir.

The hydraulic characteristics of the stream system were obtained from field surveys performed in 1987 and 1995. Additional data was collected from DuPage County aerial photo and topographic maps and from IDOT plans for North Avenue. Hydrologic inputs and East Branch main channel data were provided by DuPage DEC. Watershed subbasin delineations were conducted on DuPage DEC 2-foot contour interval topographic maps and verified during field inspection. The watershed boundaries for Tributary No. 2 were previously established by the DEC and were verified to be correct. Field survey data collected includes cross-sections of the stream and floodplain, hydraulic structures such as bridges, culverts, dams, weirs, and other hydraulic controls.

Existing (1990) as well as future conditions (ultimate development) land cover data for the Tributary No. 2 watershed were obtained from DuPage County’s GIS system. The future conditions land use was used for economic and project analysis and for floodplain mapping. Existing conditions land use was used for hydraulic calibration. The land cover data for the Tributary No. 2 input to the FEQ program represents the tributary area characteristics of the Tributary No. 2 Watershed. This data is combined with the individual land cover runoff series obtained from the HSPF simulation. This process is further described in the "Hydrologic and Hydraulic Methods Report" (DuPage DEC, 1994), and the "East Branch Hydraulic Evaluation" (Price and Chang, 2001). Approximately 28 percent of the watershed was found to have impervious land cover under current land use conditions. Impervious area is estimated to increase to 36 percent under future land use conditions.

Streams Modeled The East Branch Tributary No. 2 model contains detailed modeling of the mainstem contains 6334 feet of open channel up to an outfall which is located in the former site of the Venture strip mall. There is also 1769 feet of storm sewer between the James Court detention pond and the outfall. The second stream is the Southwest Tributary. This tributary has 400 feet of parallel storm sewers running along Main Street. The Southwest Tributary has an additional 700 feet of open channel extending up to the parking lot on the north side of Poss Street. The Southwest Tributary also


receives water from ponding areas south of the Great Western Trail. The total lengths and stationing of the storm sewers and detention areas were determined using the DuPage GIS system.

Cross-Section Data All model cross-sections must be portrayed in the DuPage County GIS. An ArcInfo script program, known as XDI was used to input and manipulate model cross-sections. The following functions were performed using XDI:

93. Entering the survey data into the County GIS

94. Extension of cross-sections that do not cover the full extent of the flood plain

95. Review and editing of cross-sections to screen out inappropriate survey points

96. Fabrication of cross-sections at additional locations needed for modeling

XDI generates text output in FEQUTL format for processing using the FEQX command. XDI also calculates the stream station of each cross-section.

The channel cross-sections were surveyed in 1987 and 1994 by Donohue and Associates. Twenty-six channel and floodplain cross-sections were surveyed. As they were surveyed, State Plane Coordinates were determined for each surveyed elevation location. Where possible, all of the surveyed cross-section points were used in the analysis. If any extra information was needed, such as horizontal extensions, the County’s XDI software and digital topography were used as needed.

In addition to the surveyed cross-sections, there were also fabricated cross-sections used in the analysis. The fabricated cross-sections were created for various reasons. Some of the surveyed cross-sections were surveyed with no state plane coordinates. For this situation, the approximate location is determined and the State Plane Coordinates were assumed. This data was then used along with the surveyed elevations. There were also fabricated sections generated from existing surveyed sections. Overland flow sections were fabricated sections was well. All of the fabricated sections were extended using XDI.

Table EBE2.1 lists the cross-section ID, the table number, the low point (flow line elevation) and station.

Table EBE2.1. Surveyed Channel Cross Sections


Cross Section Description FEQ Table

Number 0 Janus Wetland 100 1 Janus Wetland 101 2 D/S of Eastern Ave 102 3 U/S of Eastern Ave 103 4 Between Eastern Ave and Glenrise Ave 104 5 D/S of Glenrise Ave 105 6 U/S of Glenrise Ave 106 7 Between Glenrise Ave and Goodrich Ave 107 8 Between Glenrise Ave and Goodrich Ave 108 9 Between Goodrich Ave and Park St 109 10 D/S of Park St 110 11 U/S of Park St 111 12 Between Park St and Forest Ave 112 13 D/S of Forest Ave 113 14 U/S of Forest Ave 114 15 D/S of Main St (Glen Ellyn Rd) 115 16 U/S of Main St (Glen Ellyn Rd) 116 17 Through wetland west of Main St 117 18 Through wetland west of Main St 118 19 Through wetland west of Main St 119 20 U/S of Glen Ellyn Rd 120 21 Between Highland Ave and Main St 121 22 20' D/S of Highland Ave structure 122 23 Constructed channel around Ice Areana 123 24 U/S 3.5 ft drop 124 25 U/S of Great Western Trail bike path 125

Another group of cross-sections are classified as closed conduits. Closed conduits of significant length were modeled as branches. A list of the closed conduits represented in the Trib 2 FEQ model is in Table EBE2.2.

Table EBE2.2. Closed Conduits

Description Location Table

Number FEQ Branch65 by 40 CMP Arch Main St to Park Ave and Private Pipe 665 9, 8, 4

Twin 87 by 63 CMP Arch Under 2nd St and Goodrich Ave 687 6

48 by 84 RCP Elliptical Under vacant strip mall 684 12

18" Circular RCP Under Main St 618 14

24" Circular RCP Under Main St 624 26

36" Circular RCP Under Poss St, Main St, and Ice Arena 636 18, 22, 24

Twin 34 by 18 CMP Culvert Under Highland Ave 634 21


42" Circular RCP North of North Ave 642 13

78 by 54" CMP Arch Main St culvert 678 100

Manning n-values were assigned to the horizontal segments of each cross-section. Each n-value was determined from the characteristics of the channel cross-section, using values determined from Chow, 1959. The channel n-values as well as the overbank n-values were determined.

Tributary Area East Branch Tributary No. 2 was delineated into 35 subbasins. These subbasins generally correspond to the areas draining to each branch and reservoir node represented in the FEQ model. Several “extra” subbasins were created for possible future use, while some branches, such as short closed conduits were not assigned any tributary area. The areas from the 35 subbasins are allocated to 29 branches and nodes. One subbasin (11B) is not assigned because it does not appear to discharge to the Tributary No. 2 stream network. A total of 1.176 square miles of area was assigned to FEQ branches and reservoirs.

The DuPage County GIS was used to determine land cover areas within each subbasin. There are GIS coverages available for calculating both current and future land cover.

Hydraulic Structures Nineteen major hydraulic structures were modeled explicitly in the Tributary 2 FEQ model not counting the storage area outlets discussed in Section 3.2.2.6. These structures are mostly road crossing culverts and storm sewers but there are also a few channel transitions and unusual inlet structures. These structures are listed in Table EBE2.3 along with the FEQ modeling approach employed for each structure. FEQ provides many tools for use in representing hydraulic structures. Some typical approaches are described below.

Roadway culverts are represented using a combination of FEQUTL commands. One or more CULVERT commands are used to compute tables for flows through the culvert barrels. The EMBANKQ command is used to calculate flow over the roadway within the channel banks and a CHANRAT table is used for flow over the road that occurs in each overbank. This approach was used to model five Tributary 2 structures.

Long culverts and storm sewers are represented in FEQ as regular branches. This approach has the advantages of applying the full unsteady flow solution to the structure and assures that stored flow within the structure is accounted for. The EXPCON command in FEQUTL is used to calculate entrance and exit losses for the transitions between open


channel and storm sewers. Ten sewers and culverts are represented as branches in the Tributary No. 2 model.

Unusual structures such as slope box inlets are typically modeled using a combination of FEQUTL commands and manual modifications to the computed table. There are four inlet structures that employ manually adjusted 2-D tables in the Tributary No. 2 FEQ model.

There are two major channel transitions in the Tributary 2 watershed where there are sudden expansions in channel dimensions. These transitions are modeled using the EXPCON command.

Table EBE2.3. Hydraulic Structures Stream Structure

Number Structure Modeling Approach

Confluence with East Branch EXPCON S-1 Eastern Ave CULVERT, EMBANKQ, CHANRAT S-2 Glenrise Ave CULVERT, EMBANKQ, CHANRAT Private Pipe FEQ Branch, EXPCON S-3 Culvert under Second Street and

Goodrich FEQ Branch, EXPCON

S-4 Park Blvd CULVERT, EMBANKQ, CHANRAT S-5 Forest Ave CULVERT, EMBANKQ, CHANRAT Storm Sewer from Main St. to

Park St. FEQ Branch, EXPCON

S-6 Box Inlet D/S of Main St Fabricated 2D Table S-6 Main St. Culvert FEQ Branch, EXPCON

Main Channel

S-7 Storm Sewer under Venture FEQ Branch, EXPCON Storm sewers under Main St. FEQ Branch, EXPCON S-9 Inlet structure on W. side of Main Fabricated 2D Tables S-12 Storm Sewer under Ice Arena FEQ Branch, EXPCON S-11 Culvert under Highland FEQ Branch, EXPCON Sudden Drops in Channel Invert

U/S of Ice Arena EXPCON

S-13 Storm Sewer under parking lot FEQ Branch, EXPCON S-16 Great Western Trail CULVERT Pleasant-Prairie Storm Sewers FEQ Branch

SW Tributary

Pleasant-Prairie Inlets Fabricated 2D Tables

Storage Areas and Detention Basins Storage areas and detention basins typically are modeled in FEQ as level-pool reservoirs although it is also possible to model in-line storage as a branch. Outlet flows can be modeled either as simple rating curves or as 2-dimensional ratings that account for submergence. The Tributary No. 2 FEQ model includes eleven level pool reservoirs. These included four


linear reservoirs, two detention ponds, and five surface ponding areas as listed in Table EBE2.4.

Linear reservoirs are a modeling device used to simulate the effect of diffuse storage and overland flow on the runoff from a subbasin. No real storage pond exists in the subbasin, (or if one does, it is not modeled explicitly). The linear reservoir is used to replicate the attenuation of the runoff hydrograph that is observed in large subbasins with significant overland flow. Four remote subbasins are modeled using linear reservoirs.

Table EBE2.4. Level Pool Reservoirs in the Tributary No. 2 Model Description Type Model Node Outlet

Subbasin F3 Linear F3 1-D Linear Relation Wetland Northeast of North Avenue and Glen Ellyn Road

Ponding Area F5 EMBANKQ

James Court Detention Detention Pond F7 CULVERT Subbasin F9 Linear F9 1-D Linear Relation Subbasin F19N and F19S Linear F19 1-D Linear Relation Ponding between Poss Street and the Great Western Trail

Ponding Area F15 EXPCON

Ponding U/S of Great Western Trail

Ponding Area F17 CULVERT

Ponding Area on Prairie Avenue

Ponding Area F53 ORIFICE and EMBANKQ

Ponding Area on Pleasant Avenue

Ponding Area F55 ORIFICE and EMBANKQ

Denby Woods Pond Detention Pond F57 ORIFICE Subbasin 17C and 17D Linear F59 1-D Linear Relation

Seven additional ponding areas are modeled as real reservoirs. For these, storage-area-elevation data was derived using DuPage DEC topographic maps and outlet conditions were modeled using appropriate FEQUTL commands.

3.3.6.4 Flood Boundaries To reference the flood boundaries for East Branch Tributary No. 2, see Map Panels: 0208, 0209, 0502 and 0503. 3.3.6.5 Floodways Conveyance floodways were determined for each modeled open channel cross section for East Branch Tributary No. 2 using the FEQUTL FLOODWAY command using the PVSTATS computer program. The equal conveyance option was employed in the command. This command


calculates cross-section encroachments that result in equal losses of conveyance from each side of the floodplain. Encroachments are increased until either the water-surface elevation rises 0.1 foot or the total conveyance loss reaches 10 percent. Please reference attached Floodway Data Tables for further information. 3.3.6.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch Tributary No. 2 (EBE2)

EBE20100 494 476 2,255 2.3 699.0 699.0 699.1 0.11

EBE20101 1,073 323 518 2.8 699.4 699.4 699.5 0.11

EBE20102 1,501 220 321 7.5 702.1 702.1 702.2 0.11

EBE20103 1,564 548 913 2.1 705.1 705.1 705.2 0.11

EBE20104 1,953 110 279 3.4 705.7 705.7 705.8 0.11

EBE20105 2,315 73 201 11.4 707.4 707.4 707.5 0.11

EBE20106 2,379 144 550 1.8 709.7 709.7 709.8 0.11

EBE20107 2,834 126 410 2.5 710.2 710.2 710.3 0.11

EBE20108 3,077 89 326 2.8 710.6 710.6 710.7 0.11

EBE20109 3,677 96 404 1.8 714.6 714.6 714.7 0.11

EBE20110 3,925 54 245 12.8 714.7 714.7 714.8 0.11

EBE20111 4,024 154 717 0.9 716.9 716.9 717.0 0.11

EBE20112 4,207 144 524 1.1 716.9 716.9 717.0 0.11

EBE20113 4,376 97 294 16.7 717.0 717.0 717.1 0.11

EBE20114 4,469 135 543 2.8 719.9 719.9 720.0 0.11

EBE20115 4,851 30 59 5.6 720.4 720.4 720.5 0.11

EBE20116 4,998 93 220 1.8 722.6 722.6 722.7 0.11


AND INCORPORATED AREAS EAST BRANCH TRIBUTARY NO. 2 (EBE2)

In feet above Confluence with East Branch DuPage River1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch Tributary No. 2 (EBE2)

EBE20117 5,331 128 260 1.0 722.9 722.9 723.0 0.11

EBE20118 5,576 151 272 1.1 723.0 723.0 723.1 0.11

EBE20119 6,049 194 344 1.1 723.2 723.2 723.3 0.11


AND INCORPORATED AREAS EAST BRANCH TRIBUTARY NO. 2 (EBE2)

In feet above Confluence with East Branch DuPage River1

TAB

LE 5

685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

730 730

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 2 (E

BE2)

46P

EBE2

0100

EBE2

0101

EBE2

0102

EBE2

0103

EBE2

0104

EBE2

0105

EBE2

0106

EBE2

0107

EBE2

0108

EBE2

0109

EBE2

0110

EBE2

0111

EBE2

0112

EBE2

0113

EBE2

0114

EBE2

0115

EBE2

0116

EBE2

0117

EBE2

0118

EBE2

0119

EAST

ERN

AVEN

UE

GLEN

RISE

AVE

NUE

PRIV

ATE

CULV

ERT

PRIV

ATE

CULV

ERT

PARK

BOU

LEVA

RD

MAI

N ST

REET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERTS

CULVERT

CULVERTS

CULVERTS

FORE

ST A

VENU

E

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER


3.3.7.1 Tributary Description The East Branch Tributary No. 3 is a 312-acre watershed that lies primarily in the Village of Lombard. The watershed is residential in nature, with such road features as I-355 near the mouth of the tributary and Finley Road bisecting the watershed from north to south. East Branch Tributary No. 3 begins at Four Seasons Park in Lombard, on the east side of Finley Road approximately one half mile south of Roosevelt Road. The tributary curves to the north, then west, passing underneath Finley Road and Aspen Drive. The tributary proceeds west behind several dead-end streets and housing complexes until it crosses Aspen Road again. The reach passes underneath S. Lloyd Avenue, enters a marshy area on the east side of I-355, proceeds underneath I-355 and immediately joins the East Branch DuPage River on the west side of the highway. 3.3.7.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharge-frequency data for East Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). 3.3.7.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the East Branch DuPage River were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain


management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for East Branch DuPage River were obtained by field measurement.

The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Since no formal study was completed on East Branch Tributary No. 3, the East Branch DuPage River 100-yr elevation information, determined through the above methods, at the location of the junction between the East Branch DuPage River and the East Branch Tributary No. 3 is used for backwater effects on East Branch Tributary No. 3. In addition to the determined backwater zone information, the unnumbered A-zone boundary was further formed through local studies and the USGS Flood of Record Maps. 3.3.7.4 Flood Boundaries To reference the flood boundaries for East Branch Tributary No. 3, see Map Panels: 0506 and 0604 3.3.7.5 Floodways No floodway information is available. 3.3.7.6 Flood Profiles No flood profile information is available.



3.3.8.1 Tributary Description East Branch Tributary No. 6 (previously known as St. Procopius Creek) is a relatively large watershed consisting of approximately 1183 acres. This watershed flowing primarily from west to east is within the communities of Lisle, Naperville and Unincorporated DuPage County. The overall land use of the watershed is divided into three parts: institutional / commercial, medium-high density residential and low density residential. Both the institutional grounds (Benedictine University) and the low density residential are within Unincorporated DuPage County and Woodridge, where the high density residential is primarily found in the community of Lisle. Three branches of East Branch Tributary No. 6 exist. This first, northernmost branch begins at Benedictine University and flows the to southeast. The branch passes underneath College Road and Millridge Lane, until it confluences with the second branch at Seven Bridges Golf Course. The second branch begins in Naperville, where it quickly passes into Lisle – both areas being of higher density residential. Much of this second branch appears to be submerged in pipe, but emerges from the pipe upstream of College Road, just south of Abbeywood Drive. The second branch passes east underneath College Road, proceeds behind several townhouses, and passes underneath Golf View Drive. This second branch joins the first branch on the northwestern edge of the Seven Bridges Golf Course. The joined branch continues to the south, passing under Greene Road and Greene Trails Drive through higher density residential areas in the Village of Woodridge. On the south side of Greene Trails Drive, the second branch encounters the third, and final, East Branch Tributary No. 6 branch. The third branch begins in low-density residential areas in the southern part of the watershed. The branch, starting in Eggerman Woods Forest Preserve (at the NE corner of Hobson and College Roads) proceeds on a Northeast bearing through upscale residential areas, passing underneath Donwood Drive West and Donwood Drive East. Traveling east, the third branch passes through Donwood Trails Drive and Oak Trails Drive. On the east side of Oak Trails Drive, the third branch converges with branch two. The joined tributary continues to the east where it passes underneath Greene Trails Drive and Greene Road to join the East Branch DuPage River at the Seven Bridges Golf Course. 3.3.8.2 Hydrologic Analysis


Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharges for East Branch Tributary No. 6 (St. Procopius Creek) were computed by using the square root of the drainage areas ratio applied to the results for Lacey Creek. Lacey Creek is a local area tributary of the East Branch DuPage River considered to have similar drainage characteristics to East Branch Tributary No. 6. Discharges for the 500-yr floods of all stream were determined by linear extrapolation of a log-probability graph plotted for calculated peak discharges. Peak discharges for the 10-, 50-, 100-, and 500-year floods are shown in Table EBE6.1. Table EBE6.1: East Branch Tributary No. 6 (St. Procopius Creek) Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr East Branch Tributary No. 6

- approx. 600 feet d/s of Mill Bridge Lane 0.68 170 265 320 440 3.3.8.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The 100-year flood stage for streams studied by approximate methods was determined by solving Manning’s equation for depth of flow in the channel.


These streams were field surveyed to obtain typical stream cross sections, average stream channel slope, and Manning’s “n” values. Roughness coefficients (Manning’s “n”) for East Branch Tributary No. 6 were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Please see table EBE6.2 for further information. Table EBE6.2: East Branch Tributary No.6 Manning’s “n” Values



East Branch Tributary No. 6 0.035 - 0.040 0.060 - 0.080 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.8.4 Flood Boundaries To reference the flood boundaries for East Branch Tributary No. 6, see Map Panels: 0804, 0805 and 0808. 3.3.8.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.8.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


St. Procopius Creek (EBE6)

EBE60001 8,498 21 62 5.2 704.9 704.9 704.9 0.01

EBE60002 8,817 40 144 2.2 708.6 708.6 708.6 0.01

EBE60003 9,724 104 224 1.4 714.4 714.4 714.5 0.11

EBE60004 10,270 138 70 4.6 717.8 717.8 717.8 0.01


AND INCORPORATED AREAS ST. PROCOPIUS CREEK (EBE6)


TAB

LE 5

670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

715 715

6800 7000 7200 7400 7600 7800 8000 8200 8400 8600 8800 9000 9200 9400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. P

ROCO

PIUS

CRE

EK (E

BE6)

54PEB

E600

01

EBE6

0002

LIM

IT O

F DE

TAIL

ED S

TUDY

MIL

L BR

IDGE

LAN

E


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

9400 9600 9800 10000 10200 10400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. P

ROCO

PIUS

CRE

EK (E

BE6)

55P

EBE6

0003

EBE6

0004

PRIV

ATE

ROAD

COLL

EGE

ROAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50- AND 500-YEAR FLOOD PROFILES ARE TOO CLOSE TO BE SHOWN SEPARATELY


3.3.9.1 Tributary Description East Branch Tributary No. 7 is a 533 acre tributary watershed to the East Branch DuPage River, found in the south-central section of DuPage County. Though containing some watershed area in the City of Naperville, East Branch Tributary No. 7 is almost entirely unincorporated. This area has undergone much recent development in the form of single and multi-family dwellings. Two branches make up the stream length of East Branch Tributary No. 7. The northern, or first branch starts west of Brenwood Drive and south of Hobson Road. The branch flows directly east, passing under Brenwood Drive. The branch turns to the south and follows the backyard lot lines of a residential subdivision, eventually turning to the east encountering the second branch. The second branch of the East Branch Tributary No. 7 begins on the west side of Palomino Road and north of 75th Street. The second branch flows to the east passing beneath Palomino Road. The branch continues to the northeast, following the back lot lines of residential subdivisions until it eventually joins the first branch. The joined branch continues directly east, passes under Greene Road and confluences with the East Branch DuPage River in the Green Valley Forest Preserve. 3.3.9.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharges for the 10-year, 50-year, and 100-year floods for East Branch Tributary No. 7 studied by the limited detail method were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBE7.1.


Table EBE7.1: East Branch Tributary No. 7 Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr East Branch Tributary No. 7

- at mouth 0.71 180 330 425 650 3.3.9.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles. The water-surface elevations for the East Branch Tributary No. 7 studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973. Roughness coefficients (Manning’s “n”) for East Branch Tributary No. 7 were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Table EBE7.2: East Branch Tributary No. 7 Manning’s “n” Values




East Branch Tributary No. 7 0.055 - 0.080 0.080 - 0.100 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. The 100-year flood stage for streams studied by approximate methods was determined by solving Manning’s equation for depth of flow in the channel. These streams were inspected in the field to obtain stream cross-sections, and measurements at bridges and culverts. 3.3.9.4 Flood Boundaries To reference the flood boundaries for East Branch Tributary No. 7, see Map Panels: 0805, 0808 and 0809. 3.3.9.5 Floodways No floodway information is available for this tributary. 3.3.9.6 Flood Profiles Please reference attached Flood Profile Sheets


620

630

640 640

650 650

660 660

670 670

680 680

690 690

700 700

0 400 800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 7 (E

BE7)

56P

EBE7

0001

EBE7

0002

EBE7

0003

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

GREE

NE R

OAD

DRIV

EWAY

TO

DERB

Y DR

IVE

FOOT

BRID

GE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROMEAST BRANCH DUPAGE RIVER

* DATA NOT AVAILABLE

660

670

680 680

690 690

700 700

710 710

720 720

730 730

5200 5600 6000 6400 6800 7200 7600 8000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 7 (E

BE7)

57P

EBE7

0004

EBE7

0005

EBE7

0006

EBE7

0007

PRIV

ATE

ROAD

TO

75TH

STR

EET

FOOT

BRID

GE

MUR

RAY

DRIV

E

PALO

MIN

O DR

IVE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD50-YEAR FLOOD*10-YEAR FLOOD

STREAM BED



3.3.10 Glen Crest Creek (EBGL)

3.3.10.1 Tributary Description Glen Crest Creek (previously known as East Branch Tributary No. 4) is a 1739-acre watershed that is tributary to the East Branch DuPage River. Primarily draining the Village of Glen Ellyn, Glen Crest Creek has contributing watershed area from the Villages of Wheaton and Lombard, and Unincorporated DuPage County. The bulk of the land use is suburban residential, with a rather large recreational area / golf course centered in the middle of the watershed. Much of the watershed, especially in the headwaters, has been placed in conduit. There are two branches of Glen Crest Creek that deserve attention. The first is a short branch that starts at the reservoir created at Glen Ellyn’s Panfish Park, located a few hundred feet to the south of Roosevelt Road and bounded on the east and west by Route 53 and Park Boulevard respectively. Storm waters enter the site from the northeastern section of the watershed, and exit through a conduit to the southwest. The conduit opens up at The Links Golf Course where branch one encounters branch two. Branch two begins in the northern section of the Links Golf Course. Branch two drains all waters from the northcentral and northwestern parts of the watershed. After joining branch one, branch two enters another conduit system that proceeds to the southeast. The channel opens up upon entering the Willowbrook Forest Preserve Wildlife Haven, and remains in an open state until the confluence with the East Branch DuPage River. The branch takes a northeasterly course and passes under Sheffield Road, 22nd Street and Route 53. The bearing changes to the southeast where the branch continues under Bemis Road and Glen Crest Drive before encountering the East Branch DuPage River. 3.3.10.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Glen Crest Creek. Discharges for the 10-year, 50-year, and 100-year floods for Glen Crest Creek studied in detail and for the 10-year and 100-year events for streams studied by the limited detail method were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.


Hydrologic computations for the Village of Glen Ellyn Links storm retention system, as well as other areas in the village which experience shallow flooding, were based on the SCS Technical Release No. 55 (U.S. Department of Agriculture, 1975). The drainage basin of the Village Links system was first subdivided into those areas that drain directly into the golf course ponds, and those that first drain into other ponds and eventually discharge into the golf course ponds through storm sewers. For all areas, storage volumes and release rates applicable to a 100-year flood were then determined. The discharge rate available to direct runoff to the golf course was reduced to account for release rates of upstream ponding areas and storm sewers. The final required detention volume and corresponding 100-year flood elevation for the golf course was then determined. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBGL.1.

Table EBGL.1: Glen Crest Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Glen Crest Creek

- at Leask Lane 4.34 455 730 870 1,200 - at mouth 2.60 370 485 550 750

3.3.10.3 Hydraulic Analysis

Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface profiles of Glen Crest Creek were computed through use of the USACE’s HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Profiles were determined for the 10-, 50-, 100-, and 500-year floods.


Starting elevations at the downstream corporate limits for Glen Crest Creek were determined from profiles of these streams computed for the FIS of the unincorporated areas of DuPage County (FEMA, 1982). 100-year flood elevations along the Village Links storm water retention system were computed from discharge-storage relationships developed for each drainage sub-area. Storm sewer head losses were calculated from standard equations for closed pipe and orifice flows. The 100-year starting water-surface elevation at the stream east of Park Boulevard into which this retention system empties was determined from a slope-area analysis. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. Roughness coefficients (Manning’s “n”) for Glen Crest Creek were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Table EBGL.2: Glen Crest Creek Manning’s “n” Values



Glen Crest Creek 0.065 - 0.085 0.055 - 0.070

3.3.10.4 Flood Boundaries To reference the flood boundaries for Glen Crest Creek, see Map Panels: 0505, 0506, 0508 and 0509. 3.3.10.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.10.6 Flood Profiles


Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch DuPage River Tributary No. 4 (EBGL)

EBGL0001 557 28 94 5.9 684.5 684.5 684.5 0.01

EBGL0002 2,362 93 267 2.1 700.4 700.4 700.5 0.11

EBGL0003 3,293 125 367 1.3 709.9 709.9 709.9 0.01

EBGL0004 4,398 58 181 2.7 715.9 715.9 715.9 0.01

EBGL0005 4,684 110 327 1.5 728.2 728.2 728.2 0.01 2

EBGL0006 5,712 82 178 2.8 729.9 729.9 729.9 0.01



EAST BRANCH TRIBUTARY NO. 4 (EBGL) [GLEN CREST CREEK]

In feet above confluence with East Branch DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

670

675

680 680

685 685

690 690

695 695

700 700

705 705

0 500 1000 1500 2000 2500 3000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 4 (E

BGL)

49P

EBGL

0001

EBGL

0002

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

SUNN

YBRO

OK R

OAD

GLEN

CRE

ST D

RIVE

BEM

IS R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM EAST BRANCH DUPAGE RIVER

695

700

705 705

710 710

715 715

720 720

725 725

730 730

735 735

740 740

3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH EAST BRANCH DU PAGE RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 4 (E

BGL)

50P

EBGL

0003

EBGL

0004

EBGL

0005

EBGL

0006

STAT

E RO

UTE

53(B

RYAN

T AV

ENUE

)

FOOT

BRID

GE

22ND

STR

EET

SHEF

FIEL

D RO

AD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

3.3.11 Glen Park (EBGP)

3.3.11.1 Tributary Description Glen Park Tributary is a 455-acre tributary to the East Branch DuPage River. This rather small tributary has contributing watershed area from the Village of Lombard, the Village of Downers Grove and Unincorporated DuPage County. Glen Park begins on the north side of Butterfield Road (Route 56) in the Village of Downers Grove, just east of I-355. The channel passes west underneath I-355, Glen Park Road, Hampton Road and Valley Road until confluencing with the East Branch DuPage River. 3.3.11.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharge-frequency data for East Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). 3.3.11.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the East Branch DuPage River were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for East Branch DuPage River were obtained by field measurement.


The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Since no formal study was completed on Glen Park Tributary, the East Branch DuPage River 100-yr elevation information, determined through the above methods, at the location of the junction between the East Branch DuPage River and Glen Park Road Tributary is used for backwater effects on Glen Park Tributary. In addition to the determined backwater zone information, the unnumbered A-zone boundary was further formed through local studies and the USGS Flood of Record Maps. 3.3.11.4 Flood Boundaries To reference the flood boundaries for Glen Park Tributary, see Map Panels: 0509 and 0607. 3.3.11.5 Floodways No floodway information is available. 3.3.11.6 Flood Profiles No flood profile information is available.


3.3.12 Lacey Creek (EBLA)

3.3.12.1 Tributary Description Lacey Creek is a 2955-acre watershed tributary to the East Branch DuPage River. Communities contributing watershed area to Lacey Creek are primarily Downers Grove and Unincorporated DuPage County, but a very small portion of Oak Brook contributes on the very eastern edge of the watershed. The land use for Lacey Creek is extremely diverse. The northeastern and western sections of the watershed are open areas consisting of golf courses, forest preserves and the Morton Arboretum. The south-central section is comprised of residential subdivisions and commercial enterprises. And the north-central section of the Lacey Creek watershed includes large highway junctions of Butterfield Road, I-355 and I-88. The Lacey Creek main stem has its origins at Fairview Avenue in Downers Grove, just east of Williams College. Flow proceeds to the west, passing through the Williams College campus, Lyman Woods Forest Preserve, and Highland Avenue. On the west side of Highland Avenue, Lacey Creek enters a single-family residential area and passes under such roads as Barneswood Drive, Saratoga Avenue, Venard Drive, Downers Drive, and Finley Road. The creek enters a conduit that passes under the I-88 / I-355 corridor, opening up on the west side in the Morton Arboretum. Lacey Creek passes from the Arboretum into the Hidden Lake Forest Preserve. Lacey Creek confluences with the East Branch DuPage River within the Hidden Lake Forest Preserve.

3.3.12.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Lacey Creek. Discharge-frequency data for the mouth of Lacey Creekwere developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963).


Discharges for the 10-year, 50-year, and 100-year floods for Lacey Creek, studied by the limited detail method were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. Much of Lacey Creek was determined by linear extrapolation of a log-probability graph of flood discharges computed for frequencies up to 100 years. Peak discharges for the upstream reaches of Lacey Creek were obtained by applying the square root of the drainage area ratio method to discharge values obtained from the HEC-1 computer model. This method consists of calculating upstream discharges from a known downstream station by multiplying the discharge values from that downstream station by the square root of the ratio of the drainage area of the upstream station in question to the drainage area of the downstream station. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBLA.1.

Table EBLA.1: Lacey Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Lacey Creek

- at mouth 4.80 450 720 860 1,180

3.3.12.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater


computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Water-surface profiles for Lacey Creek were developed using the USACE HEC-2 step-backwater computer model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Roughness coefficients (Manning’s “n”) for Lacey Creek were estimated by field inspection at the various cross sections. Table EBLA.2: Lacey Creek Manning’s “n” Values



Lacey Creek 0.040 - 0.060 0.040 - 0.080 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. The 100-year flood stage for streams studied by approximate methods was determined by solving Manning’s equation for depth of flow in the channel. These streams were inspected in the field to obtain stream cross-sections, and measurements at bridges and culverts.

3.3.12.4 Flood Boundaries To reference the flood boundaries for Lacey Creek, see Map Panels: 0509, 0607, 0608, 0803, 0901 and 0902. 3.3.12.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.12.6 Flood Profiles Please reference attached Flood Profile Sheets


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Lacey Creek (EBLA)EBLA0001 686 285 873 1.0 676.7 676.0 676.1 0.11 3 2

EBLA0002 2,483 185 623 1.4 677.0 677.0 677.1 0.11

EBLA0003 4,382 285 1,597 0.5 680.5 680.5 680.6 0.11 3

EBLA0004 4,804 700 956 0.9 680.7 680.7 680.8 0.11 3

EBLA0005 5,068 445 584 1.5 681.7 681.7 681.8 0.11 3

EBLA0006 6,109 450 465 1.9 683.5 683.5 683.6 0.11

EBLA0007 7,579 280 582 1.5 689.2 689.2 689.3 0.11

EBLA0008 8,760 215 1,641 0.4 691.5 691.5 691.5 0.01

EBLA0009 9,217 90 638 1.1 691.9 691.9 691.9 0.01

EBLA0010 10,165 60 135 5.1 692.0 692.0 692.0 0.01

EBLA0011 10,894 70 427 1.6 695.1 695.1 695.1 0.01

EBLA0012 11,989 85 439 1.6 696.5 696.5 696.5 0.01

EBLA0013 12,972 210 1,477 0.5 696.7 696.7 696.7 0.01

EBLA0014 14,000 1,020 3,412 0.2 696.8 696.8 696.8 0.01

EBLA0015 15,166 675 4,703 0.1 696.8 696.8 696.8 0.01

EBLA0016 16,831 125 540 1.0 697.2 697.2 697.3 0.11

EBLA0017 17,362 100 381 1.4 698.1 698.1 698.2 0.11

EBLA0018 17,785 155 373 1.4 699.0 699.0 699.1 0.11


AND INCORPORATED AREAS LACEY CREEK (EBLA)

In feet above confluence with East Branch DuPage River2 Elevation computed without consideration of backwater effects from East Branch DuPage River

3 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Lacey Creek (EBLA)EBLA0019 18,049 60 67 2.9 702.3 702.3 702.3 0.01


AND INCORPORATED AREAS LACEY CREEK (EBLA)

In feet above confluence with East Branch DuPage River2 Elevation computed without consideration of backwater effects from East Branch DuPage River


1

TAB

LE 5

655

660

665 665

670 670

675 675

680 680

685 685

690 690

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

LAC

EY

CR

EE

K (E

BLA

)

58P

EB

LA00

01

EB

LA00

02

EB

LA00

03

EB

LA00

04

EB

LA00

05

EB

LA00

06

CO

NFL

UE

NC

E W

ITH

EA

ST

BR

AN

CH

DU

PA

GE

RIV

ER

PR

IVA

TE R

OA

D

PR

IVA

TE R

OA

D

PR

IVA

TE R

OA

D

PR

IVA

TE R

OA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



665

670

675 675

680 680

685 685

690 690

695 695

700 700

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

LAC

EY

CR

EE

K (E

BLA

)

59P

EB

LA00

07

EB

LA00

08

EB

LA00

09

EB

LA00

10

EB

LA00

11

EB

LA00

12

EB

LA00

13

FIN

LEY

RO

AD

DO

WN

ER

S D

RIV

E

VE

NA

RD

DR

IVE

SA

RA

TOG

A A

VE

NU

E

BA

RN

ES

WO

OD

DR

IVE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


675

680

685 685

690 690

695 695

700 700

705 705

710 710

715 715

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

LAC

EY

CR

EE

K (E

BLA

)

60P

EB

LA00

14

EB

LA00

15

EB

LA00

16

EB

LA00

17

EB

LA00

18

EB

LA00

19

HIG

HLA

ND

AV

EN

UE

WIL

LIA

MS

CO

LLE

GE

PR

IVA

TE R

OA

D

FAIR

VIE

W A

VE

NU

ELI

MIT

OF

DE

TAIL

ED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.13 Prentiss Creek (EBPR)

3.3.13.1 Tributary Description Prentiss Creek is tributary to the East Branch DuPage River, joining the river in Woodridge at the Seven Bridges Golf Course. The Prentiss Creek watershed area, shared by the communities of Woodridge, Downers Grove, Lisle, Darien and Unincorporated DuPage County, totals 4507 acres. Much of Prentiss Creek watershed has a land use of suburban residential and commercial. The main stem of Prentiss Creek begins in Downers Grove in the residential area just east of Dunham Road. The main stem proceeds to the west primarily, passing through Dunham Road, Ruth Power’s Park, Springside Avenue, and Prentiss Avenue. A couple hundred feet downstream of Prentiss Avenue, the main stem is joined with the first Prentiss Creek branch traveling from the northeastern reaches of the watershed. The main stem continues to the west passing under Woodward Avenue, Puffer Road, I-355 (which is not included in the current FEMA FIS model), a few private roads, 63rd Street, Hobson Road, and a weir near 63rd Street. Shortly after this weir, the main stem joins the second Prentiss Creek Branch that drains the northern part of the watershed. The main stem proceeds to the west, sandwiched between subdivisions until it crosses under Route 53. After passing a few gabion weirs, Prentiss Creek main stem joins the East Branch DuPage River. The first branch, which drains the northeastern section of the watershed, begins in the Village of Downers Grove upstream of Springside Avenue. The branch proceeds to the west, on an intersecting course with the main stem, through such streets as Wells Drive, Priden Drive and Loomis Drive. The second, much smaller branch drains the north-central portions of the Prentiss watershed. The branch begins at the Meadows School in Woodridge and proceeds south through 59th Street. A mile beyond 59th Street, the second branch joins main stem Prentiss Creek. 3.3.13.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Prentiss Creek. Discharges for the 10-year, 50-year, and 100-year floods for Prentiss Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973).


The USGS stream gages used for the hydrologic analyses for the streams studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented below:

Table EBPR.1: USGS Stream Gages Used for Hydrologic Analysis of the Prentiss Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Prentiss Creek near Lisle 05540240 6.48 15

The results of the hydrologic analyses were submitted to the Illinois State Water Survey for review. The 100-year flood discharges computed for the streams studied in detail and the streams studied by limited detail in the unincorporated areas of DuPage County were approved by the SWS and were certified by the DWR. The discharges for Prentiss Creek were derived from a regional frequency analysis using two Illinois Division of Water Resources stage recording gages located on the East Branch DuPage River, and five damage index stations used in the above Chicago Metro Study. Of these damage index stations, three were located along St. Joseph Creek, and one each along the East Branch DuPage River and Armitage Ditch. The analysis of the two Division of Water Resources gages, no. D W-C-3 at Naperville in Will County and No. D W-C-4 near Lisle in DuPage County, with individual recording periods of 14 and 15 years, respectively, followed the standard log-Pearson Type III method as outlined by the Water Resources Council (U.S. Water Resources Council, 1967). For the damage index stations, synthetic frequency-discharge curves were derived using regionalized statistics developed in the Chicago Metro Study. Flood peak discharges were obtained from regional drainage area-peak discharge curves computed from the results of the above gage and station analyses. Discharges for the 500-year floods were determined by straight-line extrapolation of a log-probability curve of flood discharges computed for frequencies up to 100 years. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBPR.2.

Table EBPR.2: Prentiss Creek Summary of Discharges


Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Prentiss Creek

- at mouth 6.60 540 850 1,020 1,410 - at 63rd Street Bridge 3.97 420 665 795 1,100


Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface profiles of Prentiss Creek were computed through use of the USACE’s HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Profiles were determined for the 10-, 50-, 100-, and 500-year floods. Starting elevations at the downstream corporate limits for Prentiss Creek were determined from profiles of these streams computed for the FIS of the unincorporated areas of DuPage County (FEMA, 1982). Roughness coefficients (Manning’s “n”) for Prentiss Creek were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Refer to Table EBPR.3 for further information. Table EBPR.3: Prentiss Creek Manning’s “n” Values



Prentiss Creek 0.045 - 0.050 0.070 - 0.100 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain


unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. The 100-year flood stage for streams studied by approximate methods was determined by solving Manning’s equation for depth of flow in the channel. These streams were inspected in the field to obtain stream cross-sections, and measurements at bridges and culverts.

3.3.13.4 Flood Boundaries To reference the flood boundaries for Prentiss Creek, see Map Panels: 0803, 0805, 0806, 0809, 0904, 0905, 0907 and 0908. 3.3.13.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.13.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Prentiss Creek (EBPR)EBPR0001 6,589 169 585 1.7 664.8 664.8 664.8 0.01

EBPR0002 13,600 120 603 1.5 697.9 697.9 697.9 0.01 2

EBPR0003 14,395 100 419 2.2 699.7 699.7 699.7 0.01 2

EBPR0004 16,520 50 335 2.7 711.7 711.7 711.7 0.01

EBPR0005 17,057 45 108 8.3 717.7 717.7 717.7 0.01

EBPR0006 17,694 60 297 3.0 720.9 720.9 720.9 0.01

EBPR0007 18,280 130 1,113 0.5 722.2 722.2 722.21 2

EBPR0008 19,212 85 441 1.4 722.7 722.7 722.71 2

EBPR0009 21,015 95 409 1.5 730.0 730.0 730.0 0.01 2

EBPR0010 22,848 75 398 1.5 744.1 744.1 744.1 0.01 2

EBPR0011 23,151 45 96 6.3 744.1 744.1 744.1 0.01


AND INCORPORATED AREAS PRENTISS CREEK (EBPR)

In feet above East Branch DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

635

640

645 645

650 650

655 655

660 660

665

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PREN

TISS

CRE

EK (E

BPR)

61P

HOBS

ON R

OAD

CONF

LUEN

CE W

ITH


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


EAST

BRA

NCH

DUPA

GE R

IVER

FLOODING CONTROLLED BY EAST BRANCH DUPAGE RIVER 100-YEAR BACKWATER FROMEAST BRANCH DUPAGE RIVER

CULVERTS

665

645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

690 690

6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PREN

TISS

CRE

EK (E

BPR)

62P

EBPR

0001

STAT

E RO

UTE

53


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

12000 12500 13000 13500 14000 14500 15000 15500 16000 16500 17000 17500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PREN

TISS

CRE

EK (E

BPR)

63P

EBPR

0002

EBPR

0003

EBPR

0004

EBPR

0005

HOBS

ON R

OAD

PRIV

ATE

DRIV

E

PUFF

ER R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


705

710

715 715

720 720

725 725

730 730

735 735

740 740

745 745

17500 18000 18500 19000 19500 20000 20500 21000 21500 22000 22500 23000 23500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

PREN

TISS

CRE

EK (E

BPR)

64P

EBPR

0006

EBPR

0007

EBPR

0008

EBPR

0009

EBPR

0010

EBPR

0011

WOO

DWAR

E AV

ENUE

PREN

TISS

DRI

VE

SPRI

NGSI

DE A

VENU

E

DUNH

AM R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.14 Rott Creek (EBRC)

3.3.14.1 Tributary Description Rott Creek is a 3832-acre watershed that is tributary to the East Branch DuPage River. The communities that contribute watershed area to Rott Creek are: Naperville, Lisle, Wheaton and Unincorporated DuPage County. Rott Creek is located in the central section of DuPage County, and has varied land use characteristics. The headwater portion of Rott Creek shares equal land uses between undeveloped and residentially developed areas. The central section of the watershed has experienced booming growth with large commercial ventures such as Lucent Technologies and numerous hotels. The southern section of the watershed changes land use between high and low density residential, but as the watershed nears the East Branch River the land use changes to light commercial and park land. Rott Creek is a relatively long, single-branched tributary. The headwaters of Rott Creek can be found in Herrick Lake Forest Preserve. As Rott Creek proceeds to the south, it encounters newly developed sites upstream of Warrenville and Naperville Roads (Lucent Technologies). The creek passes east under Naperville Road and enters a series of detention ponds. Rott Creek turns to the south, passing under Warrenville Road, I-88, Old Tavern Road, Ogden Avenue, and Wellington Avenue. Rott Creek turn abruptly to the east and continues to pass under Keller Street, Beaubien Boulevard, Arlington Avenue, the Burlington Northern Railroad, Yackley Avenue, and Varsity Drive before confluencing with the East Branch DuPage River at the Lisle Community Park. 3.3.14.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Rott Creek. For Rott Creek, synthetic frequency-discharge curves were derived for three stations used in the Chicago Metropolitan study using regionalized statistics developed in that study and assuming zero skew. Discharges for the 500-year floods of all streams were determined by linear extrapolation of a log-probability graph plotted for calculated peak discharges. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBRC.1.

Table EBRC.1: Rott Creek Summary of Discharges Summary of Discharges


Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Rott Creek

- at mouth 5.06 405 640 745 1,025 - at Yackley Avenue 4.94 395 620 725 995 - below Old Tavern Rd 3.91 275 430 505 695 - below I-88 3.44 188 269 306 382

3.3.14.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface elevations of floods of the selected recurrence intervals were computed through use of the COE HEC-2 step-backwater computer model. Starting water-surface elevations for Rott Creek were determined using the slope/area method. For the areas studied by approximate methods, 100-year flood water-surface elevations were determined by solving Manning’s equation for depth of flow in the channel. These streams were field surveyed to obtain typical stream cross-sections, average stream channel slope, and Manning’s “n” values. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.14.4 Flood Boundaries


To reference the flood boundaries for Rott Creek, see Map Panels: 0409, 0507, 0508, 0703, 0801, 0802 and 0805. 3.3.14.5 Floodways No floodway was delineated on Rott Creek above the East-West Tollway, as the recent channel improvements in this area contain the 100-year flood. Please reference attached Floodway Data Tables for further information. 3.3.14.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Rott Creek (EBRC)EBRC0001 1,731 256 158 4.7 664.5 658.9 659.0 0.11 2 2

EBRC0002 2,505 108 305 2.4 668.4 668.4 668.4 0.01

EBRC0003 3,206 47 135 5.5 670.0 670.0 670.1 0.11

EBRC0004 4,108 44 121 6.0 675.5 675.5 675.5 0.01

EBRC0005 4,330 37 124 5.8 677.1 677.1 677.1 0.01

EBRC0006 6,390 59 151 4.8 687.2 687.2 687.3 0.11

EBRC0007 7,204 65 185 3.9 692.1 692.1 692.2 0.11

EBRC0008 7,743 94 249 2.9 694.2 694.2 694.3 0.11

EBRC0009 11,200 195 513 1.4 711.4 711.4 711.5 0.11

EBRC0010 12,215 50 133 5.4 717.7 717.7 717.7 0.01

EBRC0011 12,425 154 425 1.7 720.8 720.8 720.8 0.01

EBRC0012 13,190 120 333 2.2 722.2 722.2 722.3 0.11

EBRC0013 13,407 120 399 1.8 722.5 722.5 722.6 0.11

EBRC0014 13,978 83 245 2.1 722.8 722.8 722.8 0.01

EBRC0015 14,215 186 585 0.9 724.6 724.6 724.6 0.01

EBRC0016 14,465 278 1,205 0.4 724.6 724.6 724.6 0.01

EBRC0017 15,498 354 1,068 0.5 724.6 724.6 724.6 0.01

EBRC0018 16,162 195 532 0.9 724.7 724.7 724.7 0.01


AND INCORPORATED AREAS ROTT CREEK (EBRC)

In feet above confluence with East Branch DuPage River2 Elevations computed without consideration of backwater effects from East Branch DuPage River

1

TAB

LE 5

630

640

650 650

660 660

670 670

680 680

690 690

700 700

710 710

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

RO

TT C

RE

EK

(EB

RC

)

65P

EB

RC

0001

EB

RC

0002

EB

RC

0003

EB

RC

0004

EB

RC

0005

EB

RC

0006

CO

NFL

UE

NC

E W

ITH

EA

ST

BR

AN

CH

DU

PA

GE

RIV

ER

PR

IVA

TE D

RIV

E

VA

RS

ITY

DR

IVE

YA

CK

LEY

AV

EN

UE

YA

CK

LEY

AV

EN

UE

RA

ILR

OA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



CULVERT

CULVERT

660

670

680 680

690 690

700 700

710 710

720 720

730 730

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

RO

TT C

RE

EK

(EB

RC

)

66P

EB

RC

0007

EB

RC

0008

EB

RC

0009

EB

RC

0010

EB

RC

0011

BU

RLI

NG

TON

AV

EN

UE

BE

AU

BIE

N R

OA

D

FOO

TBR

IDG

E

KE

LLE

R S

TRE

ET

BU

RLI

NG

TON

AV

EN

UE

FEN

DE

R A

VE

NU

EO

GD

EN

AV

EN

UE

FEN

DE

R A

VE

NU

E


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


690

700

710 710

720 720

730 730

740 740

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

RO

TT C

RE

EK

(EB

RC

)

67P

EB

RC

0012

EB

RC

0013

EB

RC

0014

EB

RC

0015

EB

RC

0016

EB

RC

0017

EB

RC

0018

FOO

T B

RID

GE

OLD

TA

VE

RN

RO

AD

EA

ST-

WE

ST

TOLL

WA

Y (I

-88)


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

690

700

710 710

720 720

730 730

740 740

18000 18500 19000 19500 20000

ELE

VA

TIO

N IN

FE

ET

(NG

VD

29)


FED

ER

AL

EM

ER

GE

NC

Y M

AN

AG

EM

EN

T A

GE

NC

Y

DU

PA

GE

CO

UN

TY, I

LA

ND

INC

OR

PO

RA

TED

AR

EA

S

FLO

OD

PR

OFI

LES

RO

TT C

RE

EK

(EB

RC

)

68P

WA

RR

EN

VIL

LE R

OA

D

PR

IVA

TE R

OA

D

NA

PE

RV

ILLE

RO

AD

LIM

IT O

F D

ETA

ILE

D S

TUD

Y


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.3.15 St. Joseph’s Creek (EBSJ)

3.3.15.1 Tributary Description St. Joseph’s Creek is a 7203-acre watershed tributary to the East Branch DuPage River. The communities that contribute watershed area to the St. Joseph Creek watershed are: Lisle, Downers Grove, Westmont, Darien and Unincorporated DuPage County. This large watershed has a primary land use of suburban residential, but there are more open areas found in the upper reaches of the watershed, and along the I-355 corridor. St. Joseph Creek is broken down into several segments: St. Joseph Creek (Main Stem), the St. Joseph Creek North Branch, St. Joseph Creek South Branch, St. Joseph Creek Tributary, St. Joseph Creek Tributary 1 (A), and St. Joseph Creek Tributary 2 (B). Each segment shall be described in detail. St. Joseph Creek headwaters are found on the southeast corner of 63rd Street and Williams Street in the Village of Westmont. The Creek proceeds on a northwesterly course passing under such roads as Williams Street, 63rd Street, and 61st Street. St. Joseph changes bearing to the northeast passing under 60th Street and 59th Street. It is north of 59th Street that St. Joseph Creek enters Westmont’s Twin Lakes Park, and confluences with St. Joseph Tributary. St. Joseph Creek exits the park to the northwest, entering the Twin Lakes Golf Course and the King Arthur Court apartment complex detention system. The creek emerges on the west side of Cumnor Avenue, and runs parallel to 56th Street to Fairview Avenue. After passing under Fairview, St. Joseph Creek enters Patriot Park where the creek confluences with the St. Joseph Creek South Branch. The Main Stem continues to the north passing under 55th Street and enters a long conduit at Hill Street that passes underneath an elementary school and parking lot, which exits on the east side of Blodgett Avenue. Main Stem St. Joe enters another conduit at Blodgett Avenue that exits on the north side of Maple Avenue. The Main Stem confluences with St. Joseph Creek North Branch and enters a 16-ft diameter conduit that passes underneath the Downers Grove business district. This large conduit exits on the west side of Carpenter Street. The Main Stem continues to the west through less dense residential areas, passing under such roads as Brookbank Road and Jacqueline Drive before entering the Maple Grove Forest Preserve. Upon exiting the Forest Preserve, St. Joe passes under Lee Avenue, Belmont Road, Curtiss Avenue and Walnut Avenue. After passing by the Downers Grove Wastewater Treatment Plant, on the west side of Walnut Avenue, the Main Stem winds its way through relatively untouched terrain until it passes underneath I-355. The Main Stem confluences with St. Joseph Creek Tributary 2 (B), continues west for about one half mile, where it changes bearing to the northwest, passing


under the Burlington Northern Railroad, Ogden Avenue and Center Street. On the downstream side of Center Street, St. Joseph Creek confluences with the St. Joseph Creek Tributary 1 (A). The Main Stem continues to the west passing under Main Street (Lisle), Route 53 and Dumoulin Avenue. Just west of this location, St. Joseph Creek joins the East Branch DuPage River. St. Joseph Creek Tributary 1 (A) begins in corporate ponds located on the north side of Warrenville Road. The branch flows south passing under Warrenville Road, entering another corporate pond area. Tributary 1 (A) exits the pond under Oldham Avenue, passes closely alongside some residential houses, flows under Buckley Avenue and the Middleton/Center intersection, on the downstream side of which the branch confluences with Main Stem St. Joseph Creek. St. Joseph Creek Tributary 2 (B) begins in a relatively open area on the east side of I-355, south of Ogden Avenue. The branch flows to the southwest, passing underneath I-355 and the Burlington Northern Railroad, on the downstream side of which the branch confluences with Main Stem St. Joseph Creek. St. Joseph Creek North Branch begins on the east side of Cumnor Road (north of the Burlington Northern Railroad tracks). The branch proceeds to the southwest passing under such roads as Florence Avenue, Hummer Park Drive, Fairview Avenue, Austin Street, Rogers Street, and Douglas Road. The branch passes under the Burlington Northern Railroad and on the downstream side confluences with the St. Joseph Creek Main Stem. St. Joseph Creek South Branch begins in a depressional area on the south side of 59th Street, east of Middaugh Street in Downers Grove. The overall flow of the South Branch is to the northeast, passing under such roads as 59th Street, Brookbank Road, Carpenter Street, Main Street, Webster Street, Washington Street, Lyman Avenue and Fairmount Avenue. The South Branch then enters Patriot Park and confluences with St. Joseph Creek Main Stem. St. Joseph Creek Tributary is a short branch that begins on the south side of 60th Street in a residential detention pond. The branch flows to the north, under 60th Street, into a residential/corporate pond. The branch continues north underneath 59th Street into Twin Lakes Park where it encounters the Main Stem of St. Joseph Creek. 3.3.15.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for St. Joseph’s Creek.


Discharges for the 10-year, 50-year, and 100-year floods for St. Joseph Creek studied by the limited detail method were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses for the streams studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented below in Table EBSJ.1.

Table EBSJ.1: USGS Stream Gages Used for Hydrologic Analysis of St. Joseph’s Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) St. Joseph’s Creek at Lisle 05540200 11.80 15 Discharges for the 500-year flood for South Branch St. Joseph Creek were determined by linear extrapolation of a log-probability graph of flood discharges computed for frequencies up to 100 years.

For St. Joseph Creek, synthetic frequency-discharge curves were derived for three stations used in the Chicago Metropolitan study using regionalized statistics developed in that study and assuming zero skew. Discharges for the 10-, 50-, 100-, and 500-year floods on St. Joseph Creek in the Village of Westmont were derived by extrapolation of discharge-drainage area relationship for the creek in Downers Grove. Discharges for Tributaries 1, 2, and 3 in Lisle were derived from DWR multiple regression equations (State of Illinois, 1973).

The discharges for St. Joseph Creek Tributary were derived using the State Standard Method. Discharges for the 10- and 100-year floods were computed using regional equations for Illinois (U.S. Department of the Interior, 1974). Hydrologic and hydraulic analysis of the detention ponds on the stream showed that their effect on floods greater than or equal to the 10-year event is minimal. Therefore, no adjustments were applied to the discharges developed from the regional equations. Discharges for the 10- and 100-year floods were plotted on log-normal probability paper. The 50- and 500-year flood discharges were estimated by straight line interpolation and extrapolation, respectively. The 100-year discharges estimated for the two detailed study streams were sent to the SWS for


review. The discharges were approved by the SWS and certified by the DOWR. Data are located in a repository of flood-related data administered by the SWS.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBSJ.2.

Table EBSJ.2: St Joseph Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr St. Joseph Creek - North Branch

- at confluence with St. Joseph Creek 2.05 250 395 465 650 St Joseph Creek - South Branch

- at confluence with St. Joseph Creek 0.75 180 285 335 465 St Joseph Creek - Tributary

- at confluence with St. Joseph Creek 0.30 54 87 101 140 St Joseph Creek - Tributary 1(a)

- at mouth 0.50 125 195 230 320 - above Warrenville Rd 0.20 55 90 105 145

St Joseph Creek - Tributary 2(b)

- at Burlington Northern Railroad 0.47 145 230 275 385

- at Ogden Avenue 0.19 90 145 175 245 St. Joseph Creek - at mouth 11.80 730 1,160 1,365 1,900 - at Main Street 11.10 710 1,125 1,320 1,830 - at Burlington Northern Railroad 10.40 690 1,090 1,290 1,770 - d/s of Maple Avenue 3.28 405 645 760 1,055 - at Cumnor Avenue 1.65 290 460 540 750 - at 63rd Street 0.80 205 330 390 515 - d/s of 55th Street 2.83 155 250 295 405


3.3.15.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface profiles for North Branch St. Joseph Creek and South Branch St. Joseph Creek were developed using the USACE HEC-2 step-backwater computer model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973).

For North Branch and South Branch of St. Joseph Creek, starting elevations were determined from concurrent flowlines with the main stem.

Roughness coefficients (Manning’s “n”) for North Branch St. Joseph Creek and South Branch St. Joseph Creek were estimated by field inspection at the various cross sections. Cross sections for St. Joseph Creek, Tributary 1 (A) and Tributary 2 (B) were field surveyed. For St. Joseph Creek, the below water sections were obtained by field measurement and the overbank sections were obtained from aerial photographs (Northeastern Illinois Planning Commission, 1975). In all cases, cross sections were located at close intervals above and below bridges and culverts in order to compute the significant backwater effects of these structures.

Water-surface elevations of floods of the selected recurrence intervals were computed for St. Joseph Creek, Tributary 1 (A) and Tributary 2 (B) through use of the USACE HEC-2 step-backwater computer model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973).

Starting water-surface elevations for St. Joseph Creek were calculated using the slope/area method.


Roughness coefficients for St. Joseph Creek, Tributary 1 (A) and Tributary 2 (B) were estimated by field inspection of the streams and floodplains.

Cross-section data for St. Joseph Creek Tributary were obtained from field measurements.

Hydraulic analyses for the St. Joseph Creek Tributary were made using the backwater program WSP-2 of the U.S. Department of Agriculture, Soil Conservation Service (SCS) (U.S. Department of Agriculture, 1976). Mathematical relationships used in the model include the standard step method for backwater computations which estimates total energy at each cross section and accounts for friction losses between sections using Manning’s formula. The model requires discharge, cross-section geometry, bridge geometry, starting water-surface elevations, and roughness data to simulate flood flow conditions. The starting water-surface elevations for St. Joseph Creek Tributary are the water-surface elevations on St. Joseph Creek at the confluence of the two streams. Roughness coefficients (Manning’s “n”) for St. Joseph Creek were estimated from field inspection at cross-section locations, and from model calibration based on high water marks. Refer to Table EBSJ.3 for further details.

Table EBSJ.3: St. Joseph Creek Manning’s “n” Values



St. Joseph Creek - North Branch 0.035 0.070 St. Joseph Creek - South Branch 0.035 0.060

St. Joseph Creek 0.028 - 0.038 0.035 - 0.050 St. Joseph Creek Tributary 0.028 - 0.038 0.035 - 0.050 Tributary 1 (A) 0.035 - 0.040 0.060 - 0.080 Tributary 2 (B) 0.035 - 0.040 0.060 - 0.080

The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study.


All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.15.4 Flood Boundaries To reference the flood boundaries for St. Joseph Creek, see Map Panels: 0608, 0802, 0803, 0806, 0901, 0902, 0904 and 0905. 3.3.15.5 Floodways

The St. Joseph Creek floodway was determined using the HUD-15 computer program. Please reference attached Floodway Data Tables for further information. 3.3.15.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


St. Joseph Creek (EBSJ)

EBSJ0001 897 80 441 3.1 668.6 667.8 667.9 0.11 2

EBSJ0002 1,256 167 623 2.2 669.2 669.2 669.2 0.01

EBSJ0003 1,419 114 390 3.5 669.2 669.2 669.2 0.01

EBSJ0004 1,736 114 435 3.1 669.6 669.6 669.6 0.01

EBSJ0005 2,142 54 398 3.4 670.0 670.0 670.0 0.01

EBSJ0006 3,173 47 558 2.4 671.0 671.0 671.1 0.11

EBSJ0007 3,537 83 376 3.5 671.0 671.0 671.01

EBSJ0008 3,960 64 387 3.4 671.6 671.6 671.7 0.11

EBSJ0009 4,488 120 479 2.8 673.7 673.7 673.8 0.11

EBSJ0010 5,016 149 452 2.9 674.1 674.1 674.2 0.11 4

EBSJ0011 5,334 47 181 7.3 674.4 674.4 674.4 0.01

EBSJ0012 5,492 152 1,050 1.3 675.6 675.6 675.6 0.01 4

EBSJ0013 5,702 103 595 2.2 676.4 676.4 676.5 0.11 4

EBSJ0014 6,547 127 479 2.7 676.5 676.5 676.6 0.11

EBSJ0015 6,969 47 267 4.8 676.7 676.7 676.8 0.11

EBSJ0016 7,920 69 332 3.9 678.4 678.4 678.5 0.11

EBSJ0017 8,923 70 375 3.4 680.0 680.0 680.1 0.11


AND INCORPORATED AREAS ST. JOSEPH CREEK (EBSJ)

In feet above confluence with East Branch DuPage River2 Elevation considered without backwater effects from East Branch DuPage River

3 Floodway coincident with channel banks4 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



EBSJ0018 9,291 52 329 3.9 680.5 680.5 680.6 0.11

EBSJ0019 10,021 50 310 4.2 681.5 681.5 681.5 0.01

EBSJ0020 10,400 50 310 4.2 681.9 681.9 681.9 0.01

EBSJ0021 12,159 50 450 2.9 684.0 684.0 684.0 0.01

EBSJ0022 12,828 40 1,113 1.2 688.0 688.0 688.1 0.11

EBSJ0023 14,159 60 464 2.7 690.8 690.8 690.9 0.11

EBSJ0024 15,054 170 446 2.8 692.7 692.7 692.8 0.11

EBSJ0025 16,016 148 745 1.7 694.7 694.7 694.8 0.11

EBSJ0026 18,304 85 844 1.5 696.8 696.8 696.9 0.11

EBSJ0027 19,142 105 876 1.4 697.4 697.4 697.5 0.11

EBSJ0028 19,834 140 730 1.7 697.9 697.9 698.0 0.11

EBSJ0029 20,362 190 1,017 1.2 698.4 698.4 698.5 0.11

EBSJ0030 21,589 110 504 2.5 699.7 699.7 699.8 0.11

EBSJ0031 22,223 105 239 5.2 700.2 700.2 700.3 0.11

EBSJ0032 22,440 45 718 1.7 701.3 701.3 701.4 0.11

EBSJ0035 27,625 89 3.3 709.8 709.8 709.8 0.01 3

EBSJ0036 27,998 98 3.0 710.1 710.1 710.1 0.01 3





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



EBSJ0037 28,689 93 3.2 715.0 715.0 715.0 0.01 3

EBSJ0038 29,581 51 228 1.3 715.3 715.3 715.4 0.11

EBSJ0039 30,741 146 342 1.9 718.1 718.1 718.2 0.11

EBSJ0040 31,582 118 352 1.9 719.5 719.5 719.6 0.11

EBSJ0041 32,253 98 298 2.2 719.8 719.8 719.9 0.11

EBSJ0042 33,189 83 564 1.2 721.0 721.0 721.1 0.11

EBSJ0043 35,047 301 1,435 0.4 726.1 726.1 726.2 0.11

EBSJ0044 35,772 170 198 2.5 727.6 727.6 727.7 0.11

EBSJ0045 36,474 124 361 1.3 730.6 730.6 730.7 0.11

EBSJ0046 38,687 53 185 2.2 734.1 734.1 734.2 0.11





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Tributary 1 (A) (EBSJ)EBSJ0047 97 7 22 10.2 670.8 670.5 670.5 0.01 2

EBSJ0048 265 89 145 1.6 674.3 674.3 674.3 0.01

EBSJ0049 355 13 33 7.1 675.3 675.3 675.3 0.01

EBSJ0050 476 15 264 0.9 678.6 678.6 678.6 0.01

EBSJ0051 775 15 29 7.9 679.6 679.6 679.6 0.01

EBSJ0052 1,227 65 122 1.9 682.5 682.5 682.5 0.01

EBSJ0053 1,484 59 217 1.1 684.3 684.3 684.3 0.01

EBSJ0054 2,139 51 65 3.5 689.5 689.5 689.5 0.01

EBSJ0055 2,566 180 512 0.4 696.1 696.1 696.2 0.11 3

EBSJ0056 3,156 88 32 3.3 699.4 699.4 699.5 0.11

EBSJ0057 4,030 210 65 1.6 710.8 710.8 710.8 0.01 3

EBSJ0058 5,302 50 29 3.6 728.1 728.1 728.1 0.01


AND INCORPORATED AREAS TRIBUTARY 1 (A) (EBSJ)

In feet above confluence with St. Joseph Creek2 Elevation computed without consideration of backwater effects from St. Joseph Creek

3 Actual floodway width cannot be shown on the FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Tributary 2 (B) (EBSJ)EBSJ0059 195 65 530 0.5 685.2 685.2 685.3 0.11

EBSJ0060 935 70 321 0.9 685.2 685.2 685.3 0.11

EBSJ0061 1,662 104 186 1.5 685.4 685.4 685.5 0.11 2

EBSJ0062 1,780 75 68 4.1 687.3 687.3 687.4 0.11 2

EBSJ0063 2,012 13 31 9.0 695.0 695.0 695.0 0.01

EBSJ0064 2,158 25 66 4.2 697.2 697.2 697.2 0.01

EBSJ0065 2,421 19 50 5.5 699.8 699.8 699.8 0.01


AND INCORPORATED AREAS TRIBUTARY 2 (B) (EBSJ)

In feet above confluence with St. Joseph Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain.

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


North Branch St. Joseph Creek (EBSJ)

EBSJ0066 264 23 95 4.9 713.1 713.1 713.2 0.11

EBSJ0067 898 21 69 6.7 715.6 715.6 715.6 0.01

EBSJ0068 1,636 60 232 2.0 721.9 721.9 721.9 0.01

EBSJ0069 2,265 121 267 1.7 722.3 722.3 722.3 0.01

EBSJ0070 2,497 224 437 1.1 722.5 722.5 722.6 0.11

EBSJ0071 2,957 139 353 1.3 723.2 723.2 723.3 0.11

EBSJ0072 3,432 27 76 6.1 723.9 723.9 724.0 0.11

EBSJ0073 3,749 100 832 0.6 725.9 725.9 725.9 0.01 2


AND INCORPORATED AREAS NORTH BRANCH ST. JOSEPH CREEK (EBSJ)

In Feet above confluence with St. Joseph Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


South Branch St. Joseph Creek (EBSJ)

EBSJ0074 211 288 1,528 0.2 718.2 718.2 718.3 0.11 2

EBSJ0075 581 438 2,294 0.2 718.2 718.2 718.3 0.11 2

EBSJ0076 986 177 1,080 0.3 718.2 718.2 718.3 0.11 2

EBSJ0077 1,320 231 924 0.4 718.3 718.3 718.4 0.11

EBSJ0078 1,465 305 1,441 0.2 718.3 718.3 718.4 0.11

EBSJ0079 1,810 139 265 1.3 718.9 718.9 719.0 0.11

EBSJ0080 2,474 80 147 2.3 723.8 723.8 723.8 0.01

EBSJ0081 3,050 39 52 6.4 726.9 726.9 726.9 0.01

EBSJ0082 3,684 121 119 2.8 731.3 731.3 731.4 0.11

EBSJ0083 4,328 88 296 1.1 739.2 739.2 739.3 0.11

EBSJ0084 4,380 93 199 1.7 739.3 739.3 739.4 0.11

EBSJ0085 4,481 87 317 1.0 739.4 739.4 739.5 0.11

EBSJ0086 5,016 43 108 3.1 743.4 743.4 743.5 0.11

EBSJ0087 5,069 64 142 2.4 744.0 744.0 744.1 0.11

EBSJ0088 5,122 84 194 1.7 744.4 744.4 744.5 0.11

EBSJ0089 5,388 102 209 1.6 745.7 745.7 745.8 0.11

EBSJ0090 6,766 100 969 0.3 747.8 747.8 747.9 0.11


AND INCORPORATED AREAS SOUTH BRANCH ST. JOSEPH CREEK (EBSJ)

In feet above confluence with St. Joseph Creek2 Backwater from St. Joseph Creek

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


South Branch St. Joseph Creek (EBSJ)

EBSJ0091 7,117 204 330 1.0 747.8 747.8 747.9 0.11

EBSJ0092 7,595 179 416 0.8 748.0 748.0 748.1 0.11


AND INCORPORATED AREAS SOUTH BRANCH ST. JOSEPH CREEK (EBSJ)

In feet above confluence with St. Joseph Creek2 Backwater from St. Joseph Creek

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


St. Joseph Creek Tributary (EBSJ)

EBSJ0093 744 39 52 1.9 728.4 728.4 728.5 0.11

EBSJ0094 2,804 51 44 1.3 731.3 731.3 731.4 0.11


AND INCORPORATED AREAS ST. JOSEPH CREEK TRIBUTARY (EBSJ)

In feet above confluence with St. Joseph Creek1

TAB

LE 5

645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

690 690

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

69P

EBSJ

0001

EBSJ

0002

EBSJ

0003

EBSJ

0004

EBSJ

0005

EBSJ

0006

EBSJ

0007

EBSJ

0008

EBSJ

0009

EBSJ

0010

EBSJ

0011

EBSJ

0012

EBSJ

0013

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

DUM

OULI

N AV

ENUE

LINC

OLN

AVEN

UE(S

TATE

HIG

HWAY

53)

MAI

N ST

REET

CONF

LUEN

CE O

F TR

IBUT

ARY

1 (A

)CE

NTER

STR

EET

OGDE

N AV

ENUE

(U.S

. HIG

HWAY

34)

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



CULVERT

655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

70P

EBSJ

0014

EBSJ

0015

EBSJ

0016

EBSJ

0017

EBSJ

0018

EBSJ

0019

EBSJ

0020

EBSJ

0021

EBSJ

0022

CONF

LUEN

CE O

F TR

IBUT

ARY

2 (B

)

WAL

NUT

AVEN

UE

CURT

ISS

STRE

ET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

675

680 680

685 685

690 690

695 695

700 700

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

71P

EBSJ

0023

EBSJ

0024

EBSJ

0025

EBSJ

0026

EBSJ

0027

BELM

ONT

ROAD

LEE

AVEN

UE

PRIV

ATE

DRIV

E


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

675

680 680

685 685

690 690

695 695

700 700

705 705

19500 20000 20500 21000 21500 22000 22500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

72P

EBSJ

0028

EBSJ

0029

EBSJ

0030

EBSJ

0031

EBSJ

0032

JACQ

UELI

NE D

RIVE

BROO

KBAN

K RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

73P

EBSJ

0035

EBSJ

0036

EBSJ

0037

EBSJ

0038

EBSJ

0039

EBSJ

0040

EBSJ

0041

LIM

IT O

F DE

TAIL

ED S

TUDY

MAC

KIE

AVEN

UE

NORT

H BR

ANCH

ST.

JOS

EPH

CREE

K

MAP

LE A

VENU

E

BLOD

GETT

AVE

NUE

GRAN

D AV

ENUE

HILL

STR

EET

55TH

STR

EET

GRAN

D AV

ENUE

BERM

SOUT

H BR

ANCH

ST.

JOS

EPH

CREE

K

FAIR

VIEW

AVE

NUE

DEER

PATH

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F

CONF

LUEN

CE O

F

CULVERT

CULVERT

CULVERT

CULVERT

700

705

710 710

715 715

720 720

725 725

730 730

735 735

32500 33000 33500 34000 34500 35000 35500 36000 36500 37000 37500 38000 38500 39000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

74P

EBSJ

0042

EBSJ

0043

EBSJ

0044

EBSJ

0045

CUM

NOR

ROAD

KING

ART

HUR

COUR

T CR

OSSI

NG

EASY

ACR

ES G

OLF

COUR

SE C

ULVE

RT

57TH

STR

EET/

WIL

LIAM

S ST

REET

JAM

ES D

RIVE

CONF

LUEN

CE O

F ST

. JOS

PEH

CREE

K TR

IBUT

ARY

59TH

STR

EET

WIL

LIAM

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

715

720

725 725

730 730

735 735

740 740

38000 38500 39000 39500 40000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

(EBS

J)

75P

EBSJ

0046

61ST

STR

EET

63RD

STR

EET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH ST. JOSEPH CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

TRIB

UTAR

Y 1

(A) (

EBSJ

)

76P

EBSJ

0047

EBSJ

0048

EBSJ

0049

EBSJ

0050

EBSJ

0051

EBSJ

0052

EBSJ

0053

EBSJ

0054

EBSJ

0055

CONF

LUEN

CE W

ITH

ST. J

OSEP

H CR

EEK

CENT

ER S

TREE

TM

IDDL

ETON

AVE

NUE

FOOT

BRID

GE

FOOT

BRID

GE

BUCK

LEY

AVEN

UE

WAR

RENV

ILLE

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

TRIB

UTAR

Y 1

(A) (

EBSJ

)

77P

EBSJ

0056

EBSJ

0057


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50- AND 500-YEAR PROFILESARE TOO CLOSE TO THE 100-YEAR

ELEVATIONS TO BE SHOWN SEPARATELY

700

705

710 710

715 715

720 720

725 725

730 730

4500 4700 4900 5100 5300 5500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

TRIB

UTAR

Y 1

(A) (

EBSJ

)

78P

EBSJ

0058

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50- AND 500-YEAR PROFILESARE TOO CLOSE TO THE 100-YEARELEVATIONS TO BE SHOWN SEPARATELY

660

665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

705 705

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

TRIB

UTAR

Y 2

(B) (

EBSJ

)

79P

EBSJ

0059

EBSJ

0060

EBSJ

0061

EBSJ

0062

EBSJ

0063

EBSJ

0064

EBSJ

0065

CONF

LUEN

CE W

ITH

ST. J

OSEP

H CR

EEK

RAIL

ROAD

FOOT

BRID

GE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM ST. JOSEPH CREEK

690

695

700 700

705 705

710 710

715 715

720 720

725 725

730 730

0 500 1000 1500 2000 2500 3000 3500 4000 4500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

NORT

H BR

ANCH

ST.

JOS

EPH

CREE

K (E

BSJ)

80P

EBSJ

0066

EBSJ

0067

EBSJ

0068

EBSJ

0069

EBSJ

0070

EBSJ

0071

EBSJ

0072

EBSJ

0073

CONF

LUEN

CE W

ITH

ST. J

OSEP

H CR

EEK

RAIL

ROAD

CONCRETE VERTICAL

DOUG

LAS

ROAD

ROGE

R ST

REET

AUST

IN S

TREE

T

FAIR

VIEW

AVE

NUE

WIL

COX

AVEN

UE

FLOR

ENCE

AVE

NUE

CUM

NOR

ROAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


DROP INTO CULVERTUNDER RAILROAD

CULVERT

CULVERT

THE 50-YEAR FLOOD PROFILE IS

ELEVATION TO BE SHOWN SEPARATELYTOO CLOSE TO THE 100-YEAR

695

700

705 705

710 710

715 715

720 720

725 725

730 730

735 735

0 500 1000 1500 2000 2500 3000 3500 4000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SOUT

H BR

ANCH

ST.

JOS

EPH

CREE

K (E

BSJ)

81P

EBSJ

0074

EBSJ

0075

EBSJ

0076

EBSJ

0077

EBSJ

0078

EBSJ

0079

EBSJ

0080

EBSJ

0081

EBSJ

0082

CONF

LUEN

CE W

ITH

ST. J

OSEP

H CR

EEK

FAIR

MOU

NT A

VENU

E

LYM

AN A

VENU

E

WAS

HING

TON

STRE

ET

WEB

STER

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM ST. JOSEPH CREEK

THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR ELEVATION TO

BE SHOWN SEPARATELY

720

725

730 730

735 735

740 740

745 745

750 750

4000 4500 5000 5500 6000 6500 7000 7500 8000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SOUT

H BR

ANCH

ST.

JOS

EPH

CREE

K (E

BSJ)

82P

EBSJ

0083

EBSJ

0084

EBSJ

0085

EBSJ

0086

EBSJ

0087

EBSJ

0088

EBSJ

0089

EBSJ

0090

EBSJ

0091

EBSJ

0092

MAI

N ST

REET

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

E

PRIV

ATE

DRIV

EPR

IVAT

E DR

IVE

PRIV

ATE

DRIV

ECA

RPEN

TER

STRE

ET

BROO

KBAN

K AV

ENUE

59TH

STR

EET

MID

DAUG

H RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR ELEVATION TO

BE SHOWN SEPARATELY

710

715

720 720

725 725

730 730

735 735

0 500 1000 1500 2000 2500 3000 3500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

ST. J

OSEP

H CR

EEK

TRIB

UTAR

Y (E

BSJ)

83P

EBSJ

0093

EBSJ

0094

CONF

LUEN

CE W

ITH

ST. J

OSEP

H CR

EEK

59TH

STR

EET

60TH

STR

EET

61ST

STR

EET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

3.3.16 Swift Meadows (EBSM)

3.3.16.1 Tributary Description

Swift Meadows is a 600-acre watershed tributary to the East Branch DuPage River. The communities that contribute watershed area to this tributary are Bloomingdale, Addison and Unincorporated DuPage County. The land use of the tributary is commercial / industrial in the headwaters, open prairie in the central sections and low density residential near the confluence with the East Branch DuPage River. Swift Meadows Main Stem begins within the Swift Meadows Forest Preserve, found on the north side of Army Trail Road, west of Walter Drive. The Main Stem flows to the southwest where it confluences with the Walter Drive West Ditch. The Main Stem flows to the south, passes underneath Army Trail Road, eventually confluencing with the East Branch DuPage River. The Walter Drive West Ditch starts on the north side of Byron Avenue. The ditch passes under Byron, flows on the west side of Walter Avenue for on quarter mile where it confluences with the Swift Meadows Main Stem. 3.3.16.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge frequency relationships for floods of the selected recurrence intervals for each flooding source studies in detail affecting the community. Discharge-frequency data for East Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). 3.3.16.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the East Branch DuPage River were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood


elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for East Branch DuPage River were obtained by field measurement.

The 100-year water-surface elevation on the East Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Since no formal study was completed on Swift Meadows Tributary, the East Branch DuPage River 100-yr elevation information, determined through the above methods, at the location of the junction between the East Branch DuPage River and Swift Meadows Tributary is used for backwater effects on Swift Meadows Tributary. In addition to the determined backwater zone information, the unnumbered A-zone boundary was further formed through local studies and the USGS Flood of Record Maps. 3.3.16.4 Flood Boundaries To reference the flood boundaries for Swift Meadows Tributary, see Map Panels: 0206 and 0209. 3.3.16.5 Floodways No floodway information is available. 3.3.16.6 Flood Profiles No flood profile information is available.


3.3.17 22nd Street (EBTS)

3.3.17.1 Tributary Description 22nd Street Tributary is a 494-acre watershed tributary to the East Branch DuPage River. Lombard and Unincorporated DuPage County contribute watershed area to the 22nd Street Tributary. The overall land use of the watershed is highly urbanized with a large amount of impervious area. 22nd Street Tributary begins at Main Street, just north of 22nd Street in Downers Grove. The stream travels to the east passing under such roads as Finley Road, I-355, and twice under Foxworth Boulevard before confluencing with the East Branch DuPage River. 3.3.17.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for 22nd Street Tributary. Discharges for the 10-year, 50-year, and 100-year floods for 22nd Street Tributary were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. Frequency-discharge data for the 22nd Street Tributary were developed through the use of the SCS Urban Hydrology for Small Watersheds, Technical Release No. 55 (U.S. Department of Agriculture, 1975). This method was considered the most appropriate because the drainage areas were small, and the method accounted for the diversity and irregularity of the land use within the basin. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBTS.1.

Table EBTS.1: 22nd Street Tributary Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr 22nd Street Tributary

- at mouth 0.88 235 340 390 605 - at Finley Road 0.49 175 254 291 451



Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface profiles for 22nd Street Tributary were developed using a HEC-2 computer step-backwater model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Profiles were determined for the 10-, 50-, 100-, and 500-year floods. Flood elevations for the 22nd Street Tributary may be raised by debris blockage of bridges or culverts. Starting water-surface elevations 22nd Street Tributary were calculated using the slope/area method. Roughness coefficients for 22nd Street Tributary were estimated by field inspection at the various cross section locations. Refer to EBTS.2 for further information. Table EBTS.2: 22nd Street Tributary Manning’s “n” Values



22nd Street 0.045 - 0.080 0.050 - 0.070 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps.


3.3.17.4 Flood Boundaries To reference the flood boundaries for 22nd Street Tributary, see Map Panels: 0506, 0509, 0604 and 0607. 3.3.17.5 Floodways The floodway along the unnamed tributary north of 22nd Street was computed without consideration of backwater flooding near its mouth. Floodway surcharge elevations along the lower portion of the unnamed stream, therefore, are below rather than above the 100-year flood elevations as determined by backwater flooding. Please reference attached Floodway Data Tables for further information. 3.3.17.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Unnamed Stream North of 22nd Street (EBTS)

EBTS0001 1,298 121 92 4.2 683.2 682.9 682.9 0.01 2

EBTS0002 1,838 132 205 1.9 686.6 686.6 686.7 0.11 2

EBTS0003 2,598 127 176 2.2 689.0 689.0 689.0 0.01 2

EBTS0004 3,199 89 165 2.1 690.8 690.8 690.9 0.11

EBTS0005 3,701 141 173 2.0 692.4 692.4 692.5 0.11 2

EBTS0006 4,250 141 188 1.8 694.7 694.7 694.8 0.11 2

EBTS0007 4,800 73 77 4.5 698.8 698.8 698.9 0.11 2

EBTS0008 5,618 34 92 3.2 704.5 704.5 704.6 0.11


AND INCORPORATED AREAS UNNAMED STREAM NORTH OF 22ND STREET (EBTS)

In feet above confluence with East Branch DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

STR

EAM

NOR

TH O

F 22

ND S

TREE

T (E

BTS)

84P

EBTS

0001

EBTS

0002

EBTS

0003

EBTS

0004

EBTS

0005

EBTS

0006

EBTS

0007

EBTS

0008

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

FINL

EY R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



THE 50-YEAR FLOOD PROFILE ISTO CLOSE TO THE 100-YEAR PROFILE

TO BE SHOWN SEPARATELY

3.3.18 Willoway Brook (EBWI)

3.3.18.1 Tributary Description Willoway Brook, previously known as East Branch Tributary No.5, is a 2879-acre watershed that is tributary to the East Branch DuPage River. The communities that contribute watershed area to Willoway Brook are Wheaton, Glen Ellyn, Lisle and Unincorporated DuPage County. The land use characteristic in the headwaters of Wheaton and Glen Ellyn is largely dense residential and commercial. The central and southern, or downstreammost areas, are classified as less-dense residential and open prairie / forested. Willoway Brook begins in the Danada section of Wheaton, on the north side of Butterfield Road, east of East Loop Road. Willoway Brook flows to the south, passing under Butterfield Road, and entering the Danada Forest Preserve. The brook flows into Rice Lake and must flow over a weir /culvert system to exit the lake. Downstream and to the south of Rice Lake, the stream passes under several roads; Robinwood Lane, North Arboretum Circle, Regency Woods Drive, Edgebrooke Drive and Pebble Creek Drive. The stream’s bearing turns to the east, passing under Leask Lane. On the east side of Leask Lane, Willoway Brook enters the Morton Arboretum Property. There are a few service roads and pedestrian bridges in this area, but the primary hydraulic features are the crossing under Main Route (West Side), Sterling Pond and its outlet, and Lake Marmo and outlet. Once through all these features, Willoway Brook winds its way through further marshes until it encounters the East Branch DuPage River. 3.3.18.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Willoway Brook. Discharges for the 10-year, 50-year, and 100-year floods for Willoway Brook were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table EBWI.1.

Table EBWI.1: Willoway Brook Summary of Discharges Summary of Discharges


Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Willoway Brook

- at mouth 4.95 455 730 870 1,200 3.3.18.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for the streams studied in detail and limited detail, including Willoway Brook, were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). Roughness coefficients for Willoway Brook were estimated by field inspection at the various cross section locations. Refer to Table EBWI.2 for further information. Table EBWI.2: Willoway Brook Manning’s “n” Values



Willoway Brook 0.035 - 0.040 0.060 - 0.080 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study.


All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.3.18.4 Flood Boundaries To reference the flood boundaries for Willoway Brook, see Map Panels: 0505, 0507, 0508, 0509 and 0802. 3.3.18.5 Floodways Please reference attached Floodway Data Tables for further information. 3.3.18.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch Tributary No. 5 (EBWI)

EBWI0001 1,390 678.71 2 2 2 2 2 2

EBWI0002 2,452 681.51 2 2 2 2 2 2

EBWI0003 3,499 686.61 2 2 2 2 2 2

EBWI0004 4,363 689.51 2 2 2 2 2 2

EBWI0005 5,240 691.41 2 2 2 2 2 2

EBWI0006 6,566 124 534 1.6 701.0 701.0 701.1 0.11

EBWI0007 7,105 33 94 9.2 702.6 702.6 702.6 0.01

EBWI0008 8,579 714.21 2 2 2 2 2 2

EBWI0009 9,244 716.71 2 2 2 2 2 2

EBWI0010 9,862 719.01 2 2 2 2 2 2

EBWI0011 10,391 719.71 2 2 2 2 2 2

EBWI0012 12,220 724.21 2 2 2 2 2 2


AND INCORPORATED AREAS EAST BRANCH TRIBUTARY NO. 5 (EBWI)

In feet above confluence with East Branch DuPage River2 Data not available

1

TAB

LE 5

660

665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

705 705

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 5 (E

BWI)

51P

EBW

I000

1

EBW

I000

2

EBW

I000

3

EBW

I000

4

EBW

I000

5

CONF

LUEN

CE W

ITH

EAST

BRA

NCH

DUPA

GE R

IVER

DAM

UNNA

MED

ROA

D

UNNA

MED

ROA

D

DAM

ARBO

RETU

M R

OAD

UNNA

MED

ROA

D

UNNA

MED

ROA

D

LEAS

K LA

NE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



CULVERT

LIM

IT O

F FL

OODI

NG

685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 5 (E

BWI)

52P

EBW

I000

6

EBW

I000

7

EBW

I000

8

EBW

I000

9

EBW

I001

0

EBW

I001

1

PRIV

ATE

ROAD

REGE

NCY

WOO

DS D

RIVE

PRIV

ATE

ROAD

NORT

H AR

BORE

TUM

CIR

CLE

ROBI

NWOO

D LA

NE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F FL

OODW

AY

710

715

720 720

725 725

730 730

735 735

11500 12000 12500 13000 13500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

TRIB

UTAR

Y NO

. 5 (E

BWI)

53P

EBW

I001

2

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR FLOOD PROFILE IS TOO CLOSETO THE 100-YEAR PROFILE TO BE SHOWN SEPARATELY

3.4 Fox River (FR)

3.4.1 Brewster Creek (FRBC)

3.4.1.1 Tributary Description Brewster Creek watershed is tributary to the Fox River. The total DuPage County watershed area for Brewster Creek is 4483 acres. The DuPage County communities contributing to the Brewster Creek watershed area are: Bartlett, Wayne and Unincorporated DuPage County. The headwaters found within DuPage County are the only area of development within the watershed. The central and downstream most portions are virtually untouched in the Pratt Wayne Woods Forest Preserve. Brewster Creek begins in the headwaters of Bartlett but are not in a particularly well-formed state until the waters pass from east to west under Route 59. Brewster Creek continues to the west through Pratt Wayne Woods Forest Preserve. Brewster Creek passes under Munger and Powis Roads while within the Forest Preserve, and exits the Forest Preserve and DuPage County simultaneously. Brewster Creek continues through Kane County and confluences with the Fox River in South Elgin. 3.4.1.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Brewster Creek. Discharges for the 10-year, 50-year, and 100-year floods for Brewster Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses for the streams studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented below in Table FRBC.1.

Table FRBC.1: USGS Stream Gages Used for Hydrologic Analysis of Brewster Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years)


Brewster Creek at Valleyview 05551030 14.00 14 A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table FRBC.2.

Table FRBC.2: Brewster Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Brewster Creek

- at river mile 4.16 2.90 94 111 119 393

3.4.1.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for the streams studied in detail and limited detail, including Brewster Creek, were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). Roughness coefficients for Brewster Creek were estimated by field inspection at the various cross section locations. Refer to table FRBC.3 for further details. Table FRBC.3: Brewster Creek Manning’s “n” Values




Brewster Creek 0.035 0.060 - 0.070 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.4.1.4 Flood Boundaries To reference the flood boundaries for Brewster Creek, see Map Panels: 0101, 0102, 0104 and 0105. 3.4.1.5 Floodways Please reference attached Floodway Data Tables for further information. 3.4.1.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Brewster Creek (FRBC)FRBC0001 23,490 520 5,063 0.1 773.8 773.8 773.8 0.01

FRBC0002 24,880 150 1,316 0.2 773.8 773.8 773.8 0.01

FRBC0003 29,835 81 230 1.9 785.8 785.8 785.9 0.11


AND INCORPORATED AREAS BREWSTER CREEK (FRBC)


TAB

LE 5

750

755

760 760

765 765

770 770

775 775

780 780

785 785

790 790

795 795

21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000 26500 27000 27500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WEST BRANCH DU PAGE RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BREW

STER

CRE

EK (F

RBC)

85P

FRBC

0001

FRBC

0002

LIM

IT O

F DE

TAIL

ED S

TUDY

MUN

GER

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


765

770

775 775

780 780

785 785

790 790

27500 28000 28500 29000 29500 30000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BREW

STER

CRE

EK (F

RBC)

86P

FRBC

0003

STAT

E RO

UTE

59HI

GH L

EVEL

BRI

DGE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.4.2 Indian Creek (FRIC)

3.4.2.1 Tributary Description Indian Creek is tributary to the Fox River. Within the bounds of DuPage County, the total Indian Creek watershed area is 3303 acres. The DuPage County communities that contribute watershed area to Indian Creek are Aurora and Unincorporated DuPage County. The land use on Indian Creek in DuPage County is presently under rapid development for residential subdivisions and commercial enterprises. Indian Creek is a rather large watershed that has its headwater regions in DuPage County. Indian Creek itself begins on the upstream side of Bilter Road. Indian Creek passes under Bilter, flows to the west and exits DuPage County before crossing I-88. The other branches to Indian Creek are found in various locations. Two branches exit to the southwest from the Fermilab property. Two other branches drain the southern section of the watershed through older residential subdivisions. A final branch follows the south side ditch of I-88 until confluencing with the Main Stem in Kane County. None of these branches within DuPage County, outside of the Main Stem, have been analyzed or modeled. 3.4.2.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Indian Creek. The hydrologic modeling for Indian Creek was completed using the SCS computer program for project formulation (SCS, Technical Release No. 20, May 1965), a hydrologic model that simulates flood stages and discharges. The stages and discharges are related to watershed characteristics such as drainage area, hydrologic soil group, land use and cover, time of concentration, and channel and floodplain hydraulic characteristics. Given those characteristics and the rainfall amounts, the model will develop hydrographs for local drainage areas and perform a specified series of channel and reservoir routings, as well as hydrograph additions. The result is peak discharges, hydrograph shape, and runoff volumes at specified locations throughout the watershed. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table FRIC.1.

Table FRIC.1: Indian Creek Summary of Discharges


Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Indian Creek

- at mouth 16.10 1,560 2,030 2,250 2,840 - at I-88 4.90 700 925 1,040 1,380

3.4.2.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for Indian Creek were established based on the physical characteristics of the channel including channel size and shape, floodplain size and shape, bridge sizes and shapes, and estimates of Manning’s roughness coefficients. The hydraulic computations were made using the SCS WSP-2 hydraulic model (SCS, Technical Release No. 61, May 1976). This model employs the standard step method for backwater profiles, which is a procedure that estimates total energy at each stream cross section accounting for friction losses between sections. The Bureau of Public Roads method was used to account for the bridge effects on stream hydraulics. The bridge method, which is included in WSP-2, was formulated using the principle of the conservation of energy. Roughness coefficients for Indian Creek were estimated by field inspection at the various cross section locations. Refer to Table FRIC.2 for further details. Table FRIC.2: Indian Creek Manning’s “n” Values



Indian Creek 0.040 - 0.055 0.060 - 0.120


The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.4.2.4 Flood Boundaries To reference the flood boundaries for Indian Creek, see Map Panels: 0404, 0407, 0701 and 0704. 3.4.2.5 Floodways No floodway information is currently available. 3.4.2.6 Flood Profiles No flood profiles are currently available.


3.4.3 Norton Creek (FRNC)

3.4.3.1 Tributary Description Norton Creek is tributary to the Fox River. In DuPage County, 4195 acres are contributed by the communities of Wayne, Bartlett, St. Charles, West Chicago and Unincorporated DuPage County towards Norton Creek. The land use in Norton Creek is similar to that witnessed in Brewster Creek, with the exception that a larger amount of open space is agricultural in use and is slowly becoming developed. There are four branches of Norton Creek in DuPage County. The first branch is the most northern of the branches. Branch one begins north of Army Trail Road, east of Munger Road. The stream passes under Munger Road and continues on a westerly course through the Pratt Wayne Woods Forest Preserve. Branch one turns the southwest, crosses the Illinois Prairie Path, exits the forest preserve, enters the Village of Wayne, crosses the Chicago and Northwestern Railroad, Rochefort Lane, Army Trail Road, Honey Hill Drive and exits DuPage County. Branch one intersects with the remaining Norton Creek branches within Kane County. The second branch begins on the south side of Army Trail Road, east of Munger and somewhat adjacent to Ridge Lane. Branch two travels to the west, passing under Munger Road, and enters the Pratt Wayne Woods Forest Preserve. While in the forest preserve, Branch two takes a long serpentine course, passing under the Illinois Prairie Path. The branch continues out of the forest preserve on a northwest bearing, entering the Village of Wayne. Branch two takes a western bearing, passes under Powis Road and the Chicago and Northwestern Railroad and joins Branch three. The joined branches continue west, passing under Honey Hill Drive and out of DuPage County. The third branch drains the southeastern section of Norton Creek. Branch three begins in an unincorporated subdivision north of North Avenue. The branch travels to the west, exiting the subdivision and entering the Pratt Wayne Woods Forest Preserve. The branch moves to the northwest, exits the forest preserve, crosses Powis Road and intersects with branch four. Branch three travels north where it intersects branch two. Branch four drains the southwestern part of Norton Creek. The branch begins on the north side of North Avenue, west of Powis Road, and travels north. The branch passes under Smith Road and intersects branch three on the downstream side. 3.4.3.2 Hydrologic Analysis


Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Norton Creek. Discharges for the 10-year, 50-year, and 100-year floods for Norton Creek Tributary were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses for the streams studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented below in Table FRNC.1.

Table FRNC.1: USGS Stream Gages Used for Hydrologic Analysis of Norton Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Norton Creek at Wayne 05551050 7.35 15 There are no stream flow recording gages on Norton Creek. In order to simulate flows for Norton Creek and Norton Creek Tributary, a regional frequency analysis has been completed for the gages in the vicinity of the Norton Creek drainage basin. Thirteen USGS gages with one to 20 years of records in the DuPage River drainage basin provided data for the regional frequency analysis. To enable the regional frequency model to more accurately predict the flows for a small basin, the DuPage data have been augmented by records from gages with small drainage areas. Also included in the study are six gages from DuPage County basin having drainage areas of less than 20.0 square miles and six gages from basins within the region having drainage areas less than 2.0 square miles. The technique for a regional frequency analysis outlined in Bulletin No. 17 from the U.S. Water Resources Council (U.S. Water Resources Council, 1976) has been used to calculate the discharges for Norton Creek and Norton Creek Tributary. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table FRNC.2.

Table FRNC.2: Norton Creek Summary of Discharges Summary of Discharges


Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr Norton Creek

- at Dunham Road 4.82 438 665 771 1,038 - u/s of confluence of Norton Creek Tributary 3.46 365 555 645 870 Norton Creek Tributary

- at mouth 1.78 365 555 645 870 3.4.3.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Cross sections for the backwater analyses of Norton Creek and Norton Creek Tributary were determined from field surveys with some overbank cross sections being determined from topographic maps at a scale of 1:4,800, with a contour interval of four feet (U.S. Department of the Interior, 1972). Cross-section locations were at close intervals above and below bridges, dams, and culverts in order to compute the significant backwater effects of these structures. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Water-surface elevations of floods of the selected recurrence intervals on Norton Creek and Norton Creek Tributary were computed through use of the USACE HEC-2 step-backwater computer program (U.S. Army Corps of Engineers, February 1972). This program relates stream geometry, characteristics, and discharge to stream elevation. The starting downstream water-surface elevations for Norton Creek and Norton Creek Tributary used in the HEC-2 step-backwater program were computed by the normal depth methods (USACE, February 1972). Roughness coefficients for Norton Creek and Norton Creek Tributary were determined by field inspection and engineering judgment. Refer to Table FRNC.3 for further information. Table FRNC.3: Norton Creek Manning’s “n” Values




Norton Creek 0.045 - 0.150 0.050 - 0.150 Norton Creek Tributary 0.030 - 0.055 0.045 - 0.055 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.4.3.4 Flood Boundaries To reference the flood boundaries for Norton Creek, see Map Panels: 0101, 0104, 0105, 0107 and 0108. 3.4.3.5 Floodways Please reference attached Floodway Data Tables for further information. 3.4.3.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Norton Creek (FRNC)FRNC0001 20,274 101 384 1.7 741.5 741.5 741.6 0.11

FRNC0002 21,651 221 598 1.1 741.8 741.8 741.9 0.11

FRNC0003 22,778 362 802 0.8 742.1 742.1 742.2 0.11

FRNC0004 24,100 176 160 4.0 742.6 742.6 742.7 0.11

FRNC0005 26,087 283 665 1.0 745.3 745.3 745.4 0.11


AND INCORPORATED AREAS NORTON CREEK (FRNC)

In feet above confluence with Fox River1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Norton Creek Tributary (FRNC)

FRNC0006 1,005 301 959 0.4 741.4 741.4 741.5 0.11 2

FRNC0007 1,936 87 335 1.1 743.0 743.0 743.1 0.11

FRNC0008 3,200 186 315 1.1 743.2 743.2 743.3 0.11

FRNC0009 4,245 209 510 0.7 744.3 744.3 744.4 0.11

FRNC0010 4,575 12 53 6.8 744.8 744.8 744.9 0.11

FRNC0011 5,922 95 279 1.3 746.1 746.1 746.2 0.11

FRNC0012 7,779 289 705 0.5 747.0 747.0 747.0 0.01 3


AND INCORPORATED AREAS NORTON CREEK TRIBUTARY (FRNC)

In feet above confluence with Norton Creek2 Elevation computed without consideration of backwater effects from Norton Creek


1

TAB

LE 5

720

725

730 730

735 735

740 740

745 745

750 750

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

NORT

ON C

REEK

(FRN

C)

87P

FRNC

0001

FRNC

0002

FRNC

0003

FRNC

0004

FRNC

0005

COUN

TY B

OUND

ARY

HONE

Y HI

LL D

RIVE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


720

725

730 730

735 735

740 740

745 745

750 750

755 755

0 1000 2000 3000 4000 5000 6000 7000 8000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

NORT

ON C

REEK

TRI

BUTA

RY (F

RNC)

88P

FRNC

0006

FRNC

0007

FRNC

0008

FRNC

0009

FRNC

0010

FRNC

0011

FRNC

0012

COUN

TY B

OUND

ARY

HONE

Y HI

LL R

OAD

ARM

Y TR

AIL

ROAD

BILL

Y BU

RNS

ROAD

RAIL

ROAD

POW

IS R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.4.4 Waubansee Creek (FRWA)

3.4.4.1 Tributary Description Waubansee Creek is tributary to the Fox River. The total watershed area for Waubansee Creek within the bounds of DuPage County is 5991 acres. The communities contributing watershed area are Aurora, Naperville and Unincorporated DuPage County. The land use characteristics of Waubansee Creek watershed, within the confines of DuPage County, are residential and commercial areas throughout. Waubansee Creek starts on the east side of Eola Road. The creek flows to the southwest, under Eola Road and through the center of a large subdivision. Waubansee Creek then exits DuPage County. Another branch of Waubansee Creek begins south of the Waubansee Main Stem. The area where the branch is found is within a highly dense residential area. Most of this branch, south of Montgomery Road, is in conduit and it passes into Kane County in this state. 3.4.4.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Waubansee Creek. Discharges for the 10-year, 50-year, and 100-year floods for Waubansee Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. For Waubansee Creek, estimates of the 10-, 50-, and 100-year floods were plotted on log-normal probability paper, and the 500-year flood discharges were estimated by straight line extrapolation. The 500-year flood discharge is less reliable than the others because the average period of record for stream gages used to prepare the regional equations is approximately 30 years. The reliability of the 100-year flood discharge is between those of the 50- and 500-year floods. The 100-year discharge value that was used in the 1978 FIS for Waubansee Creek was adopted for the May 15, 1986, restudy. The analysis did not include the 10-, 50-, or 500-year frequency flood events. To allow for zone calculations, the 10-year flood elevation was generated by approximate methods.


A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table FRWA.1.

Table FRWA.1: Waubansee Creek Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Waubansee Creek

- at Kane-Kendall County boundary 16.50 770 1,220 1,447 1,950 3.4.4.3 Hydraulic Analysis

Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.

Cross sections for Waubansee Creek were resurveyed to reflect development within the floodplain that had occurred subsequent to the previous FIS. The 100-year water-surface elevation for the restudy of Waubansee Creek was calculated using the USACE HEC-2 step-backwater program (U.S. Department of Agriculture, 1965). Starting water-surface elevations for Waubansee Creek were calculated using the slope/area method.

Roughness coefficients for Waubansee Creek were determined by field inspection and engineering judgment. Refer to Table FRWA.2 for further information. Table FRWA.2: Waubansee Creek Manning’s “n” Values




Waubansee Creek 0.035 - 0.055 0.050 - 0.070

The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps.

3.4.4.4 Flood Boundaries To reference the flood boundaries for Waubansee Creek, see Map Panels: 0702, 0704, 0705, 0707 and 0708. 3.4.4.5 Floodways Please reference attached Floodway Data Tables for further information. 3.4.4.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Waubansee Creek (FRWA)

FRWA0001 50 70 671.2 671.2 671.2 0.01 2 2

FRWA0002 1,507 290 672.1 672.1 672.1 0.01 2 2

FRWA0003 2,856 310 672.4 672.4 672.4 0.01 2 2

FRWA0004 4,153 75 672.6 672.6 672.6 0.01 2 2

FRWA0005 5,507 40 673.1 673.1 673.1 0.01 2 2

FRWA0006 6,407 100 674.0 674.0 674.0 0.01 2 2

FRWA0007 7,103 105 674.9 674.9 674.9 0.01 2 2

FRWA0008 8,157 80 675.9 675.9 675.9 0.01 2 2

FRWA0009 9,407 70 677.4 677.4 677.4 0.01 2 2


AND INCORPORATED AREAS WAUBANSEE CREEK (FRWA)

In feet above county boundary2 Data not available

1

TAB

LE 5

650

655

660 660

665 665

670 670

675 675

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAU

BANS

EE C

REEK

(FRW

A)

89P

FRW

A000

1

FRW

A000

2

FRW

A000

3

FRW

A000

4

FRW

A000

5

FRW

A000

6

COUN

TY B

OUND

ARY

KAUT

Z RO

AD


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

655

660

665 665

670 670

675 675

680 680

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAU

BANS

EE C

REEK

(FRW

A)

90P

FRW

A000

7

FRW

A000

8

FRW

A000

9

EOLA

ROA

D

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

3.5 Salt Creek (SC)

3.5.1 Main Stem (SCSC)

3.5.1.1 Tributary Description The Salt Creek Main Stem has a direct drainage area of 27.6 square miles. Communities that contribute watershed area to the Salt Creek Main Stem, within the bounds of DuPage County, are: Itasca, Wood Dale, Addison, Villa Park, Elmhurst, Lombard, Oakbrook Terrace, Oak Brook, Hinsdale and Unincorporated DuPage County. Salt Creek is greatly regulated in flow by the Busse Lake, found in the Busse Woods Forest Preserve of Cook County. Upon leaving Busse Woods, Salt Creek flows to the south passing under such roads as Arlington Heights Road and Biesterfield Road in Cook County. Salt Creek crosses into DuPage County at Devon Avenue and continues south through the Salt Creek Country Club where the Main Stem confluences with the Devon Avenue Tributary. Salt Creek resumes flow to the south passing through Thorndale Avenue, the Salt Creek Marsh Forest Preserve at the southernmost tip of which where Spring Brook Creek Tributary confluences with the Main Stem. Continuing south, the Main Stem crosses through the Chicago Milwaukee St. Paul & Pacific Railroad embankment, Irving Park Road, the Salt Creek County Forest Preserve, Elizabeth Court, the Oak Meadows Golf Course, and the Eisenhower Expressway (1-290) the downstream side of which Westwood Creek joins the Salt Creek Main Stem. Still bearing south, the Main Stem passes through Addison Community Park, Lake Street, Cricket Creek Forest Preserve, Fullerton Avenue, North Avenue, the Chicago and Northwestern Railroad, St. Charles Road, Kingery Highway (I-83) and Eldridge Park, the upstream side of which is the confluence location of the Main Stem and Sugar Creek Tributary. The Main Stem crosses Butterfield Road, Roosevelt Road and joins Oakbrook Tributary at Oak Brook Mall. Persuing a more serpentine course, the Salt Creek Main Stem crosses Harger Road, the East-West Tollway (I-88), the Oak Brook Golf Club, and joins Ginger Creek at the Butler National Golf Course. The Main Stem continues south through 31st Street and joins Bronswood Tributary at the Fullersburg Forest Preserve. The Main Stem passes through York Road, and Indian Trail Road, just downstream of which Salt Creek exits DuPage County into Cook County. In Lyons, Salt Creek will confluence with the Des Plaines River. 3.5.1.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Salt Creek.


Discharges for the 10-year, 50-year, and 100-year floods for Salt Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses of the Des Plaines River studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented in Table SCSC.1 below: Table SCSC.1: USGS Stream Gages Used for Hydrologic Analysis of Salt Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Salt Creek at

Elmhurst 05531300 90.6 15

Salt Creek at Oak Brook 05531380 100.0 15

Flood frequency curves for Salt Creek were prepared for this study and are based on discharges calculated by the SCS. The SCS has completed a comprehensive flood management study of the Salt Creek watershed as part of the Chicago Metropolitan Area River Basin Plan. That study included detailed watershed modeling utilizing the SCS watershed model TR-20 (U.S. Department of Agriculture, 1974). It is an advanced hydrologic model that accurately simulates the historical flood stage- and discharge-hydrographs. The model was used for a regional analysis of the entire watershed. The model included consideration of the Busse Woods and Kingery Detention Reservoirs. Elevation-capacity and outlet rating data were included in the model and were utilized in routing the hydrographs through the watershed. Estimates of flood discharge resulting from that study are the most current, and the 100-year discharges have been approved by the State of Illinois for use in the state’s floodplain regulation program. Data are located in the Illinois State Water Survey Floodplain Repository. Harza prepared additional hydrologic analyses that provided an independent review of the suitability of the results in concurrence with FIA’s guidelines. Discharges for the 100-, 50-, and 10-year floods were computed for Salt Creek by Harza using regional flood frequency equations for Illinois (Illinois Department of Transportation, 1979). The discharges determined for Salt Creek are higher than the historic discharges because they are based on conditions projected to exist


in the year 2000. The Salt Creek discharges decrease moving downstream as a result of overbank storage. The calculated unit flood discharges were compared to those for neighboring watersheds. This review by Harza established that the flood discharges computed by the SCS using their TR-20 program and certified by the State of Illinois are suitable for use in this FIS. The SCS discharges for the 10-, 25-, and 100-year floods for the two streams were plotted on log-normal probability paper. The 50- and 500-year flood discharges were estimated by straight-line interpolation and extrapolation, respectively.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCSC.2. Table SCSC.2: Salt Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Salt Creek

- at York Road 112 2,158 3,258 3,650 4,427 - at 31st Street 106 2,162 3,258 3,655 4,434 - at confluence with

Ginger Creek 102 2,172 3,277 3,680 4,450 - at confluence with

Oak Brook Tributary 99.2 2,186 3,290 3,696 4,480 - at confluence with

Sugar Creek 95.0 2,187 3,301 3,698 4,495 - at St. Charles Road 90.7 1,911 2,724 3,171 4,520

- at Chicago and NW Railway 88.8 1,915 2,730 3,178 4,530 - at State Route 83 88.0 2,190 3,306 3,701 4,502

- approximately 0.67 mile d/s of I-90 85.7 2,263 3,341 3,846 5,224

- approximately 250 ft d/s of Fullerton Avenue 85.7 2,248 3,308 3,803 5,155 - at Fullerton Avenue 84.0 2,247 3,390 3,803 4,615

- approximately 4,800 ft u/s of Lake Street 82.7 2,267 3,350 3,857 5,240

- approximately 660 ft u/s of Elizabeth Drive 73.0 2,120 3,100 3,524 4,500

- approximately 527 ft d/s of Irving Park Road 71.4 2,110 3,090 3,502 4,490

- approximately 792 ft u/s of Chicago, Milwaukee, St. Paul & Pacific Railroad 70.86 2,110 3,070 3,484 4,470

- upper corporate limit


for City of Wood Dale 54.4 1,650 2,310 2,590 3,260 - at Plum Grove Road 10.18 522 792 913 1,225 3.5.1.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Cross sections for the backwater analyses on Salt Creek were field surveyed by the SCS. Cross-section data for Salt Creek were obtained from Regulation of Construction Within the Floodplain of Lower Salt Creek and Tributaries (Illinois Department of Transportation, 1980). Sections were located at close intervals above and below bridges and culverts in order to compute the significant backwater effects of these structures. Starting water-surface elevations for Salt Creek were developed by the slope/area method. Channel roughness factors for Salt Creek were assigned on the basis of field inspection of floodplain areas and from previous studies by the SCS. Refer to Table SCSC.3 for further details.


Table SCSC.3: Salt Creek Manning’s “n” Values



- Salt Creek 0.020 - 0.070 0.020 - 0.300 3.5.1.4 Flood Boundaries To reference the flood boundaries for Salt Creek, see Map Panels: 0301, 0302, 0304, 0305, 0307, 0308, 0309, 0601, 0602, 0603, 0605, 0606, 0609 and 0903. 3.5.1.5 Floodways Floodway widths for Salt Creek were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. For Salt Creek, because the mapped floodway extends outside the mapped 100-year floodplain, the floodway was delineated within the 100-year floodplain using engineering judgment. The floodway for Salt Creek extends beyond the corporate limits for City of Elmhurst. Please reference attached Floodway Data Tables for further information. 3.5.1.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Salt Creek (SCSC)SCSC0001 50,268 158 1,155 3.2 642.5 642.5 642.6 0.11

SCSC0002 54,761 699 2,856 1.7 644.6 644.6 644.8 0.21

SCSC1026 55,284 128 362 9.6 645.5 645.1 645.1 0.01 2

SCSC1027 55,844 206 1,407 2.5 646.9 646.9 646.9 0.01

SCSC1028 58,044 243 1,564 2.2 647.3 647.3 647.3 0.01

SCSC1029 60,244 956 1,749 4.8 647.9 647.9 647.9 0.01

SCSC1030 62,204 150 977 3.5 650.3 650.3 650.4 0.11

SCSC1031 65,044 397 1,343 3.5 653.5 653.5 653.6 0.11

SCSC1033 65,294 407 1,470 3.3 653.8 653.8 653.9 0.11

SCSC1034 68,214 780 3,610 1.8 654.6 654.7 654.8 0.11

SCSC1035 70,454 1,412 4,254 2.0 655.0 655.0 655.1 0.11

SCSC1036 71,094 1,097 5,122 1.3 655.2 655.2 655.3 0.11

SCSC1037 71,337 130 1,142 2.7 655.2 655.2 655.3 0.11

SCSC1039 71,515 125 978 3.5 655.2 655.2 655.3 0.11

SCSC1040 71,890 138 865 4.1 655.4 655.4 655.5 0.11

SCSC1041 72,530 99 864 3.6 656.0 656.0 656.1 0.11

SCSC1042 73,090 129 1,025 3.1 656.3 656.3 656.5 0.11

SCSC1043 73,510 106 1,030 3.0 656.5 656.5 656.7 0.11


AND INCORPORATED AREAS SALT CREEK (SCSC)


3 Width includes floodway of Spring Brook Creek

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSC1047 73,940 136 1,219 2.8 656.8 656.8 656.9 0.11

SCSC1049 74,098 532 3,066 1.9 657.0 657.0 657.1 0.11

SCSC1050 74,208 723 3,165 1.5 657.0 657.0 657.1 0.11

SCSC1051 74,618 332 1,639 2.7 657.1 657.1 657.2 0.11

SCSC1052 75,178 214 1,063 3.8 657.3 657.3 657.4 0.11

SCSC1053 75,489 232 1,167 3.7 657.5 657.5 657.6 0.11

SCSC1054 76,249 443 2,580 2.1 657.9 657.9 658.0 0.11

SCSC1055 76,659 393 1,790 2.0 658.0 658.0 658.1 0.11

SCSC1056 77,059 760 1,544 3.3 658.2 658.2 658.3 0.11

SCSC1057 77,469 673 2,224 2.5 658.5 658.5 658.6 0.11

SCSC1058 77,879 410 2,706 2.2 658.7 658.7 658.8 0.11

SCSC1059 78,299 257 1,644 2.1 658.8 658.8 658.9 0.11

SCSC1060 79,254 170 1,187 3.2 659.4 659.4 659.5 0.11

SCSC1061 79,844 136 1,123 3.2 659.9 659.9 660.0 0.11

SCSC1062 80,134 146 877 4.1 660.2 660.2 660.3 0.11

SCSC1063 80,649 395 1,553 2.8 660.8 660.8 660.9 0.11

SCSC1064 80,989 140 2,276 2.5 661.1 661.1 661.2 0.11





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSC0017 81,250 73 1,298 2.4 662.0 661.5 661.6 0.11

SCSC0018 82,935 130 1,438 2.2 662.5 662.5 662.5 0.01

SCSC0019 83,516 150 1,196 2.6 662.5 662.5 662.5 0.01

SCSC0020 84,219 165 1,308 2.4 662.5 662.5 662.5 0.01

SCSC0021 84,746 170 1,395 2.3 662.5 662.5 662.5 0.01

SCSC0022 85,504 250 1,479 2.6 662.7 662.7 662.7 0.01

SCSC0023 86,520 455 1,768 2.5 663.0 663.0 663.1 0.11

SCSC0024 86,854 410 1,338 3.0 663.2 663.2 663.3 0.11

SCSC0025 87,370 445 1,246 3.0 663.7 663.7 663.8 0.11

SCSC0026 87,988 500 2,629 1.8 664.1 664.1 664.2 0.11

SCSC0027 91,964 130 2,242 1.6 665.9 665.9 666.0 0.11

SCSC0028 92,526 75 1,698 2.3 666.8 666.8 666.8 0.01

SCSC0029 93,878 70 2,346 1.6 667.5 667.5 667.6 0.11

SCSC0030 94,550 120 3,387 1.0 668.0 668.0 668.1 0.11

SCSC0031 96,132 300 1,715 2.1 668.9 668.9 669.0 0.11 2

SCSC0032 97,866 210 1,935 1.8 671.5 671.5 671.6 0.11

SCSC0033 98,400 145 3,178 2.1 672.0 672.0 672.1 0.11





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSC0035 101,350 95 3,319 1.2 672.6 672.6 672.7 0.11

SCSC0036 102,501 387 1,537 2.3 673.1 673.1 673.2 0.11

SCSC0037 103,708 850 6,063 0.6 674.2 674.2 674.3 0.11

SCSC0038 106,683 860 3,568 1.1 674.7 674.7 674.8 0.11

SCSC0039 107,935 903 5,067 0.8 674.8 674.8 674.9 0.11

SCSC0040 111,935 397 8,431 0.4 675.1 675.1 675.2 0.11

SCSC0041 113,364 509 3,516 1.1 675.3 675.3 675.4 0.11

SCSC0042 114,787 494 3,931 1.0 675.5 675.5 675.6 0.11

SCSC0043 117,307 450 5,450 0.7 675.7 675.7 675.8 0.11

SCSC0044 117,986 490 5,738 0.6 675.8 675.8 675.8 0.01

SCSC0045 123,076 900 4,526 0.8 676.7 676.7 676.7 0.01

SCSC0046 125,430 789 4,351 0.8 677.0 677.0 677.1 0.11

SCSC0047 126,804 971 4,744 0.7 677.2 677.2 677.3 0.11

SCSC0048 130,335 429 2,685 1.3 678.2 678.2 678.3 0.11

SCSC0049 131,393 601 4,370 0.8 680.3 680.3 680.4 0.11

SCSC0050 132,433 671 4,503 0.8 680.3 680.3 680.4 0.11

SCSC0051 132,732 671 4,503 0.8 680.3 680.3 680.4 0.11





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSC0055 140,114 357 1,806 1.4 681.6 681.6 681.7 0.11

SCSC0056 140,896 300 2,909 0.9 681.9 681.9 681.9 0.01

SCSC0057 143,669 650 3,676 0.7 682.3 682.3 682.3 0.01





1

TAB

LE 5

620

625

630 630

635 635

640 640

645 645

650 650

47500 48000 48500 49000 49500 50000 50500 51000 51500 52000 52500 53000 53500 54000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

116P

SCSC

0001

COUN

TY B

OUND

ARY

COUN

TY B

OUND

ARY

COUN

TY B

OUND

ARY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


625

630

635 635

640 640

645 645

650 650

54000 54500 55000 55500 56000 56500 57000 57500 58000 58500 59000 59500 60000 60500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

117P

SCSC

0002

SCSC

1026

SCSC

1027

SCSC

1028

SCSC

1029

YORK

ROA

D

FULL

ERSB

URG

DAM


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


630

635

640 640

645 645

650 650

655 655

660

60500 61000 61500 62000 62500 63000 63500 64000 64500 65000 65500 66000 66500 67000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

118P

SCSC

1030

SCSC

1031

SCSC

1033

CONF

LUEN

CE O

F BR

ONSW

OOD

CEM

ETAR

Y TR

IBUT

ARY

31ST

STR

EET

CONF

LUEN

CE O

F GI

NGER

CRE

EK


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


630

635

640 640

645 645

650 650

655 655

660 660

665 665

670 670

67000 67500 68000 68500 69000 69500 70000 70500 71000 71500 72000 72500 73000 73500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

119P

SCSC

1034

SCSC

1035

SCSC

1036

SCSC

1037

SCSC

1039

SCSC

1040

SCSC

1041

SCSC

1042

22ND

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


635

640

645 645

650 650

655 655

660 660

665 665

670 670

675 675

680 680

73500 74000 74500 75000 75500 76000 76500 77000 77500 78000 78500 79000 79500 80000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

120P

SCSC

1043

SCSC

1045

SCSC

1047

SCSC

1049

SCSC

1050

SCSC

1051

SCSC

1052

SCSC

1053

SCSC

1054

SCSC

1055

SCSC

1056

SCSC

1057

SCSC

1058

SCSC

1059

SCSC

1060

SCSC

1061

EAST

WES

T TO

LLW

AY (I

-88)

INTE

RSTA

TE C

ONNE

CTOR

HARG

ER R

OAD

CONF

LUEN

CE O

F SP

RING

ROA

D TR

IBUT

ARY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


635

640

645 645

650 650

655 655

660 660

665 665

80000 80500 81000 81500 82000 82500 83000 83500 84000 84500 85000 85500 86000 86500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

121P

SCSC

1062

SCSC

1063

SCSC

1064

SCSC

1065

SCSC

0017

SCSC

0018

SCSC

0019

SCSC

0020

SCSC

0021

SCSC

0022

ROOS

EVEL

T RO

AD

FRON

TAGE

ROA

D

STAT

E RO

UTE

56 (B

UTTE

RFIE

LD R

OAD)


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


640

645

650 650

655 655

660 660

665 665

670 670

675 675

86500 87000 87500 88000 88500 89000 89500 90000 90500 91000 91500 92000 92500 93000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

122P

SCSC

0023

SCSC

0024

SCSC

0025

SCSC

0026

SCSC

0027

SCSC

0028

CONF

LUEN

CE O

F SU

GAR

CREE

K

ILLI

NOIS

PRA

IRIE

PAT

H

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


645

650

655 655

660 660

665 665

670 670

675 675

680 680

685

93000 93500 94000 94500 95000 95500 96000 96500 97000 97500 98000 98500 99000 99500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

123P

SCSC

0029

SCSC

0030

SCSC

0031

SCSC

0032

SCSC

0033

ST. C

HARL

ES R

OAD

RAIL

ROAD

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


645

650

655 655

660 660

665 665

670 670

675 675

680 680

99500 100000 100500 101000 101500 102000 102500 103000 103500 104000 104500 105000 105500 106000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

124P

SCSC

0034

SCSC

0035

SCSC

0036

SCSC

0037

STAT

E RO

UTE

64 (N

ORTH

AVE

NUE)


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


KINGERY DIKE (SOUTH) TOP ELEVATION

645

650

655 655

660 660

665 665

670 670

675 675

680 680

106000 106500 107000 107500 108000 108500 109000 109500 110000 110500 111000 111500 112000 112500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

125P

SCSC

0038

SCSC

0039

SCSC

0040

KINGERY DIKE (SOUTH)

FULL

ERTO

N AV

ENUE

KINGERY DIKE (NORTH)

LAKE

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


TOP ELEVATION

TOP ELEVATION

650

655

660 660

665 665

670 670

675 675

680 680

112500 113000 113500 114000 114500 115000 115500 116000 116500 117000 117500 118000 118500 119000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

126P

SCSC

0041

SCSC

0042

SCSC

0043

SCSC

0044

CONF

LUEN

CE O

F W

ESTW

OOD

CREE

K

INTE

RSTA

TE 2

90

COUN

TRY

CLUB

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


A POINT APPROXIMATELY 1,300 FEET DOWNSTREAMOF ELIZABETH ROAD

*DATA NOT AVAILABLE UPSTREAM OF SCSC0043 TO

650

655

660 660

665 665

670 670

675 675

680 680

685 685

119000 119500 120000 120500 121000 121500 122000 122500 123000 123500 124000 124500 125000 125500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

127P

SCSC

0045

SCSC

0046

COUN

TRY

CLUB

ROA

D

ELIZ

ABET

H DR

IVE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE UPSTREAM OF SCSC0043 TO A POINT APPROXIMATELY 1,300 FEET DOWNSTREAMOF ELIZABETH ROAD

655

660

665 665

670 670

675 675

680 680

685 685

690 690

125500 126000 126500 127000 127500 128000 128500 129000 129500 130000 130500 131000 131500 132000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

128P

SCSC

0047

SCSC

0048

SCSC

0049

(STA

TE R

OUTE

19)

IRVI

NG P

ARK

BOUL

EVAR

D

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


655

660

665 665

670 670

675 675

680 680

685 685

132000 132500 133000 133500 134000 134500 135000 135500 136000 136500 137000 137500 138000 138500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

129P

SCSC

0050

SCSC

0051

CONF

LUEN

CE O

F SP

RING

BRO

OK C

REEK


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE UPSTREAMOF 200 FEET UPSTREAM OF SCSC0054

660

665

670 670

675 675

680 680

685 685

138500 139000 139500 140000 140500 141000 141500 142000 142500 143000 143500 144000 144500 145000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SALT

CRE

EK (S

CSC)

130P

SCSC

0055

SCSC

0056

SCSC

0057

THOR

NDAL

E AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY

COUN

TY B

OUND

ARY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE UPSTREAMOF 200 FEET UPSTREAM OF SCSC0054

3.5.2 Bronswood Tributary (SCBW)

3.5.2.1 Tributary Description Bronswood Tributary is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Bronswood Tributary Watershed covers approximately 3.25 square miles (2075 acres). This watershed includes parts of the Villages of Oak Brook, Hinsdale, Westmont, and Clarendon Hills, and areas in unincorporated York and Downers Grove North Townships. Bronswood Tributary flows into the main channel of Salt Creek 2,060 feet downstream of 31st Street, and 6,300 feet upstream of the Fullersburg Dam.

The South Branch of Bronswood Tributary (reach #1) begins at a detention pond located within the Illinois Department of Transportation Route 83/Ogden Avenue northwestern cloverleaf. The reach proceeds east under Route 83 into the northeastern cloverleaf, and then exits to the northeast under the northbound Route 83 on-ramp. The stream then continues to wind its way east through thick grasses passing through an old culvert and a private drive until it reaches the confluence with reach #3. The South Branch passes through two weirs and the Adams road culvert before turning to the north to open into a large wetland zone spanning 1900 lineal feet. It is at this point that the South Branch enters the Bronswood Cemetery, flowing in a northerly direction through two ponds and several weirs and bridges. Once free of the cemetery, the reach proceeds on a rapid decent towards the confluence with the North Branch (reach #2), some 3000 lineal feet in total relative distance. The stream then proceeds to the northeast for an additional 130 feet, passing under Spring Road, to join Salt Creek.

Reach #3 is a small tributary draining 0.57 sq. miles (365 acres) of the southeastern-most sections of the Bronswood watershed. The reach originates on the south side of Ogden Avenue, approximately 700 feet east of Route 83. Reach #3, 716 ft in length, flows north under Ogden Avenue, a religious center, and a parking lot before joining the South Branch (reach #1).

The North Branch of Bronswood Tributary (reach #2) begins at Lake Charles in incorporated Westmost, just west of the Pasquinelli Drive corporate areas. After flowing through a 42” and a 48” storm sewer, the stream daylights into a detention basin. The reach passes under Pasquinelli Drive into another detention basin before flowing east under Route 83. On the east side of Route 83, the North Branch expands out to form a shallow ponding area while reorienting the direction of flow to the north. Downstream of the weir forming the pond, the channel flows through some small, unnamed bridges and weirs and eventually merges


with Bronswood reach #4. After this confluence, the North Branch flows freely towards culverts at a private drive, 35th Street and Adams Street before joining the South Branch 130 ft upstream of the confluence with mainstem Salt Creek.

Reach #4 of Bronswood Tributary is 1800 ft in length, draining 0.45 sq. miles (28.8 acres) of watershed. The stream starts in the ditch line on the west side of Route 83 approximately 800 ft north of Oakmont Lane. The channel then proceeds easterly through a 24”culvert passing under Route 83. The stream continues to wind to the southeast where it converges with the North Branch.

The 0.94 sq. miles (~600 acres) directly adjacent to the Bronswood reaches are primarily found in heavily vegetated, undisturbed areas, with the exception of the very headwaters that are a combination of residential and commercial land uses. The land use for the remaining 2.31 sq. miles (~1475 acres), or 71% of the total watershed area, is residential with an interspersing of light commercial.

3.5.2.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Bronswood Creek.. Peak flows for the 10-, 50-, 100-, and 500-year floods were determined for Bronswood Tributary by the ISWS in accordance with the USGS report Technique for Estimating Magnitude and Frequency of Floods in Illinois (U.S. Department of the Interior, 1977). This report described a technique for estimating flood magnitudes at recurrence intervals ranging from 2 to 500 years, for unregulated rural streams in Illinois, having drainage areas ranging from 0.002 to 10,000 square miles. The independent variables, drainage area, slope, rainfall intensity, and an aerial factor were used to define the flood-frequency relationship. In addition, a provision included allowed for weighting the estimate to an existing gage record. The discharges used in this study were determined by the SCS and the ISWS and were approved by the DOWR. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCBW.1. Table SCBW.1: Bronswood Tributary Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr


Bronswood Tributary - at confluence with

Salt Creek 1.25 298 408 448 526 - east of Adams Road 0.95 255 350 384 451 - east of State Route 83 0.31 148 203 223 262 3.5.2.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross-section data for the backwater analyses of Bronswood Tributary, Ginger Creek, and Spring Road Tributary were obtained by field surveys during October 1977. At this time, the ISWS crew conducting the field work also obtained elevation data and structural geometry for the bridges on each creek.

Water-surface elevations on Bronswood Tributary, for all designated recurrence intervals, were computed through use of the USACE HEC-2 step-backwater computer program (USACE, 1976). Elevations for the approximate flooding areas were determined by field inspection. The 100-year flood elevations and resulting floodplains, floodways, and profiles were computed by the ISWS and reported in a January 1980 flood study of Salt Creek and its tributaries (Illinois Department of Transportation, 1980).

Starting water-surface elevations for Bronswood Tributary were taken from the Salt Creek profiles for the corresponding recurrence intervals.

Channel roughness factors (Manning’s “n”) used in the hydraulic computations of Bronswood Tributary were selected by engineering judgment and from field observations of the stream and floodplain areas. The factors were chosen to be consistent with commonly reported values (Dougherty, R. L, 1977; Chow, V. T., 1964; Chow, V. T., 1959). Please refer to Table SCBW.2 for more details. Table SCBW.2: Bronswood Tributary Manning’s “n” Values



- Bronswood Tributary 0.015 - 0.080 0.040 - 0.200


3.5.2.4 Flood Boundaries To reference the flood boundaries for Bronswood Tributary, see Map Panels: 0608, 0609, 0902 and 0903. 3.5.2.5 Floodways Please reference attached Floodway Data Tables for further information. 3.5.2.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Bronswood Cemetery Tributary (SCBW)

SCBW0001 30 137 431 1.0 652.0 651.7 651.8 0.11 2

SCBW0002 910 65 87 5.2 658.5 658.5 658.5 0.01

SCBW0003 1,690 46 112 4.0 667.2 667.2 667.3 0.11

SCBW0004 1,970 80 99 4.5 669.7 669.7 669.8 0.11

SCBW0005 2,750 38 61 7.3 676.3 676.3 676.3 0.01

SCBW0006 2,890 80 230 2.0 681.9 681.9 681.9 0.01

SCBW0007 3,070 100 383 1.2 684.0 684.0 684.1 0.11

SCBW0008 3,570 128 176 2.6 684.4 684.4 684.5 0.11 2

SCBW0009 4,826 342 1,615 0.3 688.2 688.2 688.3 0.11 2

SCBW0010 5,856 155 584 0.7 688.2 688.2 688.3 0.11

SCBW0011 6,047 350 693 0.6 688.8 688.8 688.9 0.11

SCBW0012 6,276 133 413 0.9 688.9 688.9 689.0 0.11 2

SCBW0013 6,447 118 225 1.7 691.0 691.0 691.1 0.11 2

SCBW0014 7,080 29 35 6.4 691.5 691.5 691.6 0.11

SCBW0015 7,750 154 251 0.9 697.4 697.4 697.5 0.11 2


AND INCORPORATED AREAS BRONSWOOD TRIBUTARY CEMETERY (SCBW)

In feet above confluence with Salt Creek2 Actual floodway width cannot be shown on the FIRM due to redelineation of floodplain

1

TAB

LE 5

635

640

645 645

650 650

655 655

660 660

665 665

670 670

675 675

680 680

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SALT CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BRON

SWOO

D CE

MET

ARY

TRIB

UTAR

Y (S

CBW

)

91P

SCBW

0001

SCBW

0002

SCBW

0003

SCBW

0004

CONF

LUEN

CE W

ITH

SALT

CRE

EK

SPRI

NG R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR PROFILE IS TOO CLOSE

TO BE SHOWN SEPARATELYTO THE 100-YEAR PROFILE

660

665

670 670

675 675

680 680

685 685

690 690

2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BRON

SWOO

D CE

MET

ARY

TRIB

UTAR

Y (S

CBW

)

92P

SCBW

0005

SCBW

0006

SCBW

0007

SCBW

0008

SCBW

0009

NORT

HERN

CEM

ETAR

Y BR

IDGE

MID

DLE

CEM

ETAR

Y BR

IDGE

SOUT

HERN

CEM

ETAR

Y BR

IDGE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR PROFILETO BE SHOWN SEPARATELY

670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

5200 5400 5600 5800 6000 6200 6400 6600 6800 7000 7200 7400 7600 7800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BRON

SWOO

D CE

MET

ARY

TRIB

UTAR

Y (S

CBW

)

93P

SCBW

0010

SCBW

0011

SCBW

0012

SCBW

0013

SCBW

0014

SCBW

0015

DAM

ADAM

S ST

REET

CORP

ORAT

E LI

MIT

S DA

M

PRIV

ATE

DRIV

E

LIM

IT O

F FL

OODW

AYRO

BERT

KIN

GERY

HIG

HWAY

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

STAT

E RO

UTE

83/

CULVERT

3.5.3 Devon Avenue Tributary (SCDA)

3.5.3.1 Tributary Description Devon Avenue Tributary is a 1968-acre watershed that is tributary to Salt Creek in DuPage County. The communities that contribute watershed area, within DuPage County, to Devon Avenue Tributary are Itasca and Unincorporated DuPage County. The watershed characteristics are changing as development expands in the area. Within DuPage County, the primary land use surrounding the watercourse is commercial, with residential sectors in the upper reaches of the watershed. Devon Avenue Tributary begins in a detention area on the west side of I-355, just north of the northwest cloverleaf at the intersection of I-355 and Thorndale Avenue. Flow proceeds to the east, under I-355 and immediately enters a corporate pond. Flow continues to the east passing under Park Boulevard, entering a series of linked corporate ponds just behind the Wyndham Resort Hotel. The stream passes through each pond’s weir structure, flows under Pierce Road and changes bearing to the northeast. On the south side of Devon Avenue, the stream runs a parallel route through ditches and corporate ponds. Devon Avenue Tributary passes underneath Arlington Heights Road and smaller crossings, always staying on the south side ditch of Devon Avenue. Devon Avenue Tributary enters the Salt Creek Country Club and confluences with Main Stem Salt Creek. 3.5.3.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Devon Avenue Tributary. For Devon Avenue Tributary a gauging station on Salt Creek located about 20 miles downstream of Itasca was one source of data for defining discharge-frequency relationships. This gage has been operated since 1945. Values of the 10-, 50-, and 100-year peak discharges were obtained from a log-Pearson Type III distribution of annual peak flow data (U.S. Water Resources Council Hydrologic Committee, 1976). However, much channel work has been performed on Salt Creek and rapid urbanization of the watershed has occurred during the operation period of the stream gages, especially in the past 10 years. The effect of these changes has not been adequately recorded. Water from large floods has overflowed into a quarry about 10 miles upstream of the gage. Therefore, peak discharge-drainage area relationships were developed from a combination of historic flood data and unit hydrograph rainfall-runoff relationships. Flood routing was done with the “SCS-TR-20 Project Formulation Computer Program” (U.S. Department of Agriculture, 1974). Linear regression analysis was


used to determine the 10-, 50-, and 100-year peak discharges as a function of the drainage area at any given cross section. The 500-year peak discharge was determined by a log-log extrapolation of peak discharges computed for frequencies up to 100 years. The peak discharges obtained were substantiated by regional flood flow equations for northeastern Illinois. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCDA.1. Table SCDA.1: Devon Avenue Tributary Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Devon Avenue Tributary

- at lower corporate limit for the Village of Itasca 1.20 130 200 240 320 - approximately 100 feet u/s of Pierce Road 0.80 105 165 200 270 3.5.3.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross-section data for Devon Avenue Tributary were obtained from field surveys by the Illinois Division of Water Resources supplemented with field surveys by a contractor for the SCS. In some cases, these cross sections were extended using topographic maps with a 2-foot contour interval (Floodplain Topographic Maps, 1973). Water-surface profiles for Devon Avenue Tributary, and Meacham Creek were developed using the SCS “WSP-2 Water-Surface Profile Computer Program” (U.S. Department of Agriculture, 1974). Profiles were determined for the 10-, 50-, 100-, and 500-year floods for all flooding sources.


Starting elevations for Devon Avenue Tributary, and Meacham Creek were taken from previously published data (Des Plaines River Steering Committee, 1975). Valley and channel roughness coefficients for Devon Avenue Tributary were determined from field observations, USGS’ “Water Supply Paper 1849” (U.S. Department of the Interior, 1967), and the SCS’ “Guide for Selecting Roughness Coefficients” (U.S. Department of Agriculture, 1963). Please refer to Table SCDA.2 for further information. Table SCDA.2: Devon Avenue Tributary Manning’s “n” Values



- Devon Ave Tributary 0.045 - 0.065 0.065 - 0.085 3.5.3.4 Flood Boundaries To reference the flood boundaries for Devon Avenue Tributary, see Map Panels: 0203, 0301 and 0302. 3.5.3.5 Floodways Please reference attached Floodway Data Tables for further information. 3.5.3.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Devon Avenue Tributary (SCDA)

SCDA0001 3,800 435 739 0.3 685.5 685.5 685.6 0.11 2

SCDA0002 5,000 228 388 0.5 685.7 685.7 685.8 0.11 2

SCDA0003 5,200 302 180 1.1 687.8 687.8 687.9 0.11 2


AND INCORPORATED AREAS DEVON AVENUE TRIBUTARY (SCDA)

In feet above Salt Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

681

682

683 683

684 684

685 685

686 686

687 687

688 688

689 689

1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE SALT CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

DEVO

N AV

ENUE

TRI

BUTA

RY (S

CDA)

94P

SCDA

0001

SCDA

0002

SCDA

0003

LIM

IT O

F DE

TAIL

ED S

TUDY PIER

CE R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.5.4 Ginger Creek (SCGC)

3.5.4.1 Tributary Description Ginger Creek is a 3430-acre watershed that is tributary to Salt Creek. Communities that contribute watershed area to Ginger Creek are: Oak Brook, Oakbrook Terrace, Westmont, Lombard, Downers Grove, Clarendon Hills and Hinsdale. The overall watershed characteristics are shared between large-parceled residential and open spaces such as golf courses. Ginger Creek begins in a long series of ponds originating north of Oakbrook Road and east of Meyers Road. Going north, the ponds proceed under Baybrook Lane, and opens up into a larger, longer pond. A restrictor at the northern end of the pond alongs Ginger Creek to pass under Baybrook Lane again. Flow proceeds to the east through a golf course, passes under Midwest Road, Regent Drive, Illinois Route 83, and Jorie Boulevard. On the east side of Jorie, Ginger Creek enters the Butler National Golf Course and confluences with Salt Creek. 3.5.4.2 Hydrologic Analysis The DuPage County Department of Development and Environmental Concerns have been working with the Northeastern Illinois Planning Commission (NIPC) to perform the regional hydrologic analysis for various watersheds since early 1980. A continuous hydrologic model, Hydrologic Simulation Program, FORTRAN (HSPF), was used to simulate the hydrologic characteristics of the watershed. HSPF uses a Watershed Data Management (WDM) file for storing input and output data. The current WDM file contains detailed precipitation data, other meteorologic data, recorded stream flow data, and simulated runoff and streamflow throughout DuPage County. Data is available back to 1948. The precipitation, meteorologic, and recorded streamflow data, along with land cover data are used to develop and calibrate the HSPF model to produce the simulated runoff for six land cover types. The land cover areas for each of the six land covers are generated by County's Geographic Information Systems (GIS) for each watershed. The six land cover types are impervious: flat, medium, and steep grass; forestland; and agricultural/cropland. The procedures used for hydrologic analysis are discussed in Application Guide for Hydrologic Modeling in DuPage County using Hydrologic Simulation Program – Fortran (HSPF), (Price, 1996). HSPF simulates continuous hourly runoff from continuous precipitation and meteorologic data. Both surface and subsurface runoff are simulated. Thus, both stormflow and baseflow are simulated.


Hydrologic modeling for the entire East Branch DuPage River watershed including Tributary No. 2 is documented in Hydraulic Evaluation of HSPF Model for East Branch DuPage River Watershed (Price and Chang, 2001). This document describes the development and calibration of an HSPF model used to represent runoff from land covers throughout the East Branch watershed. The calibrated HSPF model generates unit runoff in inches per hour for six typical land covers. The land covers were developed for soil and vegetative conditions typically found in DuPage County. These land covers represent impervious area, flat, medium and steep sloped grassed areas, forest and agricultural land. Land segments in each tributary subbasin are assigned to one of these land covers within the hydraulic model. Within the hydraulic model, the area is associated with the appropriate HSPF runoff.

Hydrologic Calibration HSPF was regionally calibrated to five streamflow gages in the three primary watersheds in DuPage County (Salt Creek, East Branch of the DuPage River, and West Branch of the DuPage River) and then verified using a separate period of record and additional streamflow gates (ten total gages). The model was later applied in two smaller watersheds at the edge of the County, Sawmill Creek and Springbrook #2 to the DuPage River. The calibration and verification are described in "Hydrologic Calibration of HSPF Model for DuPage County" (NIPC, 1994) and in "Meteorologic Database Extension and Hydrologic Calibration and Hydraulic Evaluation of HSPF Model for Sawmill Creek Watershed" (NIPC, 1996). During the regional calibration and verification of the three primary watersheds and application in Sawmill Creek, it was found that a single set of HSPF model parameters (for each of the six land cover types) was applicable throughout each of the watersheds.

During calibration of the HSPF model, only unrouted runoff volumes were compared to annual, monthly, and event streamflow volumes. Thus, the model was not calibrated in terms of matching peak flows or timing of runoff within events. That portion of the hydrologic calibration occurs during the hydraulic modeling of specific watersheds and is termed "hydraulic evaluation". After hydraulic routing, the runoff through the stream network system, a final adjustment of HSPF model parameters can occur to produce appropriate timing of runoff within events.

Relationship between Hydrologic Simulation and Hydraulic Simulation After the HSPF model is calibrated, the simulated runoff is routed through the stream network using a separate hydraulic model called FEQ. The simulated runoff stored in the WDM (HSPF) is with a format that is incompatible with the FEQ. Thus, a utility program called "WDMUTL" is used to export runoff from the WDM into a time series file (TSF) to be


used in the FEQ model. The TSF contains runoff for each of the six land cover types and for each precipitation gage used to generate the runoff.

A number of TSFs are created for various purposes. Most of the files are used in hydraulic calibration and are created for specific portions of the County or for specific watersheds. This type of TSFs use a detail network of long-term or short-term precipitation gages to better define the temporal and spatial distribution of the calibration storm. The other type of TSFs are created for Countywide use in flood plain studies and alternative analysis. They are TSFLONG and TSFBIG. TSFLONG is based on precipitation data from the O'Hare and Wheaton long-term gages from water years 1949 through 1993. Instead of simulating the entire 45 years of record, DuPage County selected 115 discrete storms, which generated significant runoff volumes. The results from TSFLONG are used to perform frequency analysis. TSFBIG contains runoff based on very large precipitation events that have occurred in the Midwest. These events are used to assess performance of the stream system and hydraulic features under very extreme conditions.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCGC.1. Table SCGC.1: Ginger Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Ginger Creek

- d/s of Jorie Boulevard * * * 1,256 * - approximately 250 ft u/s of Gabion Weir * * * 1,275 * - d/s of Route 83 * * * 1,277 * - d/s of Briarwood Lake * * * 1,271 * - u/s of confluence with Briarwood Ditch * * * 742 * - d/s of Regent Drive * * * 708 * - u/s of Regent Drive * * * 695 * - u/s of Sheet Pile Weir * * * 643 * - approximately 300 ft u/s of Sheet Pile Weir * * * 613 * - approximately 300 ft d/s of confluence with Trinity Lakes 2 Tributary * * * 566 * - d/s of Midwest Road * * * 554 * - u/s of Baybrook Lane * * * 405 * - d/s of Meyers Road * * * 341 * - u/s of Baybrook (west) * * * 175 *


Heritage Oaks Tributary - approximately 680 ft u/s of confluence with Ginger Creek * * * 160 * Lombard Tributary - d/s of Royal Drive * * * 475 * - u/s of Royal Drive * * * 475 * May’s Lake Tributary - u/s 31st Street * * * 170 * - approximately 250 ft u/s of 31st Street * * * 167 * Midwest Club Tributary - approximately 450 ft u/s of confluence with Ginger Creek * * * 143 * - approximately 1,000 ft u/s of confluence with Ginger Creek * * * 124 * - approximately 1,500 ft u/s of confluence with Ginger Creek * * * 106 * - approximately 200 feet d/s of 31st Street * * * 75 *


Hydraulic analysis was conducted using the continuous simulation hydraulic analysis software FEQ. Using FEQ, a detailed model of the Tributary No. 2 drainage network was developed. The model simulates flow storage in detention ponds, natural storage areas and floodplains. It also calculates the depth and discharge of flow through open channels, storm sewers and overflow paths.

Overview of FEQ Software Program FEQ, or Full Equations Model, was developed by Dr. Delbert Franz of Linsley, Kraeger Associates, Ltd. (Franz, 2001) FEQ is used to simulate flow in a stream system by solving numerically the equations for unsteady flow in open channels and through control structures. The program separates the flows into three broad classes: stream reaches, dummy reaches, and level-pool reservoirs. These three parts are then combined using different control structures, such as junctions, bridges, culverts, dams, waterfalls, spillways, weirs, side weirs, pumps, and others. FEQ determines the flow and depth throughout the stream system given initial


and boundary conditions. FEQ can also be applied in the simulation of a wide-range of stream configurations, such as loops, lateral-inflow conditions, and special features. The boundary conditions can be values such as the water-surface stage, discharge, or the stage-discharge relationship at a node. Wind stress may also be included in the analysis, as well as the effects of lateral inflows, when given local runoff intensity data.

FEQ model input consists of the following elements:

97. Run Control – specifies the simulation length and model execution options.

98. Branch Description – defines channel stationing, flow line elevations and cross-section locations.

99. Tributary Area – defines drainage area and land cover proportions draining to each branch and reservoir represented in the model.

100. Network Control Input – describes how the system is connected together and specifies the function tables used to represent hydraulic structures.

101. Operation of Control Structures – there are no operable structures in the Tributary No. 2 drainage network.

102. Input Files – files containing time series of external flow inputs to the system.

103. Output Files – files written by FEQ to be used as flow input to another FEQ model.

104. Special Output – text file output of flow and stage at each time step for a set of specific modeled locations.

105. Function Tables – all cross-section and hydraulic structure information is stored in tables, which must be read into the model.

106. Initial Condition – provides information FEQ needs to determine an initial network solution that can be used as a model boundary condition.

3.5.4.4 Flood Boundaries To reference the flood boundaries for Ginger Creek, see Map Panels: 0604, 0605, 0606, 0607, 0608 and 0609.


3.5.4.5 Floodways Please reference attached Floodway Data Tables for further information. 3.5.4.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Ginger Creek (SCGC)SCGC5001 60 655.5 655.5 655.6 0.11 2 2 2

SCGC5003 200 655.5 655.5 655.6 0.11 2 2 2

SCGC5006 1,115 657.0 657.0 657.1 0.11 2 2 2

SCGC5010 2,045 42 212 6.4 658.3 658.3 658.4 0.11

SCGC5011 2,215 30 134 9.8 659.5 659.5 659.6 0.11

SCGC5012 2,550 80 600 2.2 662.2 662.2 662.3 0.11

SCGC5014 2,800 164 1,251 1.1 664.1 664.1 664.2 0.11

SCGC5015 3,040 335 2,581 0.6 664.1 664.1 664.2 0.11

SCGC5017 3,710 163 1,373 1.0 665.4 665.4 665.5 0.11

SCGC5018 3,935 155 1,334 1.0 655.4 655.4 655.5 0.11

SCGC5019 4,280 158 1,294 1.1 655.4 655.4 655.5 0.11

SCGC5020 4,565 120 900 1.4 655.4 655.4 655.5 0.11

SCGC5030 6,375 70 531 1.5 669.7 669.7 669.8 0.11

SCGC5031 6,515 38 237 3.3 669.7 669.7 669.8 0.11

SCGC5032 6,720 147 1,101 0.7 669.7 669.7 669.8 0.11

SCGC5033 6,925 131 842 0.9 669.7 669.7 669.8 0.11

SCGC5035 7,260 60 137 5.3 669.7 669.7 669.8 0.11

SCGC5036 7,450 55 95 7.2 673.2 673.2 673.3 0.11


AND INCORPORATED AREAS GINGER CREEK (SCGC)

In feet above confluence with Salt Creek2 Data not available


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Ginger Creek (SCGC)SCGC5037 7,615 163 923 0.7 673.9 673.9 674.0 0.11 3

SCGC5038 7,775 230 1,502 0.4 673.9 673.9 674.0 0.11

SCGC5039 8,280 33 139 4.3 674.2 674.2 674.3 0.11

SCGC5040 8,610 39 76 7.7 677.3 677.3 677.4 0.11

SCGC5041 8,740 189 624 0.9 678.1 678.1 678.2 0.11

SCGC5049 9,275 105 417 1.4 688.4 688.4 688.5 0.11

SCGC5050 9,840 75 250 2.3 688.4 688.4 688.5 0.11

SCGC5046 10,450 61 137 3.8 690.6 690.6 690.7 0.11

SCGC5067 11,500 80 179 2.7 695.2 695.2 695.3 0.11

SCGC5068 11,825 90 180 2.4 696.5 696.5 696.5 0.01

SCGC5053 12,320 88 385 1.1 699.3 699.3 699.4 0.11

SCGC5047 15,335 114 815 0.2 699.3 699.3 699.4 0.11

SCGC5051 16,290 155 1,268 0.2 699.3 699.3 699.4 0.11

SCGC5045 16,720 165 705 0.4 699.3 699.3 699.4 0.11


AND INCORPORATED AREAS GINGER CREEK (SCGC)

In feet above confluence with Salt Creek2 Data not available


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Briarwood Ditch (SCGC)SCGC5043 370 114 1,059 0.3 669.7 669.7 669.8 0.11 2

SCGC5069 950 21 70 6.4 669.7 669.7 669.8 0.11 2

SCGC5073 1,600 33 124 2.6 672.1 672.1 672.2 0.11


AND INCORPORATED AREAS BRIARWOOD DITCH (SCGC)

In feet above confluence with Ginger Creek2 Elevation based on unsteady flow model

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Heritage Oaks Tributary (SCGC)

SCGC5044 675 493 5,333 0.0 699.3 699.3 699.4 0.11 2


AND INCORPORATED AREAS HERITAGE OAKS TRIBUTARY (SCGC)


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Lombard Tributary (SCGC)

SCGC5054 250 57 247 1.9 699.3 699.3 699.4 0.11 2 2

SCGC5056 590 48 139 3.4 701.0 701.0 701.0 0.11 2


AND INCORPORATED AREAS LOMBARD TRIBUTARY (SCGC)


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Mays Lake Tributary (SCGC)

SCGC5071 1,400 672.01 2 2 2 2 2 2

SCGC5028 1,640 679.51 2 2 2 2 2 2

SCGC5026 1,925 683.41 2 2 2 2 2 2

SCGS5057 2,635 701.21 2 2 2 2 2 2

SCGC5058 2,710 701.51 2 2 2 2 2 2


AND INCORPORATED AREAS MAYS LAKE TRIBUTARY (SCGC)

In feet above confluence with Ginger Creek2 Data not available

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Midwest Club Tributary (SCGC)

SCGC5066 450 44 122 1.1 695.5 695.5 695.6 0.11

SCGC5065 975 22 72 1.7 695.7 695.7 695.8 0.11

SCGC5064 1,475 223 505 0.2 695.8 695.8 695.9 0.11

SCGC5063 1,795 25 67 1.5 695.8 695.8 695.9 0.11

SCGC5062 2,310 38 35 2.1 697.8 697.8 697.9 0.11

SCGC5061 2,905 702.31 2 2 2 2 2 2


AND INCORPORATED AREAS MIDWEST CLUB TRIBUTARY (SCGC)

In feet above confluence with Ginger Creek2 Data not available

1

TAB

LE 5

635

640

645 645

650 650

655 655

660 660

665 665

670 670

675 675

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

GING

ER C

REEK

(SCG

C)

95P

SCGC

5001

SCGC

5003

SCGC

5006

SCGC

5010

SCGC

5011

SCGC

5012

SCGC

5014

SCGC

5015

SCGC

5017

SCGC

5018

SCGC

5019

SCGC

5020

SCGC

5030

CONF

LUEN

CE W

ITH

SALT

CRE

EK

MCD

ONAL

DS S

ERVI

CE R

OAD

STON

E W

EIR

RONA

LD L

ANE

STON

E W

EIR

LAKE

FRE

D

JORI

E BO

ULEV

ARD

GABI

ON W

EIR

GABI

ON W

EIR

ROUT

E 83

BRIA

RWOO

D CE

NTRA

L RO

AD

CONC

RETE

WEI

R

BRIA

RWOO

D DI

TCH


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


CONF

LUEN

CE O

F

*DATA NOT AVAILABLE

MAY

S LA

KE T

RIBU

TARY

CONF

LUEN

CE O

F

655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

GING

ER C

REEK

(SCG

C)

96P

SCGC

5031

SCGC

5032

SCGC

5033

SCGC

5035

SCGC

5036

SCGC

5037

SCGC

5038

SCGC

5039

SCGC

5040

SCGC

5041

SCGC

5049

SCGC

5050

SCGC

5046

SCGC

5067

SCGC

5068

SCGC

5053

REGE

NT D

RIVE

SHEE

T PI

LE W

EIR

GABI

ON W

EIR

MID

WES

T RO

AD

CONF

LUEN

CE O

F M

IDW

EST

CLUB

TRI

BUTA

RY

BAYB

ROOK

LAN

E

CONF

LUEN

CE O

F LO

MBA

RD T

RIBU

TARY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

CULVERT

675

680

685 685

690 690

695 695

700 700

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

GING

ER C

REEK

(SCG

C)

97P

SCGC

5047

SCGC

5051

SCGC

5045

BAYB

ROOK

LAN

E

CONF

LUEN

CE O

F HE

RITA

GE O

AKS

TRIB

UTAR

Y

MYE

RS R

OAD

DROP

BOX

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

690 690

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH GINGER CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

BRIA

RWOO

D DI

TCH

(SCG

C)

98P

SCGC

5043

SCGC

5069

SCGC

5073

CONF

LUEN

CE W

ITH

GING

ER C

REEK

KING

STON

DR


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

675

680

685 685

690 690

695 695

700 700

705

710

715

720

0 200 400 600 800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

HERI

TAGE

OAK

S TR

IBUT

ARY

99P

SCGC

5044

CONF

LUEN

CE W

ITH

GING

ER C

REEK


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

100-YEAR BACKWATER FROM GINGER CREEK

675

680

685 685

690 690

695 695

700 700

705 705

0 200 400 600 800 1000 1200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

LOM

BARD

TRI

BUTA

RY (S

CGC)

100P

SCGC

5054

SCGC

5056

CONF

LUEN

CE W

ITH

GING

ER C

REEK

ROYA

L VA

LE D

RIVE

LIM

IT O

F FL

OODW

AY


50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

0 500 1000 1500 2000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

MAY

S LA

KE T

RIBU

TARY

(SCG

C)

101P

SCGC

5071

SCGC

5028

SCGC

5026

CONF

LUEN

CE W

ITH

GING

ER C

REEK

CONC

RETE

WEI

R

CONC

RETE

WEI

R

CONC

RETE

WEI

R


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


100-YEAR BACKWATER FROM GINGER CREEK

*DATA NOT AVAILABLE

675

680

685 685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

MAY

S LA

KE T

RIBU

TARY

(SCG

C)

102P

SCGC

5057

SCGC

5058

CONC

RETE

WEI

R

OAK

BROO

K RO

AD

LIM

IT O

F FL

OODW

AY

MAY

S LA

KE II

WEI

R

MAY

S LA

KE I

CULV

ERT

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

CULVERT

CULVERT

680

685

690 690

695 695

700 700

705 705

710 710

0 500 1000 1500 2000 2500 3000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

MID

WES

T CL

UB T

RIBU

TARY

(SCG

C)

103P

SCGC

5066

SCGC

5065

SCGC

5064

SCGC

5063

SCGC

5062

SCGC

5061

CONF

LUEN

CE W

ITH

GING

ER C

REEK

OAK

BROO

K RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY

LEGEND500-YEAR FLOOD100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD*

STREAM BED


*DATA NOT AVAILABLE

3.5.5 Oak Brook Tributary (SCOB)

3.5.5.1 Tributary Description Oak Brook Tributary (previously known as Spring Road Tributary) is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Oak Brook Tributary Watershed covers approximately 1.18 square miles (758 acres). This watershed includes parts of the Villages of Oak Brook, Oak Brook Terrace, and areas in unincorporated York Township. Oak Brook Tributary flows into the main channel of Salt Creek 2,650 feet downstream of Roosevelt Road, and 4,020 feet upstream of Harger Road.

Oak Brook Tributary finds its origins at the Luther Avenue detention basin, which drains 18.3 acres of primarily residential headwaters. The basin exits southeast through a 24” pipe connected to Lake Yelenich and a private pond. These shallow ponds are the beginning of a series of linked, west-to-east, man-made ponds that back-up to businesses on the south and to residential properties on the north. The length of the ponds from Lake Yelenich / Private Pond to the culvert at Renaissance Boulevard is approximately 1330 station feet. Once water passes through the Renaissance Boulevard culvert, it is routed through a small open area before entering a southeasterly-directed conduit to pass underneath the Staybridge Suites parking lot. Oak Brook Tributary then opens into a detention area sandwiched between Butterfield Road to the south, Terrace Boulevard to the north and east and Renaissance Boulevard to the west. Water exits this detention facility (given the name of Terrace Blvd. Pond) through an 1877 ft long 36” conduit that crosses Butterfield Road, winds around businesses and parking lots, and ends at a small detention basin west of Midwest Road and south of Butterfield Road. Oak Brook Tributary then proceeds east through a 405 ft long 48” modified conduit under Midwest Road, and daylights in a ditch for 5 ft. The stream continues through a 168 ft long 66” diameter conduit and a 195 ft long 4x7 box conduit that flows under businesses and parking lots, exiting approximately 460 ft upstream of Eisenhower Road. Oak Brook Tributary then flows in an easterly, serpentine manner through culverts at Eisenhower Road, McArthur Drive, Karban Road, and a pedestrian path before opening up to form the Oak Brook Terrace Park District Headquarters pond. At the eastern end of the pond, the channel resumes its course to the northeast passing underneath the Oak Brook Terrace Park District Entrance. Maintaining this northeast course, the Oak Brook Tributary passes through culverts at Hodges Road, Illinois State Route 83, Oak Brook Center (OBC) West Entrance, and OBC Northwest Entrance. Oak Brook Tributary flows over a weir structure and through culverts at OBC Northeast Entrance Drive and Spring Road. The confluence of Oak


Brook tributary and Salt Creek is approximately 280 ft downstream of the Spring Road culvert.

The long and thin watershed that defines Oak Brook Tributary can be best described by its land use characteristics adjacent to the stream itself. Oak Brook Tributary is heavily developed in the downstream reaches. The first 4,800 ft of stream, starting at the confluence of Oak Brook Tributary with Salt Creek, is retail, highly commercial, and has large impervious roadway surfaces. The next 4,400 ft of stream is flanked by older residential developments. The remaining ~5200 ft of stream returns to a business land use with intermittent high density residential.

3.5.5.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Oak Brook Tributary. Peak flows for the 10-, 50-, 100-, and 500-year floods were determined for Oak Brook Tributary by the ISWS in accordance with the USGS report Technique for Estimating Magnitude and Frequency of Floods in Illinois (U.S. Department of the Interior, 1977). This report described a technique for estimating flood magnitudes at recurrence intervals ranging from 2 to 500 years, for unregulated rural streams in Illinois, having drainage areas ranging from 0.002 to 10,000 square miles. The independent variables, drainage area, slope, rainfall intensity, and an aerial factor were used to define the flood-frequency relationship. In addition, a provision included allowed for weighting the estimate to an existing gage record. The discharges used in this study were determined by the SCS and the ISWS and were approved by the DOWR. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCOB.1. Table SCOB.1: Oak Brook Tributary Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Oak Brook Tributary - at mouth 1.25 320 440 481 565 - just u/s of Route 83 0.82 265 365 395 465 3.5.5.3 Hydraulic Analysis


Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross-section data for the backwater analyses of Oak Brook Tributary were obtained by field surveys during October 1977. At this time, the ISWS crew conducting the fieldwork also obtained elevation data and structural geometry for the bridges on each creek. Water-surface elevations on Oak Brook Tributary for all designated recurrence intervals, were computed through use of the USACE HEC-2 step-backwater computer program (USACE, 1976). Elevations for the approximate flooding areas were determined by field inspection. The 100-year flood elevations and resulting floodplains, floodways, and profiles were computed by the ISWS and reported in a January 1980 flood study of Salt Creek and its tributaries (Illinois Department of Transportation, 1980). Starting water-surface elevations for Oak Brook Tributary were taken from the Salt Creek profiles for the corresponding recurrence intervals. Channel roughness factors (Manning’s “n”) used in the hydraulic computations of Oak Brook Tributary were selected by engineering judgment and from field observations of the stream and floodplain areas. The factors were chosen to be consistent with commonly reported values (Dougherty, R. L, 1977; Chow, V. T., 1964; Chow, V. T., 1959). For further information refer to Table SCOB.2. Table SCOB.2: Oak Brook Tributary Manning’s “n” Values



- Oak Brook Tributary 0.025 - 0.050 0.075 3.5.5.4 Flood Boundaries To reference the flood boundaries for Oak Brook Tributary, see Map Panels: 0605 and 0606.


3.5.5.5 Floodways The floodways for Oak Brook Tributary were taken directly from the Illinois Department of Transportation study of Salt Creek (Illinois Department of Transportation, 1980). Please reference attached Floodway Data Tables for further information. 3.5.5.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Spring Road Tributary (SCOB)

SCOB0001 527 285 895 0.5 661.0 661.0 661.1 0.11

SCOB0002 1,276 42 210 2.3 661.1 661.1 661.2 0.11

SCOB0003 2,011 31 128 3.8 662.5 662.5 662.6 0.11

SCOB0004 2,188 28 101 4.8 663.8 663.8 663.9 0.11

SCOB0005 2,888 65 215 2.2 666.7 666.7 666.8 0.11

SCOB0006 3,300 35 132 3.7 668.2 668.2 668.3 0.11

SCOB0007 3,550 149 459 1.0 671.1 671.1 671.1 0.01

SCOB0008 3,852 226 414 1.0 671.2 671.2 671.2 0.01

SCOB0009 4,050 206 410 1.0 671.3 671.3 671.3 0.01

SCOB0010 4,269 159 280 1.4 671.7 671.7 671.7 0.01

SCOB0011 4,537 142 288 1.6 672.8 672.8 672.8 0.01

SCOB0012 4,830 200 455 0.8 672.9 672.9 672.9 0.01

SCOB0013 5,713 15 39 10.1 676.8 676.8 676.8 0.01

SCOB0014 6,716 80 341 1.2 684.6 684.6 684.7 0.11

SCOB0015 7,224 30 124 3.2 685.2 685.2 685.3 0.11

SCOB0016 7,800 190 653 0.6 685.4 685.4 685.5 0.11

SCOB0017 8,353 280 766 0.4 686.2 686.2 686.3 0.11


AND INCORPORATED AREAS SPRING ROAD TRIBUTARY (SCOB)

In feet above confluence with Salt Creek1

TAB

LE 5

645

650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG R

OAD

TRIB

UTAR

Y (S

COB)

104P

SCOB

0001

SCOB

0002

SCOB

0003

SCOB

0004

SCOB

0005

SCOB

0006

SCOB

0007

SCOB

0008

SCOB

0009

SCOB

0010

SCOB

0011

SCOB

0012

SCOB

0013

CONF

LUEN

CE W

ITH

SALT

CRE

EK

SPRI

NG R

OAD

ACCE

SS R

OAD

ACCE

SS R

OAD

STAT

E RO

UTE

83

HODG

ES R

OAD

PARK

ROA

D

KARB

AN R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


665

670

675 675

680 680

685 685

690 690

695 695

700 700

705 705

6500 7000 7500 8000 8500 9000 9500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG R

OAD

TRIB

UTAR

Y (S

COB)

105P

SCOB

0014

SCOB

0015

SCOB

0016

SCOB

0017

MAC

ARTH

UR D

RIVE

EISE

NHOW

ER R

OAD

MID

WES

T RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

3.5.6 Spring Brook Creek (SCSB)

3.5.6.1 Tributary Description Spring Brook is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Spring Brook watershed covers approximately 14.7 square miles (9408 acres). This watershed includes parts of the Villages of Itasca, Bloomingdale, Addison, Roselle, Elk Grove Village and Schaumburg and areas in unincorporated Addison and Bloomingdale Townships. Spring Brook discharges into Salt Creek between Thorndale Avenue and the CMSPP (Metra) Railroad.

The mainstem of Spring Brook begins in the Village of Schaumburg in an industrial park located north of the Elgin-O’Hare Expressway and west of Roselle Road. Spring Brook flows south into the Village of Roselle to the Meacham Grove Forest Preserve northeast of Bloomingdale Road and Lake Street. From there, Spring Brook flows east into Lake Kadijah. From the outlet of Lake Kadijah, Spring Brook flows generally northeast through Itasca and then the Itasca Country Club before discharging into Salt Lake Creek approximately 2000 feet north of the CMSPP railroad.

Spring Brook has two major tributaries and several minor tributaries. The major tributaries are Meacham Creek which joins Spring Brook at Lake Kadijah and Unnamed Tributary No. 1 to Spring Brook which meets Spring Brook in the Meacham Grove Forest Preserve. Meacham Creek flows from north to south parallel to Meacham/Medinah Road. It begins at a detention pond located south of Virginia Drive in Elk Grove Village. It flows south through the wetlands adjacent to the Elgin-O’Hare Expressway and then through a culvert under Medinah Road. South of Thorndale Avenue it flows into the Medinah Country Club where it eventually discharges into Lake Kadijah.

Unnamed Tributary No. 1 to Spring Brook is not very long but it has a large drainage area in the Village of Bloomingdale. It is mostly contained in storm sewers until it becomes an open channel north of Lake Street and east of Rosedale Avenue.

3.5.6.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Spring Brook Creek and Meacham Creek. Peak flows for the 10-, 50-, 100-, and 500-year floods on Spring Brook Creek and the West Branch Tributary Spring Brook Creek were computed using the TR-20 computer program (U.S. Department of Agriculture, 1965) with data furnished by the SCS. Discharges for this study were coordinated with the ISWS and approved by the IDWR.


Discharges for the 10-year, 50-year, and 100-year floods for Meacham Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. For Meacham Creek, a gauging station on Salt Creek located about 20 miles downstream of Itasca was one source of data for defining discharge-frequency relationships. This gage has been operated since 1945. A gauging station on Meacham Creek at Medinah in the northwest part of Itasca was used in defining discharge-frequency relationships. This gage was operated from 1953-1972. Values of the 10-, 50-, and 100-year peak discharges were obtained from a log-Pearson Type III distribution of annual peak flow data (U.S. Water Resources Council Hydrologic Committee, 1976). However, much channel work has been performed on Salt Creek and rapid urbanization of the watershed has occurred during the operation period of the stream gages, especially in the past 10 years. The effect of these changes has not been adequately recorded. Water from large floods has overflowed into a quarry about 10 miles upstream of the gage. Therefore, peak discharge-drainage area relationships were developed from a combination of historic flood data and unit hydrograph rainfall-runoff relationships. Flood routing was done with the “SCS-TR-20 Project Formulation Computer Program” (U.S. Department of Agriculture, 1974). Linear regression analysis was used to determine the 10-, 50-, and 100-year peak discharges as a function of the drainage area at any given cross section. The 500-year peak discharge was determined by a log-log extrapolation of peak discharges computed for frequencies up to 100 years. The peak discharges obtained were substantiated by regional flood flow equations for northeastern Illinois. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCSB.1. Table SCSB.1: Spring Brook Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Spring Brook Creek - approximately 1,716 ft u/s of Route 53 12.0 642 1,040 1,264 1,800 - at mouth 14.4 493 880 1,090 1,650 - at Medinah Road 6.55 518 790 910 1,208


- at Circle Avenue 4.97 408 614 704 926 - at Foster Avenue 2.60 197 296 340 446 Meacham Creek

- at Lake Kadijah 5.10 192 283 325 426 - at Thorndale Avenue 3.60 115 195 235 328 West Branch Tributary to Spring Brook Creek

- at Roselle Road 1.50 124 186 211 275 3.5.6.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross-section data for the backwater analyses of Spring Brook Creek and the West Branch Tributary to Spring Brook Creek were obtained by field surveys during April-May 1979. At that time, the ISWS crew conducting the fieldwork also obtained elevation data and structural geometry for the bridges on each creek. Elevation data for portions of Spring Brook Creek were also provided by the SCS.

Cross-section and bridge data for Meacham Creek were obtained from field surveys by the Illinois Division of Water Resources supplemented with field surveys by a contractor for the SCS. In some cases, these cross sections were extended using topographic maps with a 2-foot contour interval (Floodplain Topographic Maps, 1973).

Flood profiles on Spring Brook Creek and the West Branch Tributary to Spring Brook Creek for the 10-, 50-, 100-, and 500-year floods were computed by the ISWS with the SCS WSP-2 step-backwater program (Wight Consulting Engineers, Inc., 1978); the necessary input information was supplied by SCS and the field surveys by ISWS.

Water-surface profiles for Meacham Creek were developed using the SCS “WSP-2 Water-Surface Profile Computer Program” (U.S. Department of


Agriculture, 1974). Profiles were determined for the 10-, 50-, 100-, and 500-year floods for all flooding sources.

Starting water-surface elevations on Spring Brook Creek for all designated recurrence intervals were determined from downstream profiles of Spring Brook Creek. Starting water-surface elevations for the West Branch Tributary Spring Brook Creek were taken from profiles of the mainstem Spring Brook Creek.

Starting elevations for Meacham Creek were taken from previously published data (Des Plaines River Steering Committee, 1975).

Channel roughness factors (Manning’s “n”) used in the hydraulic computations, for Spring Brook Creek and West Branch Tributary Spring Brook Creek were selected on the basis of field inspection of floodplain areas. The factors were chosen to be consistent with commonly reported values (U.S. Department of Agriculture, 1965; Chow, V. T., 1964; Chow, V. T., 1959). Refer to Table SCSB.2 for further details. Valley and channel roughness coefficients for Meacham Creek were determined from field observations, USGS’ “Water Supply Paper 1849” (U.S. Department of the Interior, 1967), and the SCS’ “Guide for Selecting Roughness Coefficients” (U.S. Department of Agriculture, 1963). Refer to Table SCSB.2 for further details

Table SCSB.2: Spring Brook Creek Manning’s “n” Values Manning’s “n” Values


- Spring Brook Creek 0.035 - 0.070 0.035 - 0.100 - Meacham Creek 0.045 - 0.065 0.065 - 0.085 - West Branch Tributary to Spring Brook Creek 0.040 - 0.050 0.040 - 0.120 3.5.6.4 Flood Boundaries To reference the flood boundaries for Spring Brook Creek, see Map Panels: 0202, 0203, 0205, 0206, 0301, 0302 and 0304. 3.5.6.5 Floodways


Please reference attached Floodway Data Tables for further information. 3.5.6.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Spring Brook Creek (SCSB)

SCSB0001 528 1,265 8,846 0.1 680.6 680.6 680.7 0.11

SCSB0002 1,478 969 4,487 0.3 680.6 680.6 680.7 0.11

SCSB0003 1,795 1,280 4,830 0.2 680.6 680.6 680.7 0.11

SCSB0004 3,590 336 1,360 0.8 681.2 681.2 681.3 0.11

SCSB0005 5,772 123 617 1.9 683.0 683.0 683.1 0.11

SCSB0006 6,372 234 1,400 0.9 683.1 683.1 683.2 0.11

SCSB0007 7,047 155 881 1.4 686.1 686.1 686.2 0.11

SCSB0008 7,531 418 1,505 0.8 686.7 686.7 686.8 0.11

SCSB0009 7,951 327 1,847 0.7 686.8 686.8 686.9 0.11

SCSB0010 10,457 245 1,132 1.1 687.8 687.8 687.9 0.11

SCSB0011 12,929 430 1,801 0.7 688.2 688.2 688.3 0.11

SCSB0012 14,236 540 1,277 1.0 688.9 688.9 689.0 0.11

SCSB0013 16,116 130 2,310 0.6 689.6 689.6 689.7 0.11

SCSB0014 18,338 270 2,397 0.4 703.6 703.6 703.7 0.11

SCSB0015 20,359 185 1,285 0.7 704.3 704.3 704.4 0.11

SCSB0016 23,456 204 654 1.1 704.9 704.9 705.0 0.11 2

SCSB0017 23,719 230 707 1.0 705.5 705.5 705.6 0.11 2


AND INCORPORATED AREAS SPRING BROOK CREEK (SCSB)

In feet above confluence with Salt Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSB0018 24,158 100 508 1.4 706.1 706.1 706.2 0.11 2

SCSB0019 24,358 100 180 4.0 706.4 706.4 706.5 0.11 2

SCSB0020 24,497 155 475 1.5 708.0 708.0 708.1 0.11 2

SCSB0021 24,660 46 185 3.9 708.4 708.4 708.5 0.11

SCSB0022 24,821 270 1,123 0.6 708.8 708.8 708.9 0.11 2

SCSB0023 26,143 29 151 4.7 711.5 711.5 711.6 0.11

SCSB0024 26,268 187 592 1.2 714.2 714.2 714.3 0.11 2

SCSB0025 26,500 363 1,092 0.6 714.3 714.3 714.4 0.11 2

SCSB0026 26,780 125 275 2.5 715.1 715.1 715.2 0.11

SCSB0027 26,968 163 346 2.0 715.5 715.5 715.6 0.11

SCSB0028 27,049 188 759 0.9 716.5 716.5 716.6 0.11 2

SCSB0029 27,376 140 711 1.0 716.6 716.6 716.7 0.11

SCSB0030 27,644 247 880 0.8 716.6 716.6 716.7 0.11

SCSB0031 28,805 105 282 2.4 718.0 718.0 718.1 0.11

SCSB0032 29,716 143 371 1.8 719.4 719.4 719.5 0.11 2

SCSB0033 30,153 296 718 0.6 719.5 719.5 719.6 0.11 2

SCSB0034 30,376 204 643 0.6 719.6 719.6 719.7 0.11 2




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSB0035 30,801 70 185 2.0 720.4 720.4 720.5 0.11

SCSB0036 31,440 348 415 0.8 720.8 720.8 720.9 0.11 2

SCSB0037 32,372 97 140 2.4 723.9 723.9 724.0 0.11 2

SCSB0038 32,647 700 140 2.4 723.9 723.9 724.0 0.11 2

SCSB0039 32,783 100 236 1.4 724.7 724.7 724.8 0.11 2

SCSB0040 33,089 53 123 2.7 726.0 726.0 726.1 0.11 2

SCSB0041 33,322 33 136 2.4 729.3 729.3 729.4 0.11

SCSB0042 33,527 30 86 3.6 729.6 729.6 729.7 0.11

SCSB0043 34,086 71 130 1.9 730.8 730.8 730.9 0.11 2

SCSB0044 35,016 65 107 2.2 734.7 734.7 734.8 0.11 2

SCSB0045 35,455 22 58 4.1 738.0 738.0 738.1 0.11

SCSB0046 35,661 43 140 1.7 742.0 742.0 742.1 0.11

SCSB0047 36,025 40 136 1.8 743.4 743.4 743.5 0.11

SCSB0048 36,226 64 203 1.2 744.5 744.5 744.6 0.11

SCSB0049 36,605 27 91 2.6 745.1 745.1 745.2 0.11

SCSB0050 36,816 63 177 1.4 747.2 747.2 747.3 0.11

SCSB0051 37,365 49 89 2.4 748.4 748.4 748.5 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



SCSB0052 38,075 22 46 4.6 753.3 753.3 753.4 0.11

SCSB0053 39,188 14 58 3.6 761.8 761.8 761.9 0.11

SCSB0054 39,310 24 64 3.1 762.1 762.1 762.2 0.11

SCSB0055 39,634 27 58 3.5 764.3 764.3 764.4 0.11

SCSB0056 40,194 38 84 2.4 766.0 766.0 766.1 0.11

SCSB0057 41,399 66 98 2.3 775.0 775.0 775.1 0.11

SCSB0058 41,849 17 53 3.8 776.3 776.3 776.4 0.11

SCSB0059 42,346 459 2,113 0.1 783.9 783.9 783.9 0.01 2




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


West Branch Tributary to Spring Brook Creek (SCSB)

SCSB0060 688 45 86 3.2 721.3 721.3 721.4 0.11 2

SCSB0061 1,708 180 153 1.8 726.5 726.5 726.6 0.11 2

SCSB0062 2,225 125 103 2.1 729.0 729.0 729.1 0.11 2

SCSB0063 2,759 125 362 0.6 733.2 733.2 733.3 0.11

SCSB0064 3,233 25 48 4.5 736.3 736.3 736.4 0.11

SCSB0065 3,481 15 35 6.1 740.1 740.1 740.2 0.11

SCSB0066 3,607 32 145 1.5 744.6 744.6 744.7 0.11

SCSB0067 3,829 31 70 3.1 745.3 745.3 745.4 0.11

SCSB0068 4,130 33 52 9.9 749.5 749.5 749.6 0.11


AND INCORPORATED AREAS W. BRANCH TRIBUTARY TO SPRING BROOK CREEK (SCSB)

In feet above confluence with Spring Brook Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Meacham Creek (SCSB)SCSB0069 1,880 176 841 0.4 703.7 703.7 703.8 0.11

SCSB0070 3,955 125 255 1.2 704.3 704.3 704.4 0.11

SCSB0071 6,257 25 112 2.5 710.8 710.8 710.9 0.11

SCSB0072 7,043 130 367 0.8 713.9 713.9 714.0 0.11

SCSB0073 7,808 150 437 0.6 715.3 715.3 715.4 0.11

SCSB0074 9,101 1,376 6,125 0.1 715.9 715.9 716.0 0.11

SCSB0075 9,724 1,257 6,413 0.1 715.9 715.9 716.0 0.11

SCSB0076 10,174 293 1,197 0.2 715.9 715.9 716.0 0.11


AND INCORPORATED AREAS MEACHAM CREEK (SCSB)

In feet above confluence with Spring Brook Creek1

TAB

LE 5

640

650

660 660

670 670

680 680

690 690

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

106P

SCSB

0001

SCSB

0002

SCSB

0003

SCSB

0004

SCSB

0005

SCSB

0006

CONF

LUEN

CE W

ITH

SALT

CRE

EK

N. P

ROSP

ECT

AVEN

UE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


650

660

670 670

680 680

690 690

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

107P

SCSB

0007

SCSB

0008

SCSB

0009

SCSB

0010

SCSB

0011

RAIL

ROAD

ROUT

E 19

(IRV

ING

PARK

BLV

D)

MAP

LE A

VENU

E


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


INTE

RSTA

TE 2

90 (N

ORTH

BOUN

D)

INTE

RSTA

TE 2

90 (S

OUTH

BOUN

D)

660

670

680 680

690 690

700 700

710 710

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

108P

SCSB

0012

SCSB

0013

SCSB

0014

LAKE

KAD

IJAH

SPI

LLW

AY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F M

EACH

AM C

REEK

670

680

690 690

700 700

710 710

720 720

19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

109P

SCSB

0015

SCSB

0016

SCSB

0017

SCSB

0018

SCSB

0019

SCSB

0020

SCSB

0021

SCSB

0022

MED

INAH

ROA

D

MED

INAH

-ON-

THE-

LAKE

ROA

D

LAKE

VIEW

DRI

VE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


680

690

700 700

710 710

720 720

730 730

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

110P

SCSB

0023

SCSB

0024

SCSB

0025

SCSB

0026

SCSB

0027

SCSB

0028

SCSB

0029

SCSB

0030

SCSB

0031

SCSB

0032

SCSB

0033

SCSB

0034

SCSB

0035

SCSB

0036

SCSB

0037

CIRC

LE A

VENU

E

GRAV

EL R

OAD

FARM

ROA

D

CONF

LUEN

CE O

F W

EST

BRAN

CH T

RIBU

TARY

TO S

PRIN

G BR

OOK

CREE

K


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


690

700

710 710

720 720

730 730

740 740

750 750

760 760

32500 33000 33500 34000 34500 35000 35500 36000 36500 37000 37500 38000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

111P

SCSB

0038

SCSB

0039

SCSB

0040

SCSB

0041

SCSB

0042

SCSB

0043

SCSB

0044

SCSB

0045

SCSB

0046

SCSB

0047

SCSB

0048

SCSB

0049

SCSB

0050

SCSB

0051

FOST

ER A

VENU

E

PRIV

ATE

DRIV

E

WAL

NUT

STRE

ET

ROSE

LLE

ROAD

TURN

ER A

VENU

E

BRYN

MAW

R AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


730

740

750 750

760 760

770 770

780 780

790 790

800 800

38000 38500 39000 39500 40000 40500 41000 41500 42000 42500 43000 43500 44000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

CRE

EK (S

CSB)

112P

SCSB

0052

SCSB

0053

SCSB

0054

SCSB

0055

SCSB

0056

SCSB

0057

SCSB

0058

SCSB

0059

PINE

AVE

NUE

MAP

LE A

VENU

E

WIL

LOW

STR

EET

ELM

AVE

NUE

HILL

STR

EET

CENT

RAL

AVEN

UE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

CULVERT

710

715

720 720

725 725

730 730

735 735

740 740

745 745

750 750

755 755

0 500 1000 1500 2000 2500 3000 3500 4000 4500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SPRING BROOK CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY T

O SP

RING

BRO

OK C

REEK

(SCS

B)

113P

SCSB

0060

SCSB

0061

SCSB

0062

SCSB

0063

SCSB

0064

SCSB

0065

SCSB

0066

SCSB

0067

SCSB

0068

CONF

LUEN

CE W

ITH

SPRI

NG B

ROOK

CRE

EK

BLOO

MIN

GDAL

E RO

AD

MAP

LE A

VENU

E

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

MEA

CHAM

CRE

EK (S

CSB)

114P

SCSB

0069

SCSB

0070

SCSB

0071

CONF

LUEN

CE W

ITH

SPRI

NG B

ROOK

CRE

EK

LAKE

KAD

IJAH

MED

INAH

MOU

TH

BOUL

EVAR

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


COUN

TRY

CLUB

ROA

D

IRVI

NG P

ARK

690

695

700 700

705 705

710 710

715 715

720 720

725 725

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

MEA

CHAM

CRE

EK (S

CSB)

115P

SCSB

0072

SCSB

0073

SCSB

0074

SCSB

0075

SCSB

0076

RAIL

ROAD

MAP

LE A

VENU

E

THOR

NDAL

E AV

ENUE

MED

INAH

ROA

DLI

MIT

OF

DETA

ILED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.5.7 Sugar Creek (SCSU)

3.5.7.1 Tributary Description Sugar Creek is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Sugar Creek Watershed covers approximately 4.06 square miles (2598 acres). This watershed includes parts of the City of Villa Park, the City of OakBrook Terrace, the Village of Lombard, and unincorporated York Township. Sugar Creek flows into the main channel of Salt Creek at approximately 3,500 feet upstream of Illinois Route 56 (Butterfield Road) and approximately 13,000 feet downstream of Illinois Route 64 (North Avenue).

Tributary Number 4 drains approximately 0.21 square miles of area in the southwestern extent of the Sugar Creek watershed. The channel in this reach consists of segments of roadside drainage ditches and backyard swales contributing to the formation of a short channel segment just upstream of the High Point Center Ponds. The mapped portion of the channel begins just north of 15th Place. The channel flows north through a culvert under an entrance into an apartment complex and continues north for approximately 1000 feet to the confluence with the mainstem channel at High Point Center Ponds. Land use in this reach is predominately residential with some light commercial uses.

Tributary Number 3 drains approximately 0.37 square miles of area in the southern portion of the Sugar Creek watershed. The reach begins at a detention pond within Montini Park located just north of 16th Street. Flowing north from the pond outlet structure, the thick grass channel continues through culverts under 14th Street and 13th Street. Flow is then restricted by a berm constructed in park property just upstream of 13th Street. Water backs up in the open park space on both sides of 13th Street. After passing through the berm culverts, flow continues through a forested reach approaching a culvert under Roosevelt Road. The reach then continues through a thick-grassed channel for approximately 1,180 feet to the confluence with the mainstem channel at Old Grove Ponds. Land use in the reach is primarily residential with inclusions of light commercial and park uses.

Tributary Number 2 drains approximately 0.26 square miles of area in the southeastern extent of the Sugar Creek Watershed. The channel in this reach consists of segments of roadside drainage ditches, storm sewers, and backyard swales contributing to the formation of a channel approximately 1,000 feet upstream of Roosevelt Road at the outfall of a storm sewer segment. The mapped portion of the channel begins approximately 500 feet south of Roosevelt Road. The channel flows north through a dense


grass ditch to the south side of Roosevelt Road. The channel then enters approximately 900 linear feet of closed conduit passing under a commercial shopping center north of Roosevelt Road. Flow leaving the conduit continues through a thick grass channel segment for approximately 600 feet to the confluence with the mainstem channel. Land use in the reach is a combination of commercial and multiple-family residential.

The mainstem channel of Sugar Creek, including contributions from its tributaries, drains a total of 4.06 square miles. A series of roadside ditches and backyard swales drain into a storm sewer segment in the southwestern extent of the watershed. The mainstem channel begins at the outfall of this storm sewer, approximately 500 feet downstream of Highland Avenue. The channel continues east to a pair of 30-inch diameter culverts under Grace Street. The area between Grace Street and Roosevelt Road consists of a pair of ponds connected by a 30-inch diameter culvert that have been modified for flood storage. Tributary No. 4 joins the mainstem channel at the southwestern edge of the western pond. Flow leaves the eastern pond through a 42-inch diameter culvert under Roosevelt Road. Flow continues north in a confined thick grass channel through a commercial area for approximately 150 feet to a 48-inch diameter culvert controlling flow into the on-line ponds upstream of Fairview Avenue. Tributary No. 3 joins the mainstem channel at the southern edge of the series of ponds. Flow continues east for approximately 3,070 linear feet through a thick grass channel that passes through four similar road crossing culverts at Fairview Avenue, Ahrens Avenue, School Street, and Westmore Avenue. Downstream of Westmore Avenue, the channel enters a meandering segment of typically short turf grass channel for approximately 2,420 linear feet through the Willowbrook High School property to Riordan Road. A series of four similar elliptical culverts are located in the channel segment at pedestrian path crossings on the High School property. Tributary No. 2 joins the mainstem channel approximately 580 feet upstream of Riordan Road. The area between Riordan Road and Ardmore Avenue consists of a short grass channel with a broad floodplain. Just upstream of Ardmore Avenue, the channel enters a short, steep segment entering the 12’ x 6’ box culvert crossing the road. The channel continues northeast for approximately 1,045 feet through a confined grass channel to a box culvert crossing at Harrison Street. Flow continues northeast through a concrete lined trapezoidal channel between Harrison Street and Summit Avenue. At Summit Avenue, flow enters a segment of closed conduit from Summit Avenue to Cross Street of approximately 1,080 feet in length. Tributary No. 1 joins the mainstem channel through a storm sewer outlet located at the downstream face of the conduit reach. Flow exits the closed conduit to the east into a short grass channel for approximately 766 feet to the triple-box culvert crossing at Villa Avenue. From Villa Avenue, flow enters the Sugar Creek Golf


Course. Flowing east for 260 feet through short grass at the edge of the property, the channel enters a segment of 1,310 linear feet of sheet pile lined channel that extends one to two feet above the normal water line. The sheet pile lining ends at a weir on the golf course property approximately 600 feet upstream of Illinois Route 83. The channel segment from the weir east to the triple-box culvert crossing Illinois Route 83 consists of a thick grass overbank. From Illinois Route 83, the thick-grassed channel continues east for approximately 310 feet to the triple-box culvert under Riverside Drive. From Riverside Drive, the channel continues east for approximately 650 feet through a steep thick grass approach to the confluence with the main channel of Salt Creek.

3.5.7.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Sugar Creek. Discharges for the 10-year, 50-year, and 100-year floods for Sugar Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. Peak flows for the 10-, 50-, 100-, and 500-year floods on Sugar Creek were computed using the Soil Conservation Service (SCS) “Technical Release No. 20” (U.S. Department of Agriculture, 1965).

Peak flows for the 10-, 50-, 100-, and 500-year floods on Sugar Creek Tributary A were computed by the Illinois State Water Survey in accordance with the USGS report, Technique for Estimating Magnitude and Frequency of Floods in Illinois (U.S. Department of the Interior, 1977). This report describes a technique for estimating flood magnitudes at recurrence intervals ranging from 2 to 500 years, for unregulated rural streams in Illinois, having drainage areas ranging from 0.002 to 10,000 square miles. The independent variables – drainage area, slope, rainfall intensity, and an aerial factor – are used to define the flood frequency relationship. In addition, a provision included allows for weighting the estimate to an existing gage record. The discharges used in this study were coordinated with the Illinois State Water Survey and approved by the Illinois Division of Water Resources. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCSU.1. Table SCSU.1: Sugar Creek Summary of Discharges


Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Sugar Creek - at confluence with Salt Creek 4.10 650 890 966 1,143 - at Villa Avenue 3.65 570 780 850 1,000 - at State Route 83 1.58 400 542 596 700 Sugar Creek Tributary A - at Villa Park Southern corporate limits 0.31 205 265 290 335 3.5.7.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross sections for Sugar Creek were obtained from topographic maps (USDA, SCS, 1975).

Cross-section data for the backwater analysis of Sugar Creek Tributary A were obtained by field surveys during September 1977. At this time, the Illinois State Water Survey crew conducting the fieldwork also obtained elevation data and structural geometry for all bridges on the creek.

Water-surface elevations for Sugar Creek were computed using the USACE HEC-2 step-backwater computer program (USACE, 1991). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Starting water-surface elevations for Sugar Creek were taken from the Salt Creek profiles for the corresponding recurrence intervals. Water-surface elevations on Sugar Creek Tributary A for all designated recurrence intervals were computed through use of the USACE HEC-2 step-backwater computer program (USACE, November 1976). Roughness factors (Manning’s “n”) used in the hydraulic computations for Sugar Creek and Sugar Creek Tributary A were chosen by engineering judgment and were based on field inspections of the streams and


floodplain areas. The factors were chosen to be consistent with commonly reported values (Chow, V. T., 1964; Chow, V. T., 1959). Refer to Table SCSU.2 for further details. Table SCSU.2: Sugar Creek Manning’s “n” Values



- Sugar Creek 0.015 - 0.042 0.055 - 0.065 - Sugar Creek Tributary A 0.020 - 0.042 0.060

3.5.7.4 Flood Boundaries To reference the flood boundaries for Sugar Creek, see Map Panels: 0602, 0604, 0605 and 0606. 3.5.7.5 Floodways

The floodway for Sugar Creek Tributary A was determined using the HUD-15 computer program (U.S. Department of Agriculture, 1977). A portion of the floodway for Salt Creek lies outside the corporate limits of Village of Villa Park. Please reference attached Floodway Data Tables for further information. 3.5.7.6 Flood Profiles Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Sugar Creek (SCSU)SCSU0001 2,659 592 2,482 0.4 665.4 665.4 665.5 0.11

SCSU0002 4,140 315 1,420 0.7 665.5 665.5 665.6 0.11

SCSC0003 4,547 240 944 1.0 665.7 665.7 665.8 0.11

SCSU0004 6,249 63 191 4.5 668.4 668.4 668.5 0.11

SCSU0005 6,964 25 97 8.8 668.9 668.9 669.0 0.11

SCSU0006 8,297 39 111 7.7 679.5 679.5 679.6 0.11

SCSU0007 9,400 152 661 1.3 687.3 687.3 687.4 0.11

SCSU0008 10,002 179 751 0.9 690.6 690.6 690.7 0.11

SCSU0009 10,369 100 454 1.5 690.7 690.7 690.8 0.11

SCSU0010 11,240 125 321 2.2 691.0 691.0 691.1 0.11


AND INCORPORATED AREAS SUGAR CREEK (SCSU)

In feet above confluence with Salt Creek1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Sugar Creek Tributary A (SCSU)

SCSU0011 57 49 157 1.9 688.2 687.9 688.0 0.11 2

SCSU0012 564 51 162 1.8 688.4 688.4 688.5 0.11

SCSU0013 1,677 106 201 1.4 704.4 704.4 704.5 0.11

SCSU0014 1,911 40 106 2.7 704.5 704.5 704.6 0.11


AND INCORPORATED AREAS SUGAR CREEK TRIBUTARY A (SCSU)

In feet above confluence with Sugar Creek2 Elevation computed without consideration of backwater effects from Sugar Creek

1

TAB

LE 5

640

645

650 650

655 655

660 660

665 665

670 670

675

680

685

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SUGA

R CR

EEK

(SCS

U)

131P

SCSU

0001

SCSU

0002

SCSC

0003

SCSU

0004

CONF

LUEN

CE W

ITH

SALT

CRE

EK

RIVE

RSID

E DR

IVE

ROBE

RT K

INGE

RY H

IGHW

AY

FRON

TAGE

ROA

D

S. V

ILLA

AVE

NUE

S. E

UCLI

D AV

ENUE

SUM

MIT

AVE

NUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM SALT CREEK

CULVERTST

ATE

ROUT

E 83

/

650

655

660 660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SUGA

R CR

EEK

(SCS

U)

132P

SCSU

0005

SCSU

0006

SCSU

0007

SCSU

0008

SCSU

0009

SCSU

0010

HARR

ISON

STR

EET

ARDM

ORE

AVEN

UE

RIOR

DON

ROAD

SCHO

OL C

ROSS

ING

SUGA

R CR

EEK

TRIB

UTAR

Y A

SCHO

OL C

ROSS

ING

SCHO

OL C

ROSS

ING

SCHO

OL C

ROSS

ING

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F

670

675

680 680

685 685

690 690

695 695

700 700

705 705

710 710

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SUGAR CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SUGA

R CR

EEK

TRIB

UTAR

Y A

(SCS

U)

133P

SCSU

0011

SCSU

0012

SCSU

0013

SCSU

0014

CONF

LUEN

CE W

ITH

SUGA

R CR

EEK

ROOS

EVEL

T RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

100-YEAR BACKWATERFROM SUGAR CREEK

3.5.8 Westwood Creek (SCWC)

3.5.8.1 Tributary Description Westwood Creek is a 3805-acre watershed that is tributary to Salt Creek. The communities that contribute watershed area to Westwood Creek are Addison, Lombard, Villa Park and Unincorporated DuPage County. The general land use characteristics are residential throughout, with less dense area on the extreme southwest and northwest sections of the watershed. The Westwood South Branch drains the southern portion of the watershed, with the creek origins in the Fullerton Park Forest Preserve. Flow proceeds to the north, passing under Fullerton Avenue, entering an Addison park pond. The South Branch continues to the north, passing under Army Trail Road, entering the Addison Golf Club and merging with the Westwood Creek Main Stem. The Westwood Creek Main Stem drains the northwestern section of the watershed. The uppermost sections of the watershed are residential, with some sections in conduit, but become open channel at the Army Trail Nature center just east of Lombard Avenue and north of Army Trail Road. The Main Stem travels east, crosses Pioneer Drive, Wesley Drive and N. Country Club Drive before entering the Addison Golf Club property. The Main Stem confluences with Westwood Creek South Branch in the golf course, and changes bearing to the northeast. The Main Stem crosses Mill Road, Lake Street, Highview Avenue, Lincoln Avenue, Rozanne Drive and Addison Road before confluencing with Salt Creek 3.5.8.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Westwood Creek. Discharges for the 10-year, 50-year, and 100-year floods for Westwood Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. Flood frequency curves for Salt Creek and Westwood Creek were prepared for this study and are based on discharges calculated by the SCS. The SCS has completed a comprehensive flood management study of the Salt Creek watershed as part of the Chicago Metropolitan Area River Basin Plan. That study included detailed watershed modeling utilizing the SCS watershed model TR-20 (U.S. Department of Agriculture, 1974). It


is an advanced hydrologic model which accurately simulates the historical flood stage- and discharge-hydrographs. The model was used for a regional analysis of the entire watershed. The model included consideration of the Busse Woods and Kingery Detention Reservoirs. Elevation-capacity and outlet rating data were included in the model and were utilized in routing the hydrographs through the watershed. Estimates of flood discharge resulting from that study are the most current, and the 100-year discharges have been approved by the State of Illinois for use in the state’s floodplain regulation program. Data are located in the Illinois State Water Survey Floodplain Repository. Harza prepared additional hydrologic analyses which provided an independent review of the suitability of the results in concurrence with FIA’s guidelines. Discharges for the 100-, 50-, and 10-year floods were computed for Salt Creek and Westwood Creek by Harza using regional flood frequency equations for Illinois (Illinois Department of Transportation, 1979). The discharges determined for Salt Creek are higher than the historic discharges because they are based on conditions projected to exist in the year 2000. The Salt Creek discharges decrease moving downstream as a result of overbank storage. The calculated unit flood discharges were compared to those for neighboring watersheds. This review by Harza established that the flood discharges computed by the SCS using their TR-20 program and certified by the State of Illinois are suitable for use in this FIS. The SCS discharges for the 10-, 25-, and 100-year floods for the two streams were plotted on log-normal probability paper. The 50- and 500-year flood discharges were estimated by straight-line interpolation and extrapolation, respectively. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SCWC.1. Table SCWC.1: Westwood Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Westwood Creek - South Branch - just d/s of Army Trail Road 3.60 68 102 111 220 - just d/s of control structure 3.40 65 99 108 217 - just d/s of Fullerton Avenue 2.60 171 282 323 438 Westwood Creek - - at confluence with


Salt Creek 5.62 371 550 648 860 - approximately 320 ft u/s of Lincoln Street 4.25 239 345 394 570 - at Lake Street 4.22 236 343 389 520 - approximately 200 ft d/s of Country Club 0.66 49 66 74 87 3.5.8.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross sections for the backwater analyses on Westwood Creek were field surveyed by the SCS. Cross-section data for Salt Creek were obtained from Regulation of Construction Within the Floodplain of Lower Salt Creek and Tributaries (Illinois Department of Transportation, 1980). Additional cross sections on the upper portion of Westwood Creek not included in the SCS studies were surveyed by Harza. Sections were located at close intervals above and below bridges and culverts in order to compute the significant backwater effects of these structures.

Water-surface elevations of floods for selected recurrence intervals were computed using hydraulic models for Westwood Creek prepared by the SCS. The models were developed using the SCS WSP-2 backwater program (U.S. Department of the Interior, 1963). The models involve a standard step-backwater computation procedure which estimates total energy at each stream cross section and accounts for friction losses between sections using Manning’s formula. The model requires discharge, stream channel and floodplain geometry, starting water-surface elevation, and roughness data to simulate flood flow conditions.

Starting water-surface elevations for Salt Creek were developed by the slope/area method. Starting elevations for Westwood Creek were determined from the Salt Creek hydraulic model. Channel roughness factors for Westwood Creek were assigned on the basis of field inspection of floodplain areas and from previous studies by the SCS. Further information is available in Table SCWC.2 Table SCWC.2: Westwood Creek Manning’s “n” Values




- Westwood Creek 0.045 - 0.055 0.070 - 0.075 - Westwood Creek South Branch 0.035 - 0.075 0.035 - 0.075 3.5.8.4 Flood Boundaries To reference the flood boundaries for Westwood Creek, see Map Panels: 0206, 0209, 0304, 0305, 0307, 0308 and 0601. 3.5.8.5 Floodways



FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Westwood CreekSCWC0001 225 330 889 0.7 675.7 675.7 675.8 0.11 3

SCWC0002 1,880 342 1,099 0.6 675.9 675.9 676.0 0.11

SCWC0003 2,720 419 1,147 0.6 676.2 676.2 676.3 0.11

SCWC0004 3,830 174 167 2.3 677.0 677.0 677.1 0.11

SCWC0005 4,726 40 459 0.9 679.5 680.5 680.6 0.12 1

SCWC0006 6,380 35 253 1.5 683.9 683.9 684.0 0.11

SCWC0007 7,180 125 268 1.4 684.8 684.8 684.9 0.11

SCWC0008 8,560 110 37 2.0 689.0 689.0 689.1 0.11 3

SCWC0009 10,850 38 38 1.6 692.1 692.1 692.2 0.11 3


AND INCORPORATED AREAS WESTWOOD CREEK

In feet above confluence with Salt Creek2 Data shown are computed based on upstream cross section for conditions at approach to structure


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


South Fork of Westwood Creek (SCWC)

SCWC0010 450 65 87 1.3 685.4 685.4 685.4 0.01

SCWC0011 1,850 545 4,332 0.0 693.3 693.3 693.3 0.01

SCWC0012 3,000 770 1,897 0.1 693.3 693.3 693.3 0.01

SCWC0013 3,368 600 4,852 0.0 693.3 693.3 693.3 0.01

SCWC0014 4,418 740 5,746 0.1 693.3 693.3 693.3 0.01

SCWC0015 5,540 220 754 0.4 693.4 693.4 693.4 0.01


AND INCORPORATED AREAS SOUTH FORK OF WESTWOOD CREEK (SCWC)

In feet above confluence with Westwood Creek1

TAB

LE 5

655

660

665 665

670 670

675 675

680 680

685 685

690 690

695 695

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

TWOO

D CR

EEK

(SCW

C)

134P

SCW

C000

1

SCW

C000

2

SCW

C000

3

SCW

C000

4

SCW

C000

5

SCW

C000

6

SCW

C000

7

SCW

C000

8

SCW

C000

9

CONF

LUEN

CE W

ITH

SALT

CRE

EK

N. A

DDIS

ON R

OAD

ROZA

NNE

DRIV

E

N. L

INCO

LN A

VENU

E

HIGH

VIEW

AVE

NUE

LAKE

STR

EET

MIL

L RO

AD

COUN

TRY

CLUB

DRI

VE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

CULVERT

CULVERT

CULVERT

CULVERT

OF W

ESTW

OOD

CREE

KCO

NFLU

ENCE

OF

SOUT

H FO

RK

670

675

680 680

685 685

690 690

695 695

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WESTWOOD CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SOUT

H FO

RK O

F W

ESTW

OOD

CREE

K (S

CWC)

135P

SCW

C001

0

SCW

C001

1

SCW

C001

2

SCW

C001

3

SCW

C001

4

SCW

C001

5

CONF

LUEN

CE W

ITH

WES

TWOO

D CR

EEK

ARM

Y TR

AIL

ROAD

CONT

ROL

STRU

CTUR

E

FULL

ERTO

N AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

3.6 Sawmill Creek (SW)

3.6.1 Sawmill Creek Main Stem (SWSW)

3.6.1.1 Tributary Description Sawmill Creek is a 6067-acre watershed that is tributary to the Des Plaines River. The communities that contribute watershed area to Sawmill Creek are Darien, Willowbrook, Downers Grove, Burr Ridge, Westmont and Unincorporated DuPage County. The general land use characteristics of the watershed can be delineated by I-55. On the north side of I-55 development is relatively dense with residential and commercial uses. On the south side of I-55 within Sawmill Creek watershed, development is very limited because Argonne National Laboratory and the Waterfall Glen Forest Preserve dominate the landscape. Sawmill Creek has several brachial arms. The Northeasternmost branch is called Sawmill Creek East Branch. The East Branch begins, and most greatly affects, the Darien subdivision called Marion Hills. The headwaters begin on the north side of 67th Street. Flow procedes directly south, passing under 67th Street, 68th Street, 69th Street, Roger Road, Plainfield Road, Janet Avenue, Evans Place, and Elm Street. The East Branch exits the Marion Hills area and briefly flows through residential areas of Willowbrook passing underneath 75th Street, Midway Drive, Virginia Court and 79th Street. The East Branch enters unincorporated areas and passes under 60th Place and Clarendon Hills Road. The branch continues south to pass underneath I-55. The bearing of the stream changes to the southwest where the East Branch passes underneath Webster Avenue and Leonard Drive. West of Leonard Drive, the East Branch confluences with the Sawmill Creek Main Stem. The Sawmill Creek West Branch begins within the City of Darien on the South side of Plainfield Road, west of Bailey Road. The branch enters Lake Darien and is released to the south passing under Lakeview Drive. Several hundred feet downstream, the West Branch flows under Joliet Road and I-55. On the downstream side of I-55, the West Branch enters Waterfall Glen Forest Preserve, confluences with Wards Creek and bears to the southeast. A few hundred feet downstream, the West Branch joins Main Stem Sawmill Creek. Two branches, Tributary 1 and Tributary 3 are found within the Argonne National Laboratory. The southernmost of these branches is known as Freund Brook. Both branches flow from west to east, confluencing with the Sawmill Creek Main Stem on the eastern edge of Argonne National Laboratory.


Main Stem Sawmill Creek finds its headwaters within the City of Darien, just north of 75th Street and southeast of Plainfield Road. The Main Stem passes south through a slightly higher density residential that that seen for the East Branch. Main Stem waters proceed underneath 75th Street, Walnut Street, 79th Street and Portsmouth Drive. Flow turns to the southwest, passing flow under Nantucket Drive and Joliet Road. Flow assumes a southeast course and passes under I-55, confluencing with the East Branch shortly thereafter. The Main Stem changes bearing to the southwest, entering the Waterfall Glen Forest Preserve, passing under Cass Avenue and confluencing with the Sawmill Creek West Branch. The Main Stem proceeds in a serpentine fashion to the south through the Argonne National Laboratory, crossing Eastwood Drive and confluencing with Sawmill Creek Tributary No.1 (Freund Brook). Continuing through Argonne, the Main Stem passes underneath Freud Road and Bluff Road. The Main Stem undergoes a rapid drop in profile and passes underneath the Santa Fe Railroad to enter the Des Plaines River. 3.6.1.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Sawmill Creek. Discharges for the 10-year, 50-year, and 100-year floods for Sawmill Creek, Sawmill Creek Tributary No. 1, Sawmill Creek Tributary No. 3, were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses for the streams studied in detail in the Unincorporated Areas of DuPage County, Illinois, are presented below in Table SWSW.1.

Table SWSW.1: USGS Stream Gages Used for Hydrologic Analysis of Sawmill Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Sawmill Creek near Lemont 05533400 13.00 15 The flood discharges of specified return periods were compared with those calculated by the SCS using the TR-20 program for Sawmill Creek and East Branch Sawmill Creek. The SCS discharges for Sawmill Creek were


found suitable, but the discharges for East Branch Sawmill Creek were found to be lower than the acceptable range of discharges calculated using the State Standard Method. Therefore, the discharges submitted to the SWS for East Branch Sawmill Creek are Harza values. All of the discharges for the detailed study areas were sent to the SWS for review and approval, and the 100-year discharges were certified by the DOWR for use in its floodplain regulation program. Data are located in a repository of flood-related data administered by the SWS. Discharges for the 2-, 5-, 10-, 25-, and 100-year floods were available from the SCS TR-20 model of Sawmill Creek (U.S. Department of Agriculture, 1965). Discharges for the 10- and 100-year floods on East Branch Sawmill Creek and West Branch Sawmill Creek in the City of Darien were calculated by Harza using regional flood frequency equations (Illinois Department of Transportation, Magnitude and Frequency of Floods in Illinois, 1973). Data for the three detailed study streams were plotted separately on log-normal probability paper, and the 50- and 500-year floods were estimated by straight-line interpolation and extrapolation, respectively. The 500-year flood discharge estimates are less reliable than the others because: 1) the precipitation-frequency relationship, required for the TR-20 program, is not well defined for this rare event, and 2) the average period of record for stream gages used to derive the regional equations is about 30 years. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SWSW.2. Table SWSW.2: Sawmill Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Sawmill Creek - East Branch

- at 79th Street 2.10 253 410 481 690 - at 75th Street 0.99 178 290 340 480 - at Elm Street 0.55 123 200 235 332 - at Janet Road 0.32 89 140 170 239 - at Rodger Road 0.24 75 120 140 200 - at 68th Street 0.20 65 103 120 170

Sawmill Creek -

- approx. 80 ft u/s of Bluff Road 13.00 1,363 * 2,588 * - at 79th Street 1.24 294 476 566 800 - at 75th Street 0.97 243 394 467 660 Sawmill Creek -


Tributary 1 - at river mile 0.23 2.33 324 * 617 *

Sawmill Creek - Tributary 3

- at mouth 1.14 241 427 559 960

Sawmill Creek - West Branch

- at I-55 0.75 178 290 345 495 - near Cass School 0.58 149 245 290 420 - near Bay View 0.42 146 238 285 402

3.6.1.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Stream cross-sections and bridge sections for East Branch Sawmill Creek, Sawmill Creek, and West Branch Sawmill Creek were surveyed using land survey techniques. All of the cross sections on Sawmill Creek and the cross sections downstream from 75th Street on East Branch Sawmill Creek were surveyed by the SCS; upstream sections were surveyed by Harza. All sections on West Branch Sawmill Creek were surveyed by Harza. Water-surface elevations for floods of the selected recurrence intervals were computed using hydraulic models for East Branch Sawmill Creek and Sawmill Creek prepared by the SCS (Des Plaines River Watershed


Steering Committee, 1976). Both models were extended by Harza to cover the entire stream within the City of Darien. The models were developed using the SCS WSP-2 step-backwater program (U.S. Department of Agriculture, 1976). Mathematical relationships used in the model include the standard step-backwater procedure which estimates total energy at each cross section and accounts for friction losses between sections using Manning’s formula. The model requires discharge, cross-section geometry, bridge geometry, starting water-surface elevation, and roughness data to simulate flood flow conditions. West Branch Sawmill Creek was modeled by Harza using the WSP-2 program. Starting water-surface elevations for East Branch Sawmill Creek, Sawmill Creek, and West Branch Sawmill Creek were determined from previous studies by the SCS (Des Plaines River Watershed Steering Committee, 1976). Roughness coefficients for East Branch Sawmill Creek, Sawmill Creek, and West Branch Sawmill Creek were assigned on the basis of field inspection and previous analyses by the SCS. Please refer to Table SWSW.3 for more details. Table SWSW.3: Sawmill Creek Manning’s “n” Values



-East Branch Sawmill Creek 0.035 - 0.075 0.040 - 0.095 -Sawmill Creek 0.055 - 0.065 0.065 - 0.090 -Sawmill Creek Tributary No. 1 0.035 - 0.080 0.070 - 0.090 -Sawmill Creek Tributary No. 3 0.040 - 0.100 0.050 - 0.120 -West Branch Sawmill Creek 0.040 - 0.060 0.035 - 0.045 The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevation as shown on the profiles are, therefore, considered valid only if hydraulic structures, in general, remain unobstructed and if channel and overbank conditions remain essentially the same as ascertained during this study. All elevations are referenced from National Geodetic Vertical Datum of 1929 (NGVD); elevation reference marks used in the study are shown on the maps. 3.6.1.4 Flood Boundaries


To reference the flood boundaries for Sawmill Creek, see Map Panels: 0905, 0906, 0908, 0909, 1001, 1002 and 1005. 3.6.1.5 Floodways

The floodways for East Branch Sawmill Creek were determined from the HUD-15 computer program (U.S. Department of Agriculture, 1977). Floodways were computed without consideration of backwater from the receiving streams.



FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Sawmill Creek (SWSW)SWSW0001 4,136 80 383 6.8 623.7 623.7 623.7 0.01

SWSW0002 8,240 160 787 3.3 652.0 652.0 652.0 0.01

SWSW0003 11,850 380 1,425 1.7 659.7 659.7 659.7 0.01 2

SWSW0004 14,352 150 718 3.1 665.3 665.3 665.3 0.01

SWSW0005 16,016 170 578 2.3 669.2 669.2 669.2 0.01

SWSW0006 19,054 260 551 2.2 673.9 673.9 673.9 0.01

SWSW0007 21,603 70 439 1.1 680.9 680.9 680.9 0.01

SWSW0008 25,020 99 299 2.1 694.5 694.5 694.6 0.11

SWSW0009 26,910 266 215 2.6 709.5 709.5 709.6 0.11

SWSW0010 28,414 40 104 4.5 721.5 721.5 721.6 0.11


AND INCORPORATED AREAS SAWMILL CREEK (SWSW)


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


West Branch Sawmill Creek (SWSW)

SWSW0013 20,192 85 572 0.6 707.3 707.3 707.4 0.11

SWSW0014 20,362 60 291 1.2 707.3 707.3 707.4 0.11

SWSW0015 20,812 28 78 4.4 711.5 711.5 711.6 0.11

SWSW0016 21,383 39 70 4.2 715.1 715.1 715.2 0.11

SWSW0017 21,683 57 338 0.9 726.2 726.2 726.3 0.11

SWSW0018 22,630 61 188 1.5 728.4 728.4 728.5 0.11

SWSW0019 22,825 55 161 1.8 729.9 729.9 723.0 0.11

SWSW0020 23,035 88 226 1.3 731.8 731.8 731.9 0.11

SWSW0021 23,315 15 265 1.1 733.2 733.2 733.3 0.11

SWSW0022 23,693 66 85 3.3 734.2 734.2 734.3 0.11

SWSW0023 24,696 53 279 0.4 738.7 738.7 738.8 0.11

SWSW0024 25,116 402 2,131 0.1 738.7 738.7 738.8 0.11

SWSW0025 25,945 29 24 3.4 742.0 742.0 742.1 0.11

SWSW0026 26,679 15 16 5.1 759.0 759.0 759.1 0.11


AND INCORPORATED AREAS WEST BRANCH SAWMILL CREEK (SWSW)

In feet above confluence with Sawmill Creek1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


East Branch Sawmill Creek (SWSW)

SWSW0030 27,709 174 308 1.8 700.4 700.4 700.5 0.11

SWSW0031 29,232 67 181 2.7 705.2 705.2 705.3 0.11

SWSW0032 30,478 272 292 1.4 710.6 710.6 710.7 0.11

SWSW0033 30,718 147 263 1.3 714.8 714.8 714.9 0.11

SWSW0034 31,906 171 274 1.2 715.2 715.2 715.3 0.11

SWSW0035 32,376 119 71 3.3 717.4 717.3 717.4 0.11 2

SWSW0036 33,386 59 70 2.4 720.0 720.0 720.1 0.11

SWSW0037 34,493 231 515 0.3 724.1 724.1 724.2 0.11

SWSW0038 36,496 304 543 0.2 724.1 724.1 724.2 0.11

SWSW0039 36,746 386 1,173 0.1 724.1 724.1 724.2 0.11

FEDERAL EMERGENCY MANAGEMENT AGENCY FLOODWAY DATADUPAGE COUNTY, ILAND INCORPORATED AREAS EAST BRANCH SAWMILL CREEK (SWSW)

In feet above confluence with Sawmill Creek2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

585

590

595 595

600 600

605 605

610 610

615 615

620 620

625 625

630 630

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

(SW

SW)

136P

SWSW

0001

CONF

LUEN

CE W

ITH

DES

PLAI

NES

RIVE

R

RAIL

ROAD


50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM DES PLAINES RIVER

*DATA NOT AVAILABLE

615

620

625 625

630 630

635 635

640 640

645 645

650 650

655 655

660 660

5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

(SW

SW)

137P

SWSW

0002

BLUF

F RO

AD

FRON

T ST

REET

EAST

WOO

D DR

IVE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED



640

645

650 650

655 655

660 660

665 665

670 670

675 675

11500 12000 12500 13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

(SW

SW)

138P

SWSW

0003

SWSW

0004

SWSW

0005

CONF

LUEN

CE O

F W

ARDS

CRE

EK

CASS

AVE

NUE


50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED



660

665

670 670

675 675

680 680

685 685

690 690

695 695

18000 18500 19000 19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

(SW

SW)

139P

SWSW

0006

SWSW

0007

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 1

INTE

RSTA

TE 5

5

JOLI

ET R

OAD

NANT

UCKE

T DR

IVE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED



CONF

LUEN

CE O

F

680

685

690 690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

24500 25000 25500 26000 26500 27000 27500 28000 28500 29000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

(SW

SW)

140P

SWSW

0008

SWSW

0009

SWSW

0010

75TH

STR

EET

LIM

IT O

F DE

TAIL

ED S

TUDY

LEGEND

500-YEAR FLOOD*

100-YEAR FLOOD

50-YEAR FLOOD*10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE DOWNSTREAM OF 25,000 FEETABOVE CONFLUENCE WITH W. BRANCH DUPAGE RIVER

685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

730 730

20000 20200 20400 20600 20800 21000 21200 21400 21600 21800 22000 22200 22400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SAWMILL CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

SAW

MIL

L CR

EEK

(SW

SW)

141P

SWSW

0013

SWSW

0014

SWSW

0015

SWSW

0016

SWSW

0017

LIM

IT O

F DE

TAIL

ED S

TUDY

JOLI

ETE

ROAD

WEI

R

COAC

HMAN

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT NO. 1

CULVERT

CULVERT

715

720

725 725

730 730

735 735

740 740

22400 22600 22800 23000 23200 23400 23600 23800 24000 24200 24400 24600 24800 25000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

SAW

MIL

L CR

EEK

(SW

SW)

142P

SWSW

0018

SWSW

0019

SWSW

0020

SWSW

0021

SWSW

0022

SWSW

0023

LAKE

VIEW

DRI

VE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT NO. 5CULVERT NO. 4

CULVERT NO. 3

CULVERT NO. 2

THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR PROFILE TO BE SHOWN SEPARATELY

725

730

735 735

740 740

745 745

750 750

755 755

760 760

25000 25200 25400 25600 25800 26000 26200 26400 26600 26800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

SAW

MIL

L CR

EEK

(SW

SW)

143P

SWSW

0024

SWSW

0025

SWSW

0026

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500 33000 33500 34000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SAWMILL CREEK AT DES PLAINES RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

SAW

MIL

L CR

EEK

(SW

SW)

144P

SWSW

0030

SWSW

0031

SWSW

0032

SWSW

0033

SWSW

0034

SWSW

0035

SWSW

0036

79TH

STR

EET

VIRG

INIA

COU

RT

MID

WAY

DRI

VE

75TH

STR

EET

ELM

STR

EET

EVAN

S PL

ACE

JANE

T AV

ENUE

PLAI

NFIE

LD R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE W

ITH

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

1

700

705

710 710

715 715

720 720

725 725

34000 34500 35000 35500 36000 36500 37000 37500 38000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SAWMILL CREEK AT DES PLAINES RIVERH

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

EAST

BRA

NCH

SAW

MIL

L CR

EEK

(SW

SW)

145P

SWSW

0037

SWSW

0038

SWSW

0039

ROGE

R RO

AD

69TH

STR

EET

68TH

STR

EET

67TH

STR

EET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


655

660

665 665

670 670

675 675

680 680

685 685

690 690

13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAR

DS C

REEK

(SW

SW)

146P

SWSW

0011

CONF

LUEN

CE W

ITH

SAW

MIL

L CR

EEK

NORT

HGAT

E DR

IVE

CONF

LUEN

CE O

F W

EST

BRAN

CH S

AWM

ILL

CREE

K


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

670

675

680 680

685 685

690 690

695 695

700 700

705 705

19000 19500 20000 20500 21000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAR

DS C

REEK

(SW

SW)

147P

SWSW

0012

S FR

ONTA

GE R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

660

665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

18000 18500 19000 19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE OF SAWMILL CREEK AT DES PLAINES RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DU P

AGE

COUN

TY, I

LAN

D IN

CORP

ORAT

ED A

REAS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 1 (S

WSW

)

148P

SWSW

0027

SWSW

0028

SWSW

0029

CONF

LUEN

CE W

ITH

SAW

MIL

L CR

EEK

UNNA

MED

ROA

D

LEOM

AR L

ANE

WES

TERN

AVE

NUE

INTE

RSTA

TE 5

5

CLAR

ENDO

N HI

LLS

ROAD

81ST

STR

EET


50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

680

685

690 690

695 695

700 700

24500 25000 25500 26000 26500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE OF SAWMILL CREEK AT DES PLAINES RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DU P

AGE

COUN

TY, I

LAN

D IN

CORP

ORAT

ED A

REAS

FLOO

D PR

OFIL

ES

SAW

MIL

L CR

EEK

TRIB

UTAR

Y NO

. 1 (S

WSW

)

149P

WIL

LIAM

DRI

VE

79TH

STR

EET

CONF

LUEN

CE O

F EA

ST B

RANC

H


100-YEAR FLOOD

50-YEAR FLOOD*10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

SAW

MIL

L CR

EEK

3.6.2 Wards Creek (SWWD)

3.6.2.1 Tributary Description Wards Creek is located in DuPage County, in northeastern Illinois, approximately 30 miles west of downtown Chicago. The Wards Creek Watershed covers 3.11 square miles (1990 acres). This watershed includes parts of the Villages of Downers Grove, Woodridge, and Darien, and areas in unincorporated Downers Grove North and South Townships. Wards Creek joins the mainstem of Sawmill Creek several hundred feet downstream of passing underneath I-55, but for the purposes of modeling, the I-55 barrier is considered Wards Creek’s downstream-most cut-off.

Wards Creek Mainstem (Reach #1) finds its headwaters west of Dunham Road. This headwater area is actually an interbasin transfer zone in which the golf course west of Dunham Road directs low flow into Prentiss Creek of the East Branch DuPage River, but under large storm events routes flow into Wards Creek. The mainstem winds its way through the Dunham wetlands and passes east underneath Lemont Road to another wetland area known as Farm Lake. Once through this area, Wards Creek enters a series of complex drop boxes and pathways known as the Farmingdale Basin region. Downstream of Farmingdale, the channel returns and turns to the south, passing under 79th Place culvert and 80th Street culvert, and opening up into Bruce Lake. A weir located on the east side of the lake directs flow into a channel that passes flow underneath Fairmount Avenue, Landsfield Avenue, Woodcreek Court and Plainfield Road. Downstream of Plainfield Road the channel opens up forming another wetland area controlled by the culverts located downstream at Kearney Road. The creek passes through approximately 510 ft of conduit and exits on the south side of Rosehill Court. Wards Creek then proceeds through the Carriage Green Golf Course, encountering two cart path bridges and a cattle-crossing culvert. The creek then exits the golf course and passes through Creekside Lane Culvert, 86th Street Culvert, the Tara Hill and Swan Lake Storage Facilies, Lake Ridge Drive Culvert, Kentwood Court Culvert and Weir, and Carlisle Court Culvert. The Mainstem reenters the Carriage Green Golf Course, passes under two cart path bridges and a berm before exiting the system at the 6’ x 6’ reinforced concrete box culvert that passes under I-55.

Reach #2 is found in the northeastern sections of the Wards Creek Watershed. Reach #2 has its headwaters with the Lake in the Woods ponds, and releases flow to the southwest. After passing under Redondo Drive, Reach#2 opens up into Woodglen Pond. The creek then flows through culverts at Woodglen Lane and Plainfield Road. The channel bottom drops steeply and joins the Mainstem (Reach #1) at the Mallard Landing pond.


Reach #3 is known only as the Lyman Avenue Basin. This area drains the north-central part of the watershed that is highly commercial and retail. The Lyman Avenue Basin is a collection point for these waters before flowing into the Farmingdale Ridge Basin.

Reach #4 drains the central part of the watershed from the highly residential Brookeridge subdividion. Lake Brookeridge and adjacent Donut Lake are the headwaters of this reach, but it is only a short distance north, flowing under Plainfield Road, when Reach #4 confluences with the Mainstem at Bruce Lake.

Reach #6 is completely on the Carriage Green Golf Course found in the southeastern portion of the watershed. Reach #6 has its headwaters at the Carriage Green Golf Course Pond. The water then flows through 125 ft of conduit before it is daylighted again, dropping steeply towards the confluence with the Mainstem.

In general, the Wards Creek Watershed is a mix of land use types. The Northern section of the watershed is highly developed for commercial and retail purposes. The far northwest, and the eastern side of the watershed are large open areas maintained as golf courses. The central and central-west sections are largely residential, but seem to be less dense in nature than typical residential areas found in DuPage County.

3.6.2.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Wards Creek. Discharges for the 10-year, 50-year, and 100-year floods for Wards Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table SWWD.1. Table SWWD.1: Wards Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Wards Creek

- at I-55 0.75 171 * 207 *


3.6.2.3 Hydraulic Analysis Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles. Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. 3.6.2.4 Flood Boundaries To reference the flood boundaries for Wards Creek, see Map Panels: 0907, 0908, 1001 and 1002. 3.6.2.5 Floodways

No floodway information is currently available for this tributary. 3.6.2.6 Flood Profiles Please reference attached Flood Profile Sheets.


655

660

665 665

670 670

675 675

680 680

685 685

690 690

13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAR

DS C

REEK

(SW

SW)

146P

SWSW

0011

CONF

LUEN

CE W

ITH

SAW

MIL

L CR

EEK

NORT

HGAT

E DR

IVE

CONF

LUEN

CE O

F W

EST

BRAN

CH S

AWM

ILL

CREE

K


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

670

675

680 680

685 685

690 690

695 695

700 700

705 705

19000 19500 20000 20500 21000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WAR

DS C

REEK

(SW

SW)

147P

SWSW

0012

S FR

ONTA

GE R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

3.7 West Branch DuPage River (WB)

3.7.1 Main Stem (WBWB)

3.7.1.1 Tributary Description The West Branch DuPage River is a 42.2 square mile watershed (not including tributary watershed areas) found in the western third of DuPage County, Illinois. The communities that contribute watershed area to the West Branch DuPage River Main Stem are: Hanover Park, Roselle, Bartlett, Wayne, Carol Stream, West Chicago, Winfield, Warrenville, Naperville and Unincorporated DuPage County. The West Branch DuPage River enters DuPage County within the Village of Hanover Park, on the northern edge of the county. From the northern Cook-DuPage County border, the West Branch flows directly south, passing under the Elgin-O’Hare Expressway, Lake Street and Arlington Drive before bearing west through the Mallard Lake Forest Preserve. The West Branch confluences with West Branch Tributary No. 1 in the Mallard Lake Forest Preserve and continues west to pass under County Farm Road. The Main Stem enters the Hawk Hollow Forest Preserve on the south side of Bartlett, joins West Branch Tributary No. 2 and bears immediately to the south. The West Branch passes through the Chicago Central and Pacific Railroad, Schick Road, Army Trail Road, the West Branch Forest Preserve and North Avenue, just downstream of which the Main Stem confluences simultaneously with the West Branch DuPage River Tributary No. 3 from the west and West Branch DuPage River Tributary No. 4 from the east. The Main Stem bears to the southeast, passes through the Timber Ridge Forest Preserve, and joins Klein Creek Tributary just upstream of Geneva Road. Continuing to the south, the Main Stem passes under Highlake Road and the Chicago and Northwestern Railroad, joining with West Branch Tributary No. 5 on the upstream side. The West Branch passes under Beecher, turns to the west and proceeds through the West DuPage Woods Forest Preserve, confluencing with Winfield Creek. The river bearing resumes a southerly course, passing under Roosevelt Road, and Gary’s Mill Road confluencing with Kress Creek before crossing under Mack Road. The West Branch proceeds to the southeast, passes under Williams Road and joins Springbrook No. 1 before crossing under the Illinois Prairie Path / Butterfield Road. Flow swings back to the southwest, passing under Warrenville Main Street, Warrenville Road and the East-West Tollway (I-88), on the downstream side of which the Main Stem confluences with Ferry Creek Tributary. The Main Stem flows through the McDowell Grove Forest Preserve, changing flow to the southeast, passing through Fawell Dam, and Ogden Avenue, the downstream side of which the West Branch confluences with Cress Creek Tributary. Flow continues through


the City of Naperville passing under the Burlington Northern Railroad, Jefferson Avenue, Eagle Street, Webster Street, Main Street, and Washington Street on the downstream side of which Steeple Run Watershed joins the Main Stem. Proceeding south, flow continues through Hillside Road, Gartner Road, and Hobson Road, on either side of which West Branch Tributaries No. 6 and 7 join the Main Stem. The West Branch continues south, crossing under 75th Street and Bailey Road, confluencing with the Winding Creek Tributary on the south side of Bailey Road. The West Branch continues its course and just before exiting DuPage County for Will County, the West Branch joins the South of Foxcroft Tributary. 3.7.1.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for the West Branch DuPage River Main Stem. Discharge-frequency data for the West Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). The USGS stream gages used for the hydrologic analyses of the West Branch DuPage River studied in detail are presented in Table WBWB.1 below: Table WBWB.1: USGS Stream Gages Used for Hydrologic Analysis of the West Branch DuPage River

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) West Branch DuPage River at Naperville 05540130 123.0 1

West Branch DuPage River near Warrenville 05540095 90.4 10


A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBWB.2. Table WBWB.2: West Branch DuPage River Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr West Branch DuPage River

- approximately 475 ft u/s of confluence with unnamed creek (south of 87th Street) 124.5 3,545 4,970 5,655 7,575

- at DuPage-Will County line 123.0 3,510 4,920 5,600 7,500

- at Hillside Road 107.3 3,075 4,000 4,400 5,250 - at Ogden Avenue 105.0 2,880 3,740 3,960 5,000 - u/s of Fawell Dam 100.0 2,900 4,100 4,600 5,850 - at confluence with

Kress Creek 80.3 2,460 3,460 3,850 4,900 - above mouth, Kress Ck 62.0 1,800 2,600 2,900 3,900

- at Roosevelt Road 58.5 1,700 2,400 2,700 3,550 - at North Avenue 28.5 970 1,360 1,540 1,980

- near Jefferson Street in Hanover Park 16.4 730 1,010 1,160 1,460

- at Lake Street 10.1 600 830 930 1,170 - at Irving Park Road 4.70 335 460 505 640 3.7.1.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross sections used for the West Branch DuPage River are identical to those used in a previous Floodplain Information Report (USACE, 1975). Channel portions of these cross sections were field surveyed, while overbank portions were determined photogrammetrically. Water-surface profiles for West Branch DuPage River were developed through use of the USACE HEC-2 step-backwater computer program


(USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Starting elevations for the West Branch DuPage River were derived from the Flood Plain Information Report (USACE, 1975). Stream mileages for the West Branch DuPage River and Kress Creek were obtained from the Hydrologic Investigations Atlases (U.S. Department of the Interior, 1965). Starting water-surface elevations for the tributaries were determined from the West Branch hydraulic model (U.S. Department of Agriculture, 1973). Starting water-surface elevations for the West Branch DuPage River model in Schaumburg were obtained from downstream flood profiles prepared by the USACE for the Hanover Park FIS (U.S. Department of Housing and Urban Development, unpublished). Starting elevations were determined from the Poplar Creek hydraulic model. Roughness coefficients (Manning’s “n”) for West Branch DuPage River were estimated by field inspection and by comparison of computed profiles with high-water marks. For further information regarding Manning’s “n” information refer to Table WBWB.3. Table WBWB.3: West Branch DuPage River Manning’s “n” Values



- West Branch DuPage River 0.035 - 0.050 0.040 - 0.100 3.7.1.4 Flood Boundaries To reference the flood boundaries for the West Branch DuPage River, see Map Panels: 0102, 0103, 0105, 0106, 0108, 0109, 0201, 0202, 0204, 0402, 0403, 0405, 0406, 0408, 0409, 0501, 0507, 0702, 0703, 0705, 0706, 0709, 0801, 0804, 0807 and 0808. 3.7.1.5 Floodways



FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


West Branch DuPage River (WBWB)

WBWB0001 12,038 410 2,435 2.3 647.1 647.1 647.2 0.11

WBWB0002 14,002 402 1,428 3.9 650.1 650.1 650.2 0.11

WBWB0003 16,777 217 1,543 3.6 654.1 654.1 654.2 0.11

WBWB0004 19,660 205 1,683 3.3 657.3 657.3 657.4 0.11 2

WBWB0005 20,580 154 1,200 4.7 658.5 658.5 658.6 0.11

WBWB0006 22,106 302 2,163 2.6 661.5 661.5 661.6 0.11

WBWB0007 24,614 400 1,475 3.8 663.1 663.1 663.2 0.11

WBWB0008 26,343 270 1,692 3.3 664.2 664.2 664.3 0.11

WBWB0009 29,106 450 1,059 4.2 669.6 669.6 669.6 0.01

WBWB0010 29,821 616 3,152 1.4 670.3 670.3 670.3 0.01

WBWB0011 30,953 166 1,153 3.8 670.9 670.9 671.0 0.11

WBWB0012 31,409 91 876 5.0 671.9 671.9 672.0 0.11

WBWB0013 32,344 122 1,192 3.7 673.4 673.4 673.5 0.11

WBWB0014 33,511 80 646 6.8 674.9 674.9 674.9 0.01

WBWB0015 34,459 346 2,074 2.1 676.7 676.7 676.8 0.11

WBWB0016 36,869 330 1,636 2.7 678.0 678.0 678.1 0.11

WBWB0017 39,519 550 1,585 2.8 680.1 680.1 680.2 0.11


AND INCORPORATED AREAS WEST BRANCH DUPAGE RIVER (WBWB)

In feet above confluence with DuPage River2 Actual floodway width cannot be shown on FIRM due to redelineation of floodplain

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBWB0018 41,159 400 1,221 3.2 681.5 681.5 681.6 0.11

WBWB0019 42,423 190 1,238 3.2 682.1 682.1 682.2 0.11

WBWB0020 46,993 720 7,287 0.7 691.1 691.1 691.2 0.11

WBWB0021 51,222 2,040 11,817 0.4 691.5 691.5 691.5 0.01

WBWB0022 52,928 244 1,830 2.5 691.5 691.5 691.6 0.11

WBWB0023 53,337 210 1,530 3.0 691.7 691.7 691.8 0.11 2

WBWB0024 55,739 290 1,779 2.6 692.8 692.8 692.9 0.11

WBWB0025 57,580 115 1,031 4.3 693.8 693.8 693.9 0.11

WBWB0026 57,804 189 1,229 3.6 694.6 694.6 694.7 0.11

WBWB0027 58,983 300 2,182 2.0 695.3 695.3 695.4 0.11

WBWB0028 59,484 240 1,369 3.2 695.6 695.6 695.7 0.11

WBWB0029 61,496 392 1,765 2.5 696.7 696.7 696.8 0.11

WBWB0030 62,029 433 2,213 2.0 697.5 697.5 697.6 0.11

WBWB0031 63,679 444 2,383 1.7 697.9 697.9 698.0 0.11

WBWB0032 63,822 462 2,677 1.5 698.5 698.5 698.6 0.11

WBWB0033 65,356 325 987 4.2 698.8 698.8 698.9 0.11

WBWB0034 65,591 288 990 4.1 699.1 699.1 699.2 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBWB0035 69,409 294 1,600 2.6 702.2 702.2 702.3 0.11

WBWB0036 71,400 226 1,352 2.8 703.0 703.0 703.1 0.11

WBWB0037 74,518 223 1,432 2.7 705.0 705.0 705.1 0.11

WBWB0038 76,742 499 2,249 1.3 706.1 706.1 706.2 0.11

WBWB0039 78,384 192 1,269 2.3 706.5 706.5 706.6 0.11

WBWB0040 79,605 195 1,112 2.3 707.2 707.2 707.3 0.11

WBWB0041 79,776 198 1,157 2.3 707.5 707.5 707.6 0.11

WBWB0042 81,714 265 1,407 1.9 708.2 708.2 708.3 0.11

WBWB0043 88,642 339 1,438 1.9 710.9 710.9 711.0 0.11

WBWB0044 91,720 330 1,804 1.5 712.2 712.2 712.3 0.11

WBWB0045 93,630 107 698 3.4 713.1 713.1 713.2 0.11

WBWB0046 93,877 107 729 3.3 713.3 713.3 713.4 0.11

WBWB0047 94,400 107 783 3.1 713.8 713.8 713.9 0.11

WBWB0048 94,739 200 1,159 2.1 714.7 714.7 714.8 0.11

WBWB0049 95,051 540 2,225 1.1 714.9 714.9 715.0 0.11

WBWB0050 100,103 225 1,063 2.3 716.7 716.7 716.8 0.11

WBWB0051 101,779 709 3,079 0.8 720.5 720.5 720.6 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBWB0052 102,037 760 3,901 0.6 721.5 721.5 721.6 0.11

WBWB0053 104,158 323 1,360 1.4 721.6 721.6 721.7 0.11

WBWB0054 108,649 647 1,792 1.1 722.5 722.5 722.6 0.11

WBWB0055 111,349 949 2,311 0.8 724.3 724.3 724.4 0.11

WBWB0056 112,617 219 1,010 1.9 726.8 726.8 726.9 0.11

WBWB0057 115,066 154 650 2.4 729.4 729.4 729.4 0.01

WBWB0058 116,204 418 1,919 0.8 730.1 730.1 730.2 0.11

WBWB0059 118,019 230 1,139 1.4 730.6 730.6 730.7 0.11

WBWB0060 119,018 206 736 2.1 731.5 731.5 731.6 0.11

WBWB0061 120,192 243 944 1.6 732.9 732.9 733.0 0.11

WBWB0062 122,229 514 1,919 0.8 733.4 733.4 733.5 0.11

WBWB0063 125,483 446 939 1.6 734.3 734.3 734.4 0.11

WBWB0064 128,591 358 775 1.8 737.8 737.8 737.9 0.11

WBWB0065 129,669 582 1,064 1.3 738.8 738.8 738.9 0.11

WBWB0066 131,994 113 376 3.8 742.0 742.0 742.1 0.11

WBWB0067 133,912 366 1,432 1.0 746.4 746.4 746.5 0.11

WBWB0068 136,354 446 1,200 1.2 747.5 747.5 747.6 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBWB0069 138,028 369 1,737 1.3 748.9 748.9 749.0 0.11

WBWB0070 141,759 182 597 2.4 752.9 752.9 753.0 0.11

WBWB0071 146,706 340 1,063 1.3 758.4 758.4 758.5 0.11

WBWB0072 150,725 300 694 1.7 764.6 764.6 764.7 0.11

WBWB0073 153,225 270 928 1.3 767.6 767.6 767.7 0.11

WBWB0074 155,624 80 766 1.5 768.5 768.5 768.6 0.11

WBWB0075 158,003 100 312 3.7 771.5 771.5 771.6 0.11

WBWB0076 159,859 294 593 2.0 774.4 774.4 774.5 0.11

WBWB0077 161,936 281 372 2.5 775.9 775.9 776.0 0.11




1

TAB

LE 5

610

620

630 630

640 640

650 650

660 660

670 670

11000 12000 13000 14000 15000 16000 17000 18000 19000 20000 21000 22000 23000 24000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH DUPAGE RIVER

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

185P

WBW

B000

1

WBW

B000

2

WBW

B000

3

WBW

B000

4

WBW

B000

5

WBW

B000

6

COUN

TY B

OUND

ARY

PRIV

ATE

DRIV

E

BAIL

EY R

OAD

75TH

STR

EET

HOBS

ON R

OAD

CONF

LUEN

CE O

F W

EST

BRAN

CH T

RIBU

TARY

NO.

6

FOOT

BRID

GE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


630

640

650 650

660 660

670 670

680 680

690 690

24000 25000 26000 27000 28000 29000 30000 31000 32000 33000 34000 35000 36000 37000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

186P

WBW

B000

7

WBW

B000

8

WBW

B000

9

WBW

B001

0

WBW

B001

1

WBW

B001

2

WBW

B001

3

WBW

B001

4

WBW

B001

5

WBW

B001

6

GART

NER

ROAD

HILL

SIDE

ROA

D

WAS

HING

TON

STRE

ET

MAI

N ST

REET

WEB

STER

STR

EET

EAGL

E ST

REET

JEFF

ERSO

N AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


640

650

660 660

670 670

680 680

690 690

700 700

710 710

37000 38000 39000 40000 41000 42000 43000 44000 45000 46000 47000 48000 49000 50000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

187P

WBW

B001

7

WBW

B001

8

WBW

B001

9

WBW

B002

0

RAIL

ROAD

CONF

LUEN

CE O

F CR

ESS

CREE

K

OGDE

N AV

ENUE

FAW

ELL

DAM

LOW

FLOW

DAM

CONF

LUEN

CE O

F FE

RRY

CREE

K


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

650

660

670 670

680 680

690 690

700 700

710 710

50000 51000 52000 53000 54000 55000 56000 57000 58000 59000 60000 61000 62000 63000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

188P

WBW

B002

1

WBW

B002

2

WBW

B002

3

WBW

B002

4

WBW

B002

5

WBW

B002

6

WBW

B002

7

WBW

B002

8

WBW

B002

9

WBW

B003

0

TOLL

WAY

(I-8

8)TO

LLW

AY (I

-88)

WAR

RENV

ILLE

ROA

D

FOOT

BRID

GE

LOW

FLO

W D

AM

ILLI

NOIS

PRA

IRE

PATH

STAT

E HI

GHW

AY 5

6BU

TTER

FIEL

D RO

AD

CONF

LUEN

CE O

F SP

RING

BRO

OK N

O. 1


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

660

670

680 680

690 690

700 700

710 710

63000 64000 65000 66000 67000 68000 69000 70000 71000 72000 73000 74000 75000 76000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

189P

WBW

B003

1W

BWB0

032

WBW

B003

3

WBW

B003

4

WBW

B003

5

WBW

B003

6

WBW

B003

7

ACCE

SS R

OAD

WIL

LIAM

S RO

AD

MAC

K RO

AD

CONF

LUEN

CE O

F KR

ESS

CREE

K


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

680

690 690

700 700

710 710

720 720

76000 77000 78000 79000 80000 81000 82000 83000 84000 85000 86000 87000 88000 89000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

190P

WBW

B003

8

WBW

B003

9

WBW

B004

0W

BWB0

041

WBW

B004

2

WBW

B004

3

GARY

'S M

ILL

ROAD

(ROO

SEVE

LT R

OAD)

STAT

E RO

UTE

38

CONF

LUEN

CE O

F W

EST

BRAN

CH T

RIBU

TARY

NO.

5


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


680

690

700 700

710 710

720 720

730 730

740 740

89000 90000 91000 92000 93000 94000 95000 96000 97000 98000 99000 100000 101000 102000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

191P

WBW

B004

4

WBW

B004

5

WBW

B004

6

WBW

B004

7

WBW

B004

8

WBW

B004

9

WBW

B005

0

WBW

B005

1

BEEC

HER

AVEN

UE

RAIL

ROAD

HIGH

LAKE

ROA

D

UNNA

MED

ROA

D

GENE

VA R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


680

690

700 700

710 710

720 720

730 730

740 740

102000 103000 104000 105000 106000 107000 108000 109000 110000 111000 112000 113000 114000 115000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

192P

WBW

B005

2

WBW

B005

3

WBW

B005

4

WBW

B005

5

WBW

B005

6

CONF

LUEN

CE O

F KL

EIN

CREE

K

ABAN

DONE

D RA

ILRO

AD

CONF

LUEN

CE O

F W

EST

BRAN

CH T

RIBU

TARY

NO.

3CO

NFLU

ENCE

OF

WES

T BR

ANCH

TRI

BUTA

RY N

O. 4

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


690

700

710 710

720 720

730 730

740 740

115000 116000 117000 118000 119000 120000 121000 122000 123000 124000 125000 126000 127000 128000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

193P

WBW

B005

7

WBW

B005

8

WBW

B005

9

WBW

B006

0

WBW

B006

1

WBW

B006

2

WBW

B006

3

NORT

H AV

ENUE

ST. C

HARL

ES R

OAD

UNNA

MED

ROA

D

UNNA

MED

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


710

720

730 730

740 740

750 750

760 760

128000 129000 130000 131000 132000 133000 134000 135000 136000 137000 138000 139000 140000 141000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

194P

WBW

B006

4

WBW

B006

5

WBW

B006

6

WBW

B006

7

WBW

B006

8

WBW

B006

9

ARM

Y TR

AIL

ROAD

SCHI

CK R

OAD

RAIL

ROAD

PRIV

ATE

BRID

GE

WES

T BR

ANCH

TRI

BUTA

RY N

O. 2


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F CO

UNTR

Y CR

EEK/

720

730

740 740

750 750

760 760

770 770

780

141000 142000 143000 144000 145000 146000 147000 148000 149000 150000 151000 152000 153000 154000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

195P

WBW

B007

0

WBW

B007

1

WBW

B007

2

WBW

B007

3

COUN

TY F

ARM

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


740

750

760 760

770 770

780 780

790 790

800 800

154000 155000 156000 157000 158000 159000 160000 161000 162000 163000 164000 165000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

196P

WBW

B007

4

WBW

B007

5

WBW

B007

6

WBW

B007

7

CONF

LUEN

CE O

F W

EST

BRAN

CH T

RIBU

TARY

NO.

1

ARLI

NGTO

N DR

IVE

U.S.

ROU

TE 2

0FA

RM B

RIDG

E

RAIL

ROAD

COUN

TY B

OUND

ARY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


758

760

762 762

764 764

766 766

768 768

770 770

772 772

5800 6000 6200 6400 6600 6800 7000 7200 7400 7600 7800 8000 8200 8400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 1

(WBW

1)

197P

WBW

1000

1

FORE

ST P

RESE

RVE

ROAD

FOOT

BRID

GE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM WEST BRANCH DUPAGE RIVER

LIM

IT O

F DE

TAIL

ED S

TUDY

650

660

670 670

680 680

690 690

700 700

710 710

50000 51000 52000 53000 54000 55000 56000 57000 58000 59000 60000 61000 62000 63000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

DUP

AGE

RIVE

R (W

BWB)

188P

WBW

B002

1

WBW

B002

2

WBW

B002

3

WBW

B002

4

WBW

B002

5

WBW

B002

6

WBW

B002

7

WBW

B002

8

WBW

B002

9

WBW

B003

0

TOLL

WAY

(I-8

8)TO

LLW

AY (I

-88)

WAR

RENV

ILLE

ROA

D

FOOT

BRID

GE

LOW

FLO

W D

AM

ILLI

NOIS

PRA

IRE

PATH

STAT

E HI

GHW

AY 5

6BU

TTER

FIEL

D RO

AD

CONF

LUEN

CE O

F SP

RING

BRO

OK N

O. 1


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

3.7.2 Cress Creek (WBCC)

3.7.2.1 Tributary Description Cress Creek is a 2694-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to Cress Creek are Naperville and Unincorporated DuPage County. The bulk land use characteristic is single-family houses, but many of the undeveloped areas in the outer fringes of the watershed are quickly being transformed into single-family dwellings or commercial ventures. Much of Cress Creek watershed is placed in conduit. Whether in conduit or not, the stream origins can be found in the corporate ponds south of I-88 and east of Washington Street. Flow proceeds to the southwest, and continues this bearing throughout the stream length. Cress Creek passes under such roads as Diehl Road, Chippewa Drive, Breamar Avenue and Iroquis Avenue before entering the detention areas at the Jefferson School. The creek then proceeds to cross Bauer Road, Washington Street, Main Street, Webster Street, Eagle Street and Mill Street. On the west side of Mill, Cress Creek flows through a large residential subdivision crossing such roads as West Street, Burning Tree Lane, and Zaininger Avenue. Cress Creek exits the subdivison and passes under Ogden Avenue, Royal St. George Drive, and 6th Avenue before confluencing the West Branch DuPage River. 3.7.2.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Cress Creek. For Cress Creek, synthetic frequency-discharge curves were derived using regional statistics developed in the Chicago study. These discharges assume zero skew. Discharges for the 500-year floods of all streams were determined by linear extrapolation of a log probability curve of flood discharges computed for frequencies of up to 100 years. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBCC.1. Table WBCC.1: Cress Creek Summary of Discharges



Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Cress Creek

- at mouth 1.45 325 575 740 1,430 3.7.2.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Both overbank and channel cross sections for Cress Creek were field surveyed. Water-surface elevations for Cress Creek were computed for the 10-, 50-, 100-, and 500-year floods using a HEC-2 computer step-backwater model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973 Starting water-surface elevations for Cress Creek were calculated using the slope/area method. Roughness coefficients (Manning’s “n”) for Cress Creek were estimated by field inspection and by comparison of computed profiles with high-water marks. For further information, refer to Table WBCC.2

Table WBCC.2: Cress Creek Manning’s “n” Values Manning’s “n” Values


- Cress Creek 0.030 0.800 3.7.2.4 Flood Boundaries To reference the flood boundaries for Cress Creek, see Map Panels: 0703, 0706, 0801 and 0804. 3.7.2.5 Floodways


Floodways for streams tributary to the West Branch DuPage River were computed without consideration of backwater flooding from the West Branch. Near the mouth of a few of these streams, therefore, floodway surcharge elevations are below rather than above the 100-year elevations determined by the West Branch backwater and indicated on the flood profiles.



FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Cress Creek (WBCC)WBCC0001 307 505 98 3.9 680.2 673.9 673.9 0.01 2

WBCC0002 1,194 52 101 3.8 680.2 676.5 676.5 0.01 2

WBCC0003 2,059 37 90 4.3 680.2 678.0 678.0 0.01 2

WBCC0004 3,153 35 94 4.1 680.4 680.4 680.4 0.01

WBCC0005 4,105 47 111 3.5 688.2 688.2 688.2 0.01

WBCC0006 5,200 23 51 7.6 690.2 690.2 690.2 0.01

WBCC0007 5,560 47 139 2.8 692.6 692.6 692.6 0.01

WBCC0008 6,065 32 98 3.9 693.0 693.0 693.0 0.01


AND INCORPORATED AREAS CRESS CREEK (WBCC)

In feet above confluence with West Branch DuPage River2 Elevations computed without consideration of backwater effects from West Branch DuPage River

1

TAB

LE 5

660

665

670 670

675 675

680 680

685 685

690 690

695 695

700 700

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

CRES

S CR

EEK

(WBC

C)

150P

WBC

C000

1

WBC

C000

2

WBC

C000

3

WBC

C000

4

WBC

C000

5

WBC

C000

6

WBC

C000

7

WBC

C000

8

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

5TH

AVEN

UE

ROYA

L ST

. GEO

RGE

AVEN

UE

OGDE

N AV

ENUE

ZAIN

INGE

R AV

ENUE

BURN

ING

TREE

LAN

E

FOOT

BRID

GE

WES

T ST

REET

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



3.7.3 Ferry Creek (WBFE)

3.7.3.1 Tributary Description The Ferry Creek watershed covers approximately 12.2 square miles and includes the cities of Warrenville, Naperville, and unincorporated areas of Winfield and Naperville Townships as shown on Figure ES-1. The watershed boundary, shown in Figure ES-2, extends from Fermi National Accelerator Laboratory in the northwest, to the West Branch of the DuPage River to the east, and Country Lakes Golf Course in Naperville in the southwest. The Ferry Creek drainage system consists of approximately 3.8 miles of main stem channel with four major tributaries, listed in order from upstream to downstream: Tributary No. 1, Tributary No. 2, I-88 (East-West Tollway) Ditch Tributary (Tollway Ditch Tributary), and Tributary No. 3. The main stem of Ferry Creek begins at a series of lakes located east of Fermi Laboratory, flows generally to the southeast, and joins the West Branch of the DuPage River approximately 3,000 feet south of I-88, the East-West Tollway. The main stem of Ferry Creek is a well-defined channel at an average slope of 0.2 % with several culvert crossings. The direct drainage area to the main stem is approximately 6.2 square miles. Tributaries No. 1 and No. 2 are roadside ditches that flow east from wetland areas west of Illinois Route 59 through a series of culverts. Tributary No. 1 has a drainage area of approximately 0.3 square miles and Tributary No. 2 has a drainage area of approximately 1.1 square miles. These tributaries join the main stem of Ferry Creek just north of the Prairie Path, and approximately 2,000 feet south of Aurora Way, respectively. The Tollway Ditch, which consists of a portion of grassed channel, a portion of concrete channel, and a series of culverts and closed conduits, drains east and joins the Ferry Creek main stem immediately south of the Tollway. There are two culverts that cross under the East-West Tollway and carry flow from the area north of the Tollway to the Tollway Ditch. The Tollway Ditch has a drainage area of approximately 2.3 square miles. Tributary No. 3 flows through a series of lakes in the Country Lakes Golf Course, proceeds through a network of storm sewers, continues through two detention ponds and an open channel to join the Ferry Creek main stem just south of Diehl Road in the McDowell Grove Forest Preserve. Tributary No. 3 has a drainage area of approximately 2.3 square miles. 3.7.3.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Ferry Creek. Discharges for the 10-year, 50-year, and 100-year floods for Ferry Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.


The USGS stream gages used for the hydrologic analyses of Ferry Creek studied in detail are presented in Table WBFE.1 below: Table WBFE.1: USGS Stream Gages Used for Hydrologic Analysis of Ferry Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Ferry Creek at Warrenville 05540110 4.27 15 A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBFE.2. Table WBFE.2: Ferry Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Ferry Creek

- at East-West Tollway 8.60 380 540 615 805 Ferry Creek Tributary No. 1

- at mouth 2.39 150 265 300 390

3.7.3.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois


and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBFE.3 for further information regarding roughness coefficients. Table WBCC.3: Ferry Creek Manning’s “n” Values



- Ferry Creek 0.015 - 0.040 0.045 - 0.080 3.7.3.4 Flood Boundaries To reference the flood boundaries for Ferry Creek, see Map Panels: 0404, 0405, 0407, 0408, 0409, 0701, 0702, 0703, 0704 and 0705. 3.7.3.5 Floodways


Please reference attached Floodway Data Tables for further information.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Ferry Creek (WBFE)WBFE0006 3,538 150 516 1.2 691.2 690.6 690.6 0.01

WBFE0007 3,854 150 423 1.0 691.2 690.6 690.6 0.01

WBFE0008 4,013 125 426 1.0 691.4 691.4 691.4 0.01

WBFE0009 5,227 227 312 1.4 692.2 692.2 692.3 0.11

WBFE0010 6,230 253 300 1.5 693.2 693.2 693.3 0.11

WBFE0011 7,840 157 263 1.7 695.1 695.1 695.2 0.11

WBFE0012 8,395 111 200 2.2 696.9 696.9 696.9 0.01

WBFE0013 8,712 62 116 3.8 697.2 697.2 697.3 0.11

WBFE0014 9,451 125 154 2.9 699.5 699.5 699.6 0.11

WBFE0015 10,454 122 177 2.5 702.0 702.0 702.1 0.11

WBFE0016 11,141 200 505 0.5 704.1 704.1 704.1 0.01

WBFE0017 12,672 90 151 1.8 704.2 704.2 704.2 0.01

WBFE0018 13,834 76 109 2.4 705.9 705.9 706.0 0.11

WBFE0019 14,441 84 134 2.0 707.1 707.1 707.2 0.11

WBFE0020 15,205 130 334 0.8 711.5 711.5 711.5 0.01

WBFE0021 15,630 49 133 2.0 711.6 711.6 711.6 0.01

WBFE0022 15,780 59 147 1.8 711.8 711.8 711.8 0.01

WBFE0023 16,000 16 46 5.8 712.7 712.7 712.7 0.01


AND INCORPORATED AREAS FERRY CREEK (WBFE)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Ferry Creek (WBFE)WBFE0024 17,475 260 1,219 0.2 716.2 716.2 716.2 0.01

WBFE0025 18,955 246 539 0.3 716.2 716.2 716.2 0.01


AND INCORPORATED AREAS FERRY CREEK (WBFE)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Ferry Creek Tributary No. 1 (WBFE)

WBFE0001 1,135 116 106 2.8 691.2 687.5 687.5 0.01 2

WBFE0002 1,339 32 90 3.3 691.2 689.1 689.1 0.01 2

WBFE0003 3,644 182 293 1.0 697.4 697.4 697.5 0.11

WBFE0004 4,800 26 94 2.6 699.8 699.8 699.9 0.11


AND INCORPORATED AREAS FERRY CREEK TRIBUTARY NO. 1 (WBFE)

In feet above confluence with Ferry Creek2 Elevations computed without consideration of backwater effects from Ferry Creek

1

TAB

LE 5

670

675

680 680

685 685

690 690

695 695

700 700

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

(WBF

E)

151P

WBF

E000

6

WBF

E000

7

WBF

E000

8

WBF

E000

9

WBF

E001

0

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

MCD

OWEL

L RO

AD

CONF

LUEN

CE O

F FE

RRY

CREE

K TR

IBUT

ARY

NO. 1

FORE

ST R

ESER

VE R

OAD

EAST

BOU

ND T

OLLW

AY (I

-88)

WES

T BO

UND

TOLL

WAY

(I-8

8)

FERR

Y RO

AD

PRIV

ATE

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



THE 50-YEAR PROFILE IS TOO CLOSE TO THE 100-YEAR PROFILETO BE SHOWN SEPARATELY

675

680

685 685

690 690

695 695

700 700

705 705

710 710

715 715

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

(WBF

E)

152P

WBF

E001

1

WBF

E001

2

WBF

E001

3

WBF

E001

4

WBF

E001

5

WBF

E001

6

WBF

E001

7

PRIV

ATE

ROAD

FARM

ROA

D

FARM

ROA

D

AURO

RA W

AYRA

ILRO

AD

BUTT

ERFI

ELD

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR PROFILE IS TOO CLOSE TO THE 100-YEAR PROFILETO BE SHOWN SEPARATELY

690

695

700 700

705 705

710 710

715 715

720 720

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

(WBF

E)

153P

WBF

E001

8

WBF

E001

9

WBF

E002

0

WBF

E002

1

WBF

E002

2

WBF

E002

3

WBF

E002

4

HOM

E AV

ENUE

STAT

E RO

UTE

59

PRIV

ATE

BRID

GEAN

D W

EIR


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

700

705

710 710

715 715

720 720

18000 18500 19000 19500 20000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

(WBF

E)

154P

WBF

E002

5

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


670

675

680 680

685 685

690 690

695 695

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH FERRY CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

TRIB

UTAR

Y NO

. 1 (W

BFE)

155P

WBF

E000

1

WBF

E000

2

CONF

LUEN

CE W

ITH

FERR

Y CR

EEK

RAYM

OND

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



675

680

685 685

690 690

695 695

700 700

705 705

2600 2800 3000 3200 3400 3600 3800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

TRIB

UTAR

Y NO

. 1 (W

BFE)

156P


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


685

690

695

700

705

3600 3800 4000 4200 4400 4600 4800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

FERR

Y CR

EEK

TRIB

UTAR

Y NO

. 1 (W

BFE)

157P


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED

CROSS SECTION LOCATIONWBF

E000

3

WBF

E000

4M

C DO

WEL

L RO

ADLI

MIT

OF

DETA

ILED

STU

DY

675

680

685

690

695

700

705

3.7.4 South of Foxcroft (WBFX)

3.7.4.1 Tributary Description The South of Foxcroft Tributary is a 586-acre watershed tributary to the West Branch DuPage River. Communities that contribute watershed area to South of Foxcroft Tributary are Naperville and Unincorporated DuPage County. The overall land use in this small watershed located at the southern border of DuPage County, is strictly suburban residential. The South of Foxcroft Tributary is a highly managed tributary. All aspects of the natural stream channel have been placed in conduit and routed throughout the subdivision. Open-space areas just west of Washington Street and south of 87th Street have open stream channels. The stream flows to the east, passes under Washington Street and joins the West Branch DuPage River just upstream of the DuPage-Will County line. 3.7.4.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for South of Foxcroft Tributary. Discharge-frequency data for East Branch DuPage River, West Branch DuPage River, mouth of Lacey Creek, Klein Creek, Klein Creek Tributary No. 2 were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). Discharges for South of Foxcroft and Unnamed Creek south of 87th Street in the City of Naperville, two tributaries to the West Branch DuPage River, were adjusted to reflect interbasin flow between the two streams. The Hydrologic Investigations Atlas for the Normantown quadrangle indicates that interbasin flow occurred during the October 1954 flood (U.S. Department of the Interior, 1965). Discharges for the two streams were adjusted on a trial-and-error basis until corresponding water-surface elevations in the area of interbasin flow were within 0.5 foot of each other, reflecting gently sloping sheet flow between the two streams. As a result, discharges for the unnamed creek in the area south of 87th Street were


decreased, while those for the creek in the area south of Foxcroft Road were increased. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBFX.1. Table WBFX.1: South of Foxcroft Tributary Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr South of Foxcroft Tributary

- at mouth (discharges increased due to interbasin flow ) 0.30 185 250 285 380 - approximately 1,000 ft d/s of 87th Street 0.20 85 150 185 280 3.7.4.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Both overbank and channel cross sections for South of Foxcroft Tributary were field surveyed. Water-surface elevations for South of Foxcroft Tributary were computed for the 10-, 50-, 100-, and 500-year floods using a HEC-2 computer step-backwater model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Starting water-surface elevations for South of Foxcroft Tributary were calculated using the slope/area method.


Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBFX.2 for further information regarding roughness coefficients. Table WBFX.2: South of Foxcroft Tributary Manning’s “n” Values



- South of Foxcroft Tributary 0.300 0.050 3.7.4.4 Flood Boundaries To reference the flood boundaries for South of Foxcroft, see Map Panels: 0709 and 0807. 3.7.4.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Unnamed Creek (South of Foxcroft Road) (WBFX)

WBFX0001 802 79 212 1.3 646.8 646.8 646.9 0.11

WBFX0002 1,298 307 821 0.4 651.0 651.0 651.0 0.01

WBFX0003 1,890 404 535 0.5 651.1 651.1 651.1 0.01

WBFX0004 2,929 93 200 2.0 654.1 654.1 654.2 0.11

WBFX0005 3,810 129 327 0.6 654.2 654.2 654.2 0.01


AND INCORPORATED AREAS UNNAMED CREEK (SOUTH OF FOXCROFT ROAD) (WBFX)


TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Unnamed Creek (South of 87th Street) (WBFX)

WBFX0101 6,019 26 256 6.1 655.1 655.1 655.1 0.01

WBFX0102 6,441 21 170 6.5 661.3 661.5 661.5 0.01


AND INCORPORATED AREAS UNNAMED CREEK (SOUTH OF 87TH STREET) (WBFX)

In feet above mouth1

TAB

LE 5

630

635

640 640

645 645

650 650

655 655

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

CRE

EK (S

OUTH

OF

FOXC

ROFT

ROA

D) (W

BFX)

158P

WBF

X000

1

WBF

X000

2

WBF

X000

3

WBF

X000

4

COUN

TY B

OUND

ARY

FOOT

BRID

GE

PRIV

ATE

DRIV

E

WAS

HING

TON

STRE

ET

DIKE

87TH

STR

EET


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED




640

645

650 650

655 655

660 660

3000 3250 3500 3750 4000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

CRE

EK (S

OUTH

OF

FOXC

ROFT

ROA

D) (W

BFX)

159P

WBF

X000

5


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY


648

650

652 652

654 654

656 656

658 658

660 660

662 662

664 664

666 666

5000 5200 5400 5600 5800 6000 6200 6400 6600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

CRE

EK (S

OUTH

OF

87TH

STR

EET)

(WBF

X)

160P

WBF

X010

1

WBF

X010

2

COUN

TY B

OUND

ARY

STOR

M S

EWER

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.7.5 Klein Creek (WBKC)

3.7.5.1 Tributary Description The Klein Creek Watershed is comprised of suburban residential communities intermixed with industrial and commercial developments and agricultural lands. The Village of Carol Stream, in Bloomingdale Township, comprises the majority of the watershed with smaller portions of Wayne, Milton and Winfield Townships also contributing. The Villages of Bloomingdale, Glendale Heights and Winfield and portions of unincorporated DuPage County are also within the watershed. Klein Creek has a total watershed area of approximately 12.7 square miles. The headwaters of Klein Creek are comprised of residential developments located in Glendale Heights, east of Schmale Road. From Glendale Heights, Klein Creek flows in a westerly direction through a portion of unincorporated DuPage County and crosses into the Village of Carol Stream approximately 0.5 miles west of Schmale Road. Between Schmale Road and Gary Avenue, Klein Creek consists of open channel wetlands and on-line detention ponds that receive stormwater from numerous commercial developments and shopping centers located in Bloomingdale and Carol Stream. Tributary No. 3, which has a watershed area of approximately 1.1 square miles, enters Klein Creek from the west, just south of the intersection of Gary Avenue and Army Trail Road. At this location, Klein Creek and Tributary No. 3 join on the north side of the old Home Base site retention pond. The Tributary No. 3 watershed consists of residential development (around Mallard Lake), agricultural and vacant land, and some commercial and light industrial developments. From Gary Avenue, Klein Creek flows in a southerly direction through Lies Road and into the Mitchell Lakes area. Mitchell Lakes consists of five individual lakes connected in series and surrounded by recreational open space that is maintained by the Carol Stream Park District. Watershed areas tributary to Mitchell Lakes consist of storm sewered residential developments with single and multi-family structures. Located immediately west of the most downstream lake is Armstrong Park recreational area. This recreational facility is approximately 70 acres in size and is also operated and maintained by the Carol Stream Park District. This facility includes a stormwater retention/recreational lake (Lake George), a dry bottom detention pond and numerous athletic fields and tennis courts. Lake George and the dry bottom detention pond both serve as local stormwater management facilities and are hydraulically connected to Klein Creek, which flows in a southerly direction immediately east of


the park. Residential developments border the park on the north, west and south sides. Illini Drive parallels the southern park boundary. Between Illini Drive and Thunderbird Trail, Klein Creek flows nearly due south and is adjoined by residential development on the east and west sides of the creek. Tributary No. 2 (Thunderbird Creek) enters Klein Creek from the east just upstream of Thunderbird Trail. Tributary No. 2 has a watershed area of approximately 1.4 square miles at the confluence with Klein Creek. The major portion of the Tributary No. 2 watershed is located east of Gary Avenue and is comprised mainly of industrial developments and vacant land. Numerous stormwater detention facilities exist within the industrial facilities in this portion of the watershed. The Tributary No. 2 Watershed west of Gary Avenue consists of single-family residential parcels. From Thunderbird Trail, Klein Creek traverses in a westerly direction to Kuhn Road. Land use along this reach consists of municipal facilities and agricultural land south of the creek with residential and vacant/wooded land north of the creek. Klein Creek flows in a southwest direction from Kuhn Road to its confluence with the West Branch of the DuPage River near Geneva Road. The creek is generally adjoined by agricultural land, green space and forest preserve along this reach, with numerous residential developments set back from the creek. Tributary No. 1, which enters Klein Creek approximately 0.25 miles north of Geneva Road, has a watershed area of approximately 1.2 square miles. The Tributary No. 1 watershed is comprised of mixed land use including single family residential, industrial and agricultural as major components. 3.7.5.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Klein Creek.

Discharge-frequency data for Klein Creek and Klein Creek Tributary No. 2 were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963).


Discharges for the 10-year, 50-year, and 100-year floods for the Klein Creek, Klein Creek Tributary No. 1 and Klein Creek Tributary No. 3 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.

The USGS stream gages used for the hydrologic analyses of the West Branch DuPage River studied in detail are presented in Table WBKC.1 below: Table WBKC.1: USGS Stream Gages Used for Hydrologic Analysis of Klein Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Klein Creek At Carol Stream 05539950 8.81 15

The hydrologic analysis of Klein Creek Tributary No. 3 was directly transferred from the DuPage County FIS (FEMA, 1982). Discharges for the 10-year and 100-year floods of Klein Creek Tributary No. 3 were computed using the log-Pearson Type III method (U.S. Water Resources Council, 1976). Discharges for the 500-year floods of all streams were determined by linear extrapolation of a log-probability graph of flood discharges computed for frequencies up to 100 years. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBKC.2. Table WBKC.2: Klein Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Klein Creek - - d/s of Thunderbird Trail in the Village of Carol Stream 6.37 445 592 655 947 - approximately 1,000 ft


upstream of Dam “A” in Carol Stream 4.90 400 542 619 817 Klein Creek - Tributary No. 1 - at mouth 1.12 33 60 95 240 Klein Creek - Tributary No. 2 - at confluence with Klein Creek 1.22 220 300 355 515 Klein Creek - Tributary No. 3 - at mouth 0.78 140 * 208 * 3.7.5.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Cross-section data for Klein Creek, Klein Creek Tributary No. 2, and Klein Creek Tributary No. 3 were obtained by field measurement. Water-surface elevations of floods of the selected recurrence intervals were computed using the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973) for Klein Creek, Klein Creek Tributary No. 2, and Klein Creek Tributary No. 3. Flood profiles were drawn showing


computed water-surface elevations to an accuracy of 0.5 foot for floods of the selected recurrence intervals.

Table WBKC.3: Klein Creek Manning’s “n” Values

Starting water-surface elevations for Klein Creek, Klein Creek Tributary No. 2, and Klein Creek Tributary No. 3 were calculated using the slope/area method. Roughness coefficients for the hydraulic computations of Klein Creek, Klein Creek Tributary No. 2, and Klein Creek Tributary No. 3 were assigned on the basis of field inspection of floodplain areas. Refer to Table WBKC.3 for further information.



- Klein Creek 0.030 - 0.045 0.060 - 0.080


3.7.5.6 Flood Profiles

- Klein Creek Tributary No. 2 0.035 0.065 - Klein Creek Tributary No. 2 0.055 0.070 3.7.5.4 Flood Boundaries To reference the flood boundaries for Klein Creek, see Map Panels: 0109, 0204, 0205, 0207, 0208, 0403, 0501 and 0502. 3.7.5.5 Floodways


Please reference attached Flood Profile Sheets.


FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Klein Creek (WBKC)WBKC0001 1,956 79 218 4.2 721.5 720.7 720.7 0.01 2

WBKC0002 4,952 490 914 1.0 728.8 728.8 728.8 0.01

WBKC0003 6,795 519 1,524 0.6 735.1 735.1 735.1 0.01

WBKC0004 8,371 121 389 2.3 739.5 739.5 739.5 0.01

WBKC0005 8,849 131 303 3.0 740.3 740.3 740.3 0.01

WBKC0006 9,341 162 791 1.1 743.1 743.1 743.2 0.11

WBKC0007 10,952 40 257 3.5 743.9 743.9 744.0 0.11

WBKC0008 12,521 610 1,757 0.5 746.0 746.0 746.0 0.01

WBKC0009 13,880 250 338 2.7 746.0 746.0 746.0 0.01

WBKC0010 15,618 104 254 2.6 747.2 747.2 747.2 0.01

WBKC0011 17,948 78 262 2.4 748.4 748.4 748.4 0.01

WBKC0012 18,466 575 2,482 0.2 748.6 748.6 748.6 0.01

WBKC0013 20,184 294 5,222 0.1 751.8 751.8 751.8 0.01

WBKC0014 21,590 525 7,852 0.1 751.8 751.8 751.8 0.01

WBKC0015 22,804 294 4,174 0.1 752.9 752.9 753.0 0.11

WBKC0016 24,228 242 3,274 0.2 754.8 754.8 754.9 0.11

WBKC0017 25,727 679 1,442 0.4 755.6 755.6 755.7 0.11

WBKC0018 27,954 288 908 0.4 761.5 761.5 761.5 0.01


AND INCORPORATED AREAS KLEIN CREEK (WBKC)

In feet above confluence with West Branch DuPage River2 Elevation computed without consideration of backwater effect from West Branch DuPage River


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Klein Creek (WBKC)WBKC0019 30,921 65 60 5.4 762.2 762.2 762.2 0.01

WBKC0020 33,209 287 484 0.7 768.5 768.5 768.5 0.01


AND INCORPORATED AREAS KLEIN CREEK (WBKC)

In feet above confluence with West Branch DuPage River2 Elevation computed without consideration of backwater effect from West Branch DuPage River


1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Klein Creek Tributary N0 2 (WBKC)

WBKC0024 131 32 66 5.4 747.3 744.8 744.9 0.11 2

WBKC0025 250 36 81 4.4 747.3 745.4 745.41 2

WBKC0026 1,163 36 95 3.7 748.3 748.3 748.31

WBKC0027 1,365 94 144 2.5 748.8 748.8 748.81

WBKC0028 1,770 33 75 4.7 749.6 749.6 749.7 0.11

WBKC0029 2,133 35 73 4.8 751.6 751.6 751.61

WBKC0030 2,310 46 133 2.7 753.1 753.1 753.11



Klein Creek Tributary NO. 2 (WBKC)

In feet above confluence with East Branch DuPage River2 Elevations without considering backwater effect from Klein Creek

1

TAB

LE 5

700

705

710 710

715 715

720 720

725 725

730 730

735 735

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

161P

WBK

C000

1

WBK

C000

2

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 1

IL P

RAIR

IE P

ATH

FARM

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F


720

725

730 730

735 735

740 740

745 745

750 750

755 755

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

162P

WBK

C000

3

WBK

C000

4

WBK

C000

5

WBK

C000

6

WBK

C000

7

WBK

C000

8

COUN

TY F

ARM

ROA

D

RAIL

ROAD

ST. C

HARL

ES R

OAD

NORT

H AV

ENUE

KUHN

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


720

725

730 730

735 735

740 740

745 745

750 750

755 755

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

163P

WBK

C000

9

WBK

C001

0

WBK

C001

1

WBK

C001

2

THUN

DERB

IRD

TRAI

L

ILLI

NI D

RIVE

DAM

"A"

SPIL

LWAY

NO.

3


500-YEAR FLOOD

500-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F KL

EIN

CREE

K TR

IBUT

ARY

NO. 2

(THU

NDER

BIRD

TRA

IL C

REEK

)

720

725

730 730

735 735

740 740

745 745

750 750

755 755

760 760

765 765

19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

164P

WBK

C001

3

WBK

C001

4

WBK

C001

5

WBK

C001

6

WBK

C001

7

DITC

H CR

OSSI

NG

SPIL

LWAY

NO.

2EL

K TR

AIL

DITC

H CR

OSSI

NG

SPIL

LWAY

NO.

1

LIES

ROA

D

GARY

AVE

NUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

CULVERT

740

745

750 750

755 755

760 760

765 765

770 770

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

165P

WBK

C001

8

WBK

C001

9

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 3RA

ILRO

AD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F

755

760

765 765

770 770

32500 33000 33500 34000 34500 35000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

(WBK

C)

166P

WBK

C002

0SC

HMAL

E RO

AD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


705

710

715 715

720 720

725 725

730 730

735 735

740 740

745 745

750 750

0 500 1000 1500 2000 2500 3000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH KLEIN CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 1 (W

BKC)

167P

WBK

C002

1

CONF

LUEN

CE W

ITH

KLEI

N CR

EEK

COUN

TY F

ARM

ROA

D

CENT

ER A

VENU

E


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

740

745

750 750

755 755

760 760

765 765

785

3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 1 (W

BKC)

168P

WBK

C002

2

WBK

C002

3

WEI

R

WEI

R

PLEA

SANT

HIL

L RO

AD


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY

*DATA NOT AVAILABLE

CULVERTCULVERT

730

735

740 740

745 745

750 750

755 755

760 760

765 765

770 770

775 775

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 2

169P

WBK

C002

4

WBK

C002

5

WBK

C002

6

WBK

C002

7

WBK

C002

8

WBK

C002

9

WBK

C003

0

SEM

INOL

E LA

KE

THUN

DERB

IRD

TRAI

L

BLAC

KHAW

K DR

IVE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE W

ITH

KLEI

N CR

EEK

745

750

755 755

760 760

765 765

770 770

0 500 1000 1500 2000 2500 3000 3500 4000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KLEI

N CR

EEK

TRIB

UTAR

Y NO

. 3 (W

BKC)

170P

WBK

C003

1

WBK

C003

2

WBK

C003

3

CONF

LUEN

CE W

ITH

KLEI

N CR

EEK

GARY

AVE

NUE

OLD

GARY

AVE

NUE

84TH

COU

RT

LIM

IT O

F DE

TAIL

ED S

TUDY

LEGEND500-YEAR FLOOD*100-YEAR FLOOD50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

3.7.6 Kress Creek (WBKR)

Kress Creek is an 18.9-square mile watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to Kress Creek are: West Chicago, St. Charles, Batavia and Unincorporated DuPage County. Much of the upper portions of the watershed are largely open and untouched (Fermi Laboratory and the DuPage Airport), where the central and lower portions of the watershed are a mix of residential, industrial and commercial.

3.7.6.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Kress Creek.


Kress Creek Main Stem origins lie in the West Chicago Prairie Forest Preserve, located north of the Chicago and Northwestern railroad tracks and west of the West Chicago downtown area. The Main Stem of Kress Creek flows south under the Chicago and Northwestern railroad tracks and under Washington Street. On the south side of Washington, the stream changes course to the southwest, passing by the General Mills Factory, and eventually passing under Fenton Lane. On the west side of Fenton, the stream resumes its southerly course and passes under Helena Drive and the Burlington Northern Railroad tracks. The stream again changes bearing to the southeast where it crosses under Town Road and Roosevelt Road. On the south side of Roosevelt Road, the Main Stem of Kress Creek confluences with Kress Creek Unnamed Tributary. Flow continues generally to the southeast, passing under Circle Drive, Joy Road, Joliet Road and Route 59 before confluencing with the West Branch DuPage River. Kress Creek Unnamed Tributary origins lie in Fermi and the DuPage Airport. The respective minor tributaries join in the northern portion of Fermi and proceed to the east, passing under Fermi’s Road “A” and Town Road before confluencing with the Kress Creek Main Stem.

Discharges for the 10-year, 50-year, and 100-year floods for Kress Creek and Unnamed Tributary to Kress Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.


The USGS stream gages used for the hydrologic analyses of the Kress Creek studied in detail are presented in Table WBKR.1 below: Table WBKR.1: USGS Stream Gages Used for Hydrologic Analysis of Kress Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Kress Creek At West Chicago 05540050 10.01 15 Kress Creek is within sub area 6 of the Chicago Metro Study. Peak flows for this sub area, previously derived by the Chicago District, were utilized to derive peak flood flows on Kress Creek and the Unnamed Tributary to Kress Creek. A discharge-frequency relationship was developed for Kress Creek at State Highway 38, and peak flows for Kress Creek at the mouth were obtained by applying the square root of the drainage area ratio. The frequency-discharge drainage area relationships for the streams studied in detail in the community are presented in Table 1, “Summary of Discharges.” The peak discharge for a portion of the headwater area of Kress Creek studied by approximate methods was determined from a regional curve which indicated the 100-year peak discharge as a function of average streambed slope. This curve was determined by solving and plotting solutions to the multiple regression equation adopted by the State of Illinois for several streams within DuPage County (State of Illinois, 1973). A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBKR.2. Table WBKR.2: Kress Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Kress Creek - - mouth at West Branch DuPage River 18.3 760 1,060 1,170 1,470 - at mouth 18.3 760 1,060 1,170 1,470 - at Town Road 14.8 655 915 1,000 1,270 - approximately 1.4 miles d/s of Lies Road 12.3 580 810 890 1,125 - at Roosevelt Road


(State Highway 38) 10.1 510 710 780 985 - at Indian Boundary Rd 5.40 365 510 560 705 - at Hawthorne Lane 4.20 330 460 505 635 - at river mile 7.66 1.46 40 45 52 63 Kress Creek - Unnamed Tributary - at mouth 1.00 95 135 155 195

3.7.6.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Cross-section data for part of Kress Creek and for the entire Unnamed Tributary of Kress Creek were obtained by field measurement. Cross sections for Kress Creek up to Hawthorne Lane are identical to those used for a previous USACE Flood Plain Information Report (USACE, 1975). In addition, channel modifications to Kress Creek for a distance of 600 feet upstream of the Elgin, Joliet, and Eastern Railroad, and culverts at the railroad crossing were inspected in March 1978 and incorporated into the hydraulic model.

Water-surface profiles for Kress Creek, and Unnamed Tributary to Kress Creek were developed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). Starting water-surface elevations for Kress Creek and Unnamed Tributary to Kress Creek were calculated using the slope/area method. Roughness coefficients for the hydraulic computations of Kress Creek and Unnamed Tributary to Kress Creek were assigned on the basis of field inspection of floodplain areas. Refer to Table WBKR.3 for further details. Table WBKR.3: Kress Creek Manning’s “n” Values




- Kress Creek 0.015 - 0.080 0.040 - 0.100 3.7.6.4 Flood Boundaries To reference the flood boundaries for Kress Creek, see Map Panels: 0107, 0108, 0401, 0402, 0404 and 0405. 3.7.6.5 Floodways





FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Kress Creek (WBKR)WBKR0001 882 139 464 2.5 705.5 703.2 703.3 0.11 2

WBKR0002 1,122 150 572 2.0 705.5 704.0 704.1 0.11 2

WBKR0003 3,080 65 231 5.1 709.5 709.5 709.5 0.01

WBKR0004 5,613 95 293 4.0 715.6 715.6 715.7 0.11

WBKR0005 5,782 259 1,312 0.9 720.2 720.2 720.3 0.11

WBKR0006 6,805 250 1,289 0.9 721.3 721.3 721.4 0.11

WBKR0007 7,562 178 2,334 0.5 722.1 722.1 722.2 0.11

WBKR0008 8,006 415 3,128 0.4 722.1 722.1 722.2 0.11 3

WBKR0009 10,324 220 289 1.7 722.2 722.2 722.3 0.11 3

WBKR0010 11,161 330 1,508 0.7 727.2 727.2 727.2 0.01 3

WBKR0011 13,563 151 271 3.7 727.4 727.4 727.4 0.01

WBKR0012 16,205 290 1,076 0.9 734.3 734.3 734.3 0.01

WBKR0013 17,053 521 1,558 0.6 735.7 735.7 735.7 0.01

WBKR0014 18,982 120 557 1.6 737.9 737.9 737.9 0.01

WBKR0015 20,423 125 400 2.2 738.6 738.6 738.7 0.11

WBKR0016 22,175 33 109 2.4 738.7 738.7 738.8 0.11

WBKR0017 23,240 21 64 4.1 738.7 738.7 738.7 0.01

WBKR0018 23,656 30 89 1.6 740.1 740.1 740.1 0.01


AND INCORPORATED AREAS KRESS CREEK (WBKR)



1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Kress Creek (WBKR)WBKR0019 25,234 28 60 1.6 740.7 740.7 740.8 0.11

WBKR0020 25,526 158 150 2.2 744.4 744.4 744.4 0.01 3

WBKR0021 26,351 168 233 1.2 744.9 744.9 745.0 0.11 3

WBKR0022 26,579 166 235 1.0 745.2 745.2 745.3 0.11 3

WBKR0023 27,985 49 133 1.5 745.6 745.6 745.7 0.11

WBKR0024 28,158 81 273 0.7 746.3 746.3 746.4 0.11

WBKR0025 28,722 31 135 1.4 746.3 746.3 746.4 0.11

WBKR0026 28,897 35 212 1.0 748.4 748.4 748.5 0.11

WBKR0027 30,320 39 195 0.7 748.6 748.6 748.7 0.11

WBKR0028 30,482 40 246 0.6 749.8 749.8 749.9 0.11

WBKR0029 32,036 36 193 0.8 749.8 749.8 750.0 0.11

WBKR0030 32,284 40 164 0.9 749.8 749.8 749.8 0.01

WBKR0031 34,078 68 140 0.7 750.0 750.0 750.0 0.01

WBKR0032 34,185 38 116 1.7 750.8 750.8 750.8 0.01

WBKR0033 36,853 24 74 0.6 751.7 751.7 751.7 0.01

WBKR0034 37,424 20 52 0.9 751.7 751.7 751.7 0.01

WBKR0035 41,489 179 529 0.1 755.7 755.7 755.8 0.11

WBKR0036 41,620 222 916 0.1 755.7 755.7 755.8 0.11





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Kress Creek (WBKR)WBKR0037 42,236 161 507 0.1 755.7 755.7 755.8 0.11 3





1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Unnamed Tributary to Kress Creek (WBKR)

WBKR0038 1,303 155 693 0.2 732.6 732.6 732.6 0.01

WBKR0039 2,106 28 56 2.8 732.6 732.6 732.6 0.01

WBKR0040 2,426 200 321 0.5 734.7 734.7 734.7 0.01

WBKR0041 2,649 162 334 0.5 736.7 736.7 736.7 0.01

WBKR0042 3,876 30 37 4.1 741.7 741.7 741.7 0.01

WBKR0043 4,105 77 166 0.9 744.3 744.3 744.3 0.01

WBKR0044 4,850 24 47 2.6 744.6 744.6 744.6 0.01

WBKR0045 5,127 99 221 0.8 749.0 749.0 749.0 0.01

WBKR0046 5,728 67 99 1.3 749.1 749.1 749.1 0.01

WBKR0047 6,118 31 80 1.6 749.2 749.2 749.2 0.01

WBKR0048 6,544 785 189 0.7 749.2 749.2 749.2 0.01

WBKR0049 7,088 5 15 7.9 750.1 750.1 750.1 0.01

WBKR0050 7,560 30 5 1.4 751.9 751.9 751.9 0.01

WBKR0051 8,001 125 183 0.7 752.5 752.5 752.5 0.01

WBKR0052 8,591 45 93 0.9 752.9 752.9 752.9 0.01

WBKR0053 9,124 300 985 0.1 757.0 757.0 757.0 0.01

WBKR0054 11,762 163 579 0.1 757.0 757.0 757.0 0.01


AND INCORPORATED AREAS UNNAMED TRIBUTARY TO KRESS CREEK (WBKR)

In feet above confluence with Kress Creek1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Unnamed Tributary to Kress Creek (WBKR)

WBKR0055 11,950 35 122 0.7 758.6 758.6 758.6 0.01


AND INCORPORATED AREAS UNNAMED TRIBUTARY TO KRESS CREEK (WBKR)

In feet above confluence with Kress Creek1

TAB

LE 5

685

690

695 695

700 700

705 705

710 710

715 715

720 720

725 725

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

171P

WBK

R000

1

WBK

R000

2

WBK

R000

3

WBK

R000

4

WBK

R000

5

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

STAT

E RO

UTE

59

JOLI

ET S

TREE

T

FOOT

BRID

GE

JOY

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



700

705

710 710

715 715

720 720

725 725

730 730

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

172P

WBK

R000

6

WBK

R000

7

WBK

R000

8

WBK

R000

9

WBK

R001

0

MAY

STR

EET

RAIL

ROAD

FOOT

BRID

GE

UNNA

MED

TRI

BUTA

RY T

O KR

ESS

CREE

K

TOW

N RO

AD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE O

F

KRES

S CR

EEK

(WBK

R)

710

715

720 720

725 725

730 730

735 735

740 740

745 745

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

173P

WBK

R001

1

WBK

R001

2

WBK

R001

3

WBK

R001

4

ROAD

A

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


720

725

730 730

735 735

740 740

745 745

750 750

755 755

19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

174P

WBK

R001

5

WBK

R001

6

WBK

R001

7

WBK

R001

8

WBK

R001

9

WBK

R002

0

FABY

AN P

ARKW

AY

MCC

HESN

EY R

OAD

FOOT

BRID

GE

ROOS

EVEL

T RO

AD

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE UPSTREAM OF FOOTBRIDGE

720

725

730 730

735 735

740 740

745 745

750 750

755 755

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

175P

WBK

R002

1

WBK

R002

2

WBK

R002

3

WBK

R002

4

WBK

R002

5

WBK

R002

6

WBK

R002

7

WBK

R002

8

WBK

R002

9

WBK

R003

0

DOW

NS D

RIVE

WES

TERN

DRI

VE

INDI

AN B

OUND

ARY

ROAD

RAIL

ROAD

SPU

R

INDU

STRI

AL D

RIVE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

730

735

740 740

745 745

750 750

755 755

32500 33000 33500 34000 34500 35000 35500 36000 36500 37000 37500 38000 38500 39000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

176P

WBK

R003

1

WBK

R003

2

WBK

R003

3

WBK

R003

4

HAW

THOR

NE L

ANE

RAIL

ROAD

SPU

R

HARV

ESTE

R RO

AD

RAIL

ROAD

SPU

R


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


* DATA NOT AVAILABLE DOWNSTREAM OF APPROXIMATELY

DUPAGE RIVER37,500 FT ABOVE CONFLUENCE WITH WEST BRANCH

730

735

740 740

745 745

750 750

755 755

760 760

39000 39500 40000 40500 41000 41500 42000 42500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

KRES

S CR

EEK

(WBK

R)

177P

WBK

R003

5

WBK

R003

6

WBK

R003

7

UNNA

MED

DRI

VECR

OWN

COUR

T

POW

IS R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


710

715

720 720

725 725

730 730

735 735

740 740

745 745

750 750

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH KRESS CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

TRI

BUTA

RY T

O KR

ESS

CREE

K (W

BKR)

178P

WBK

R003

8

WBK

R003

9

WBK

R004

0

WBK

R004

1

WBK

R004

2

WBK

R004

3

WBK

R004

4

WBK

R004

5

WBK

R004

6

WBK

R004

7

CONF

LUEN

CE W

ITH

KRES

S CR

EEK

ROOS

EVEL

T RO

AD

PARK

ING

LOT

BRID

GE

TOW

N RO

AD

PRIV

ATE

ROAD

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


100-YEAR BACKWATER FROM KRESS CREEK

THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR PROFILE TO

BE SHOWN SEPARATELY

735

740

745 745

750 750

755 755

760 760

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)

STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH KRESS CREEK

FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

UNNA

MED

TRI

BUTA

RY T

O KR

ESS

CREE

K (W

BKR)

179P

WBK

R004

8

WBK

R004

9

WBK

R005

0

WBK

R005

1

WBK

R005

2

WBK

R005

3

WBK

R005

4

WBK

R005

5

INDU

STRI

AL D

RIVE

INDU

STRI

AL D

RIVE

GENE

VA R

OAD

RAIL

ROAD

RAIL

ROAD

RAIL

ROAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


CULVERT

* DATA NOT AVAILABLE UPSTREAM OF RAILROAD CULVERT

3.7.7 Springbrook No. 1 (WBSP)

3.7.7.1 Tributary Description Springbrook No. 1 is a 4921-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to Springbrook No. 1 are Wheaton, Glen Ellyn, Warrenville and Unincorporated DuPage County. Much of the land use in the upper and central portions of Springbrook No. 1 watershed is developed as single and multi-family residential, with a few pockets of commercial activity on Roosevelt Road. The lower sections of the watershed are primarily kept in open space.

Springbrook No. 1 is greatly storm-sewered in the upper reaches of the watershed. Flow consistently bears to the southwest through the downtown area of Wheaton, crossing the Chicago and Northwestern Railroad tracks and Roosevelt Road. It is on the southern side of Roosevelt Road that Springbrook No. 1 opens up to steep-sloped channels. Flow proceeds to the southwest, passing under such residential roads as Park Avenue, Elm Street, Warrenville Road, the Illinois Prairie Path, Gables Boulevard, Aurora Way, Creekside Drive, Stonebridge Terrace, Shaffner Road, Essex Road and Center Avenue. Downstream of this point, the land use for Springbrook No.1 abruptly changes from residentially developed to open agricultural land. The creek proceeds to the west, passes under Winfield Road, and enters the Blackwell Forest Preserve. Within the Forest Preserve, Springbrook No. 1 bears to the southwest and confluences with the West Branch DuPage River just north of the intersection of the Illinois Prairie Path and Batavia Road.


Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Springbrook No.1.

Discharges for the 10-year, 50-year, and 100-year floods for Springbrook No. 1 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.

The USGS stream gages used for the hydrologic analyses of the Springbrook No. 1 studied in detail are presented in Table WBSP.1 below: Table WBSP.1: USGS Stream Gages Used for Hydrologic Analysis of Springbrook No. 1


USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Springbrook No. 1 Near Warrenville 05540090 6.01 15 A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBSP.2. Table WBSP.2: Springbrook No. 1 Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Springbrook No. 1 - - mouth at West Branch DuPage River 7.10 495 685 795 1,140 - at mile 2.917 3.30 350 480 555 800 - at Aurora Way 2.78 305 425 490 705 - at Warrenville Road 2.10 265 370 430 615 3.7.7.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles.


The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBSP.3 for further information regarding roughness coefficients. Table WBSP.3: Springbrook No. 1 Manning’s “n” Values


Stream Overbank "n" Channel "n"

- Springbrook No.1 0.035 - 0.055 0.070 - 0.100 3.7.7.4 Flood Boundaries



To reference the flood boundaries for Springbrook No.1 Tributary, see Map Panels: 0406, 0408, 0409, 0502, 0504, 0505, 0507 and 0508. 3.7.7.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Spring Brook No. 1 (WBSP)

WBSP0001 454 190 376 2.2 697.7 693.8 693.9 0.11 2

WBSP0002 2,188 226 765 1.0 700.1 700.1 700.2 0.11

WBSP0003 4,685 184 335 2.4 707.3 707.3 707.3 0.01

WBSP0004 8,264 122 570 1.3 711.2 711.2 711.3 0.11

WBSP0005 11,209 248 482 1.5 714.1 714.1 714.2 0.11

WBSP0006 12,521 120 363 2.0 716.8 716.8 716.9 0.11

WBSP0007 14,528 194 597 1.1 720.1 720.1 720.2 0.11

WBSP0008 15,242 305 897 0.8 720.5 720.5 720.6 0.11

WBSP0009 15,736 96 496 1.1 722.4 722.4 722.5 0.11

WBSP0010 16,944 205 1,539 0.4 723.0 722.9 723.0 0.11 3

WBSP0011 17,974 292 1,466 0.4 723.5 723.5 723.6 0.11

WBSP0012 18,121 432 1,205 0.5 723.6 723.6 723.7 0.11

WBSP0013 18,506 466 1,479 0.4 723.6 723.6 723.7 0.11

WBSP0014 19,445 211 2,237 0.2 723.7 723.7 723.8 0.11

WBSP0015 20,118 118 777 0.7 723.7 723.7 723.8 0.11

WBSP0016 20,724 156 1,271 0.4 723.8 723.8 723.9 0.11

WBSP0017 21,606 64 225 2.4 723.9 723.9 724.0 0.11


AND INCORPORATED AREAS SPRING BROOK NO. 1 (WBSP)



1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Spring Brook No. 1 (WBSP)

WBSP0018 22,037 178 520 1.1 724.2 724.2 724.3 0.11

WBSP0019 23,084 200 296 1.7 725.3 725.3 725.4 0.11

WBSP0020 24,180 100 228 2.1 725.9 725.9 726.0 0.11

WBSP0021 25,600 31 140 3.5 727.4 727.4 727.4 0.01

WBSP0022 25,871 40 177 2.8 727.7 727.7 727.8 0.11

WBSP0023 30,514 47 301 1.4 731.1 731.1 731.2 0.11


AND INCORPORATED AREAS SPRING BROOK NO. 1 (WBSP)



1

TAB

LE 5

675

680

685 685

690 690

695 695

700 700

705 705

710 710

715

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

1 (W

BSP)

180P

WBS

P000

1

WBS

P000

2

WBS

P000

3

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

MOR

RIS

COUR

T RO

AD

PAM

ELA

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



690

695

700 700

705 705

710 710

715 715

720 720

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

1 (W

BSP)

181P

WBS

P000

4

WBS

P000

5

WBS

P000

6

WIN

FIEL

D RO

AD

UNNA

MED

ROA

D

UNNA

MED

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


700

705

710 710

715 715

720 720

725 725

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

1 (W

BSP)

182P

WBS

P000

7

WBS

P000

8

WBS

P000

9

WBS

P001

0

WBS

P001

1

WBS

P001

2

WBS

P001

3

WBS

P001

4

ESSE

X RO

AD

FOOT

BRID

GE

SEW

AGE

PLAN

T BR

IDGE

SEW

AGE

PLAN

T BR

IDGE

SEW

AGE

PLAN

T BR

IDGE

W. C

REEK

SIDE

DRI

VE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


700

705

710 710

715 715

720 720

725 725

730 730

735 735

740 740

19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

1 (W

BSP)

183P

WBS

P001

5

WBS

P001

6

WBS

P001

7

WBS

P001

8

WBS

P001

9

WBS

P002

0

WBS

P002

1

WBS

P002

2

STON

EBRI

DGE

TRAI

L

CREE

KSID

E DR

IVE

FOOT

BRID

GE

W. A

UROR

A W

AY

S. G

ABLE

S BO

ULEV

ARD

PRAI

RIE

PATH


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


705

710

715 715

720 720

725 725

730 730

735 735

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

SPRI

NG B

ROOK

NO.

1 (W

BSP)

184PW

BSP0

023

WAR

RENV

ILLE

ROA

D

HAW

THOR

NE L

ANE

LIM

IT O

F FL

OODW

AY E. E

LM S

TREE

TLI

MIT

OF

DETA

ILED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.7.8 Steeple Run Tributary (WBSR)


Steeple Run Tributary is a 1754-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to Steeple Run Tributary are Naperville, Lisle and Unincorporated DuPage County. The primary land use within the Steeple Run watershed is single-family residential.

Steeple Run has several feeder tributaries that branch off in all directions in the upper portions of the watershed. There is a general conglomeration of the tributaries at May Watts Park, found south of North Street, west of Charles Drive and east of Harrison Street in the City of Naperville. Flow proceeds to the south passing under Benton Avenue, Chicago Avenue and Julian Street at the intersection of Julian and Porter Streets. The tributary enters a large conduit that travels west under Porter Street. The stream enters the grounds at North Central College and joins with the West Branch DuPage River north of Hillside Avenue. 3.7.8.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Steeple Run Tributary.

Discharge-frequency data for West Branch DuPage River were developed through the use of the Chicago Metropolitan Study, DuPage River Basin performed by the USACE’s Hydrologic Engineering Center (USACE, 1974). In the Chicago study, the DuPage River Basin above Shorewood, Illinois, was divided into 20 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). Using 24-hour rainfall data obtained from Weather Bureau Technical Paper No. 40, one-hour values, in critical order, were entered into the HEC-1 model of the DuPage River Basin to determine the 10-year, 50-year, and 100-year peak discharges (U.S. Department of Commerce, 1963). 3.7.8.3 Hydraulic Analysis Analyses of the hydraulic characteristics of flooding from the West Branch DuPage River were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Users should be aware that flood elevations shown on the FIRM represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. For construction and/or floodplain


management purposes, users are encouraged to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. Cross-section data for West Branch DuPage River were obtained by field measurement.

The 100-year water-surface elevation on the West Branch DuPage River was computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, 1976). Since no formal FEMA study was completed on Steeple Run Tributary, the West Branch DuPage River 100-yr elevation information, determined through the above methods, at the location of the junction between the West Branch DuPage River and Steeple Run Tributary is used for backwater effects on Steeple Run Tributary. In addition to the determined backwater zone information, the unnumbered A-zone boundary was further formed through local studies and the USGS Flood of Record Maps.

3.7.8.4 Flood Boundaries To reference the flood boundaries for Steeple Run Tributary, see Map Panels: 0801, 0802, 0804 and 0805. 3.7.8.5 Floodways

No floodway information is available for this tributary


No flood profiles are available for this tributary.


3.7.9 West Branch Tributary No. 1 (WBW1)

3.7.9.1 Tributary Description The West Branch Tributary No. 1 watershed covers approximately 2.7 square miles. The West Branch Tributary No.1 drainage system consists of West Branch Tributary No. 1 to the West Branch of the DuPage River (West Branch Tributary No. 1 Main Stem) with five tributaries to the West Branch Tributary No. 1 Main Stem. Most of the watershed is unincorporated, although portions are incorporated into Bloomingdale to the south, and Hanover Park and Roselle to the north. The watershed boundary in general extends from Lake Street in the north, to roughly Schick Road in the south, to the West Branch of the DuPage River to the west. The western portion of the watershed is primarily contained in the Mallard Lake Forest Preserve. The eastern portion of the watershed is mainly residential. The West Branch Tributary No.1 Main Stem begins southeast of the intersection of Argyle and Wheaton Roads in the unincorporated area of DuPage County commonly referred to as Keeneyville. Flow proceeds to the northwest passing under such roads as Wheaton Road, Papworth Street, Argyle Avenue, Keeney Road, Virginia Road, Gary Avenue, and Cloverdale Road. On the west side of Cloverdale Road, West Branch Tributary No. 1 Main Stem enters the Mallard Lake Forest Preserve. Flow from the Main Stem bears to the southwest, eventually converging with a secondary branch in the Forest Preserve. The Tributary the proceeds to the north, encountering and joining the West Branch DuPage River in the north section of Mallard Lake Forest Preserve. 3.7.9.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 1.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW1.1.

Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 1 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.

Table WBW1.1: West Branch Tributary No. 1 Summary of Discharges


Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr West Branch - Tributary No. 1 - just upstream of Forest Preserve Road 1.41 65 140 190 305 3.7.9.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill


Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBW1.2 for further information regarding roughness coefficients.

Table WBW1.2: West Branch Tributary No. 1 Manning’s “n” ValuesManning’s “n” Values


- West Branch Tributary No. 1 0.050 - 0.080 0.095 3.7.9.4 Flood Boundaries

To reference the flood boundaries for West Branch Tributary No. 1, see Map Panels: 0103, 0106, 0201, 0202, 0204 and 0205. 3.7.9.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


West Branch Tributary No. 1 (WBW1)

WBW10001 6,000 300 1,859 0.1 768.7 768.7 768.8 0.11 2

WBW10002 9,010 228 710 0.3 770.8 770.9 770.9 0.11

WBW10003 10,390 93 349 0.5 771.7 771.8 771.8 0.11 3


AND INCORPORATED AREAS WEST BRANCH TRIBUTARY NO. 1 (WBW1)

In feet above confluence with West Branch DuPage River2 Elevation computed without consideration of backwater effects from West Branch DuPage River


1

TAB

LE 5

758

760

762 762

764 764

766 766

768 768

770 770

772 772

5800 6000 6200 6400 6600 6800 7000 7200 7400 7600 7800 8000 8200 8400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 1

(WBW

1)

197P

WBW

1000

1

FORE

ST P

RESE

RVE

ROAD

FOOT

BRID

GE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



LIM

IT O

F DE

TAIL

ED S

TUDY

760

762

764 764

766 766

768 768

770 770

772 772

774 774

8400 8600 8800 9000 9200 9400 9600 9800 10000 10200 10400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 1

(WBW

1)

198P

WBW

1000

2

WBW

1000

3

CLOV

ERDA

LE R

OAD

GARY

AVE

NUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



3.7.10.1 Tributary Description West Branch Tributary No. 2 is a 3004-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to West Branch Tributary No. 2, within DuPage County, are Hanover Park, Bartlett and Unincorporated DuPage County. The overall land use within the upper reaches of the watershed (Cook County) is urbanized development with large stretches of commercial and residential zones. The central part of the watershed, located in DuPage County, is primarily residential. The lower sections of the watershed are Forest Preserve open prairie lands. West Branch Tributary No. 2 begins in Cook County Illinois just north of Bartlett. Flow proceeds directly south, entering DuPage County just west of Hillandale Drive in Bartlett. Flow continues to the south passing under such roads as Amherst Drive, Wilcox Drive, Country Drive, Brookside Drive, Francine Drive, and Stearns Road. On the south side of Stearns Road, the West Branch Tributary No. 2 enters the Hawk Hollow Forest Preserve, and joins the West Branch DuPage River. 3.7.10.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 2. Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 2 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW2.1.

Table WBW2.1: West Branch Tributary No. 2 Summary of Discharges Summary of Discharges

Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr West Branch - Tributary No. 2


- at mouth 3.70 278 390 430 569 3.7.10.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.

The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE,

Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles.

HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment.


Refer to Table WBW2.2 for further information regarding roughness coefficients.



- West Branch Tributary No. 2 0.015 - 0.035 0.035 - 0.120

3.7.10.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No.2, see Map Panels: 0102 and 0103. 3.7.10.5 Floodways






FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


West Branch Tributary No. 2 (Country Creek) (WBW2)

WBW20001 2,783 32 63 6.8 754.4 754.4 754.5 0.11

WBW20002 6,570 283 331 1.2 771.3 771.3 771.4 0.11

WBW20003 7,010 263 1,295 0.3 771.4 771.4 771.5 0.11

WBW20004 7,775 104 258 1.7 773.4 773.4 773.4 0.01

WBW20005 11,120 84 317 0.9 781.8 781.8 781.8 0.01


AND INCORPORATED AREAS WEST BRANCH TRIBUTARY NO. 2 (COUNTRY CREEK) (WBW2)


TAB

LE 5

730

735

740 740

745 745

750 750

755 755

760 760

765 765

770 770

775 775

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 2

(COU

NTRY

CRE

EK) (

WBW

2)

199P

WBW

2000

1

STEA

RNS

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R


750

755

760 760

765 765

770 770

775 775

780 780

785 785

790 790

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 2

(COU

NTRY

CRE

EK) (

WBW

2)

200P

WBW

2000

2

WBW

2000

3

WBW

2000

4

WBW

2000

5

FRAN

CINE

DRI

VE

BROO

KSID

E DR

IVE

WES

T CO

UNTR

Y DR

IVE

FOOT

BRID

GE

FOOT

BRID

GE

DEVO

N AV

ENUE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


THE 50-YEAR PROFILE IS TOO CLOSETO THE 100-YEAR PROFILE TO

BE SHOWN SEPARATELY




West Branch Tributary No. 3 is a 1081-acre watershed that is tributary to the West Branch DuPage River. Communities that contribute watershed area to West Branch Tributary No. 3 are West Chicago and Unincorporated DuPage County. The overall land use for this watershed is large-parceled residential. West Branch Tributary No. 3 begins on the west side of Waynewood Drive, just south of North Avenue and east of Route 59. Flow proceeds to the east, passing under Waynewood Drive, the Illinois Prairie Path and Prince Crossing Road. On the east side of Prince Crossing, the West Branch Tributary No. 3 enters the Timber Ridge Forest Preserve and confluences with the West Branch DuPage River. 3.7.11.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 3. Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 3 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW3.1.

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr West Branch - Tributary No. 3 - at mouth 1.32 190 335 430 650 3.7.11.3 Hydraulic Analysis


Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles. The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles.

Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBW3.2 for further information regarding roughness coefficients.




- West Branch Tributary No. 3 0.040 - 0.070 0.085 3.7.11.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No.3, see Map Panels: 0108, 0109, 0402 and 0403.

3.7.11.5 Floodways






FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBW30001 1,858 224 382 1.1 726.1 725.9 726.0 0.11 2

WBW30002 3,086 175 601 0.7 732.9 732.9 733.0 0.11

WBW30003 3,560 110 785 0.6 734.8 734.8 734.8 0.01

WBW30004 4,922 400 2,041 0.2 734.8 734.8 734.8 0.01

WBW30005 6,464 57 126 3.7 738.2 738.2 738.2 0.01

WBW30006 7,684 17 70 3.8 750.0 750.0 750.1 0.11

WBW30007 8,080 193 377 3.7 750.9 750.9 751.0 0.11



In feet above confluence with West Branch DuPage River2 Elevation computed without considering backwater effects from West Branch DuPage River

1

TAB

LE 5

705

710

715 715

720 720

725 725

730 730

735 735

740 740

745 745

750 750

0 400 800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 3

(WBW

3)

201P

WBW

3000

1

WBW

3000

2

WBW

3000

3

WBW

3000

4

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

PRIN

CE C

ROSS

ING

ROAD

RAIL

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



715

720

725 725

730 730

735 735

740 740

745 745

750 750

755 755

5200 5600 6000 6400 6800 7200 7600 8000 8400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 3

(WBW

3)

202P

WBW

3000

5

WBW

3000

6

WBW

3000

7

FOOT

BRID

GE

WAY

NEW

OOD

DRIV

E


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


LIM

IT O

F DE

TAIL

ED S

TUDY


3.7.12.1 Tributary Description The West Branch Tributary No. 4 watershed is located in central DuPage County and drains approximately 2.86 square miles of area within the Village of Carol Stream and Unincorporated DuPage County where it meets with the West Branch of the DuPage River. At the headwaters of the watershed there is no defined channel, the watercourse generally consists of detention ponds and connecting storm sewers, and, in general, the flow is from north to south. Approximately two-thirds of the watershed is within the corporate limits of the Village of Carol Stream while the balance is in Unincorporated DuPage County.

Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 4 were computed using the log-Pearson Type III method

The open-channel system of West Branch Tributary No. 4 is approximately 1.9 miles long, and has an average bed slope of 0.2 percent. It meets with the West Branch of the DuPage River in the Timber Ridge Forest Preserve. Between the confluence and North Avenue there exists Forest Preserve property, undeveloped private property, and a 32.6-acre Oak Creek Estates development of non-storm-sewered 1 acre (approximately) lots of septic fields. The only bridge or culvert in this reach is the Chicago Northwestern Railroad crossing. Between North Avenue and St. Charles Road are the Sidwell Corporation grounds, which include two small on-site water treatment ponds, which discharge into the stream. North of St. Charles Road is Benjamin School and Treetops, an approximately 37 acre residential property that includes a lake and a small non-native animal community within its confines. The north property limit of Treetops is 650 +/- feet south of Timber Lane. Between this property boundary and the corporate limits of the Village of Carol Stream is the Wayne Oaks Lake/Dam and a subdivision called Branigar’s 1st Addition to Wayne Oaks (Wayne Oaks Subdivision). Along the channel, and between the corporate limits and Evergreen Drive is Dogwood Park, a grassland area currently owned by the Village of Carol Stream. North of Evergreen Drive are the Village of Carol Stream residential homes where there is no longer a defined open channel, and West Branch Tributary No. 4 essentially consists of on-and off-line reservoir/detention facilities interconnected by storm sewers. At the headwaters of the watershed, at Army Trail Road, there is the Heritage Plaza commercial center. 3.7.12.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 4.


(U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW4.1. Table WBW4.1: West Branch Tributary No. 4 Summary of Discharges


Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.

Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry


The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model


was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBW4.2 for further information regarding roughness coefficients.



- West Branch

3.7.12.4 Flood Boundaries

3.7.12.5 Floodways

Tributary No. 4 0.065 0.085 - 0.100

To reference the flood boundaries for West Branch Tributary No. 4, see Map Panels: 0106, 0109, 0204 and 0207.

No floodway information is currently available for this tributary. 3.7.12.6 Flood Profiles Please reference attached Flood Profile Sheets.


705

710

715 715

720 720

725 725

730 730

735 735

740 740

745 745

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 4

(WBW

4)

203P

WBW

4000

1

WBW

4000

2

WBW

4000

3

WBW

4000

4

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

RAIL

ROAD

NORT

H AV

ENUE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



720

725

730 730

735 735

740 740

745 745

6500 7000 7500 8000 8500 9000 9500 10000 10500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 4

(WBW

4)

204P

WBW

4000

5

WBW

4000

6

ST. C

HARL

ES R

OAD

TIM

BER

LANE

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED




West Branch Tributary No. 5 is a 1071-acre watershed that is tributary to the West Branch DuPage River. Communities that contribute watershed area to West Branch Tributary No. 5 are West Chicago, Winfield and Unincorporated DuPage County. The primary land use in the western half of the watershed is single-family residential, where the eastern half is untouched forested areas.

West Branch Tributary No. 5 origins can be found in the Timber Ridge Forest Preserve north of Geneva Road and east of Prince Crossing Road. Flow proceeds to the southeast, through the Forest Preserve, and at the intersection of Indian Knoll and Geneva, the creek crosses Geneva Road. The stream continues a parallel course to Indian Knoll Road on the west side, crosses Indian Knoll at the intersection of Main and Indian Knoll, and enters Winfield Mounds Forest Preserve. West Branch Tributary No. 5 bears directly south through the heart of the Forest Preserve, crosses Highlake Road, turns to the southwest and joins the West Branch DuPage River near the dead-end section of Morningside Drive.


Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 5.

Discharges for the 10-year, 50-year, and 100-year floods West Branch Tributary No. 5 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW5.1. Table WBW5.1: West Branch Tributary No. 5 Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr West Branch - Tributary No. 5


- at mouth 0.07 35 * 95 * 3.7.13.3 Hydraulic Analysis

Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals.

Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry

Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.


The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment.


Refer to Table WBW5.2 for further information regarding roughness coefficients.



- West Branch Tributary No. 5 0.050 - 0.070 0.065 - 0.085

3.7.13.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No. 5, see Map Panels: 0402, 0403 and 0406. 3.7.13.5 Floodways

No floodway information is currently available for this tributary.



695

700

705 705

710 710

715 715

720 720

725 725

0 250 500 750 1000 1250 1500 1750 2000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 5

(WBW

5)

205P

WBW

5000

1

WBW

5000

2

WBW

5000

3

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

LEST

ER S

TREE

T

BOLL

ES A

VENU

E

DONA

LD A

VENU

E

CHIC

AGO

AND

NORT

H W

ESTE

RN R

AILR

OAD

LIM

IT O

F D

ETAI

LED

STUD

Y


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED



*DATA NOT AVAILABLE



West Branch Tributary No. 6 is a 771-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to West Branch Tributary No. 6 are Naperville, Lisle and Unincorporated DuPage County. The overall land use for this watershed is single-family residential.

West Branch Tributary No. 6 lies entirely within a large subdivision and as a result much open channel has been converted to conduit. Flow in the watershed starts in the Village of Lisle on the west side of College Road, north and proceeds to the southwest. The tributary then enter the City of Naperville still flowing in a southwesterly direction, opening up to open channel on the downstream side of Johnson Drive. The stream proceeds under Olesen Drive, Hobson Mill Drive (twice) and enters Pioneer Park Forest Preserve where it confluences with the West Branch DuPage River.


Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 6. Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 6 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW6.1. Table WBW6.1: West Branch Tributary No. 6 Summary of Discharges



Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.

The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE,


HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBW6.2 for further information regarding roughness coefficients.




- West Branch Tributary No. 6 0.070 0.100 3.7.14.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No. 6, see Map Panels: 0804, 0805 and 0807. 3.7.14.5 Floodways






FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBW60001 1,294 23 61 4.6 667.0 667.0 667.1 0.11

WBW60002 2,733 266 335 0.8 684.8 684.8 684.9 0.11 2




1

TAB

LE 5

635

640

645 645

650 650

655 655

660 660

665 665

670 670

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 6

(WBW

6)

206P

WBW

6000

1

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

HOBS

ON M

ILL

DRIV

E (W

EST)


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



655

660

665 665

670 670

675 675

680 680

685 685

1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 6

(WBW

6)

207P

HOBS

ON M

ILL

DRIV

E (E

AST)


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


665

670

675 675

680 680

685 685

690 690

2400 2500 2600 2700 2800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 6

(WBW

6)

208P

WBW

6000

2

UNNA

MED

ROA

D

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



3.7.15.1 Tributary Description West Branch Tributary No. 7 is a 375-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to West Branch Tributary No. 7 are Naperville, Lisle and Unincorporated DuPage County. The overall land use for this watershed is single-family residential.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBW7.1.

This short tributary begins on the south side of Hobson Road. Flow proceeds to the west passing underneath Market Avenue and Hobson Oaks Drive into the Goodrich Woods Forest Preserve. Upon leaving the Forest Preserve, West Branch Tributary No.7 passes under Oxford Lane and confluences with the West Branch DuPage River at the northeast corner of Washington Street and 75th Street. 3.7.15.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for West Branch Tributary No. 7.

Discharges for the 10-year, 50-year, and 100-year floods for West Branch Tributary No. 7 were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation.




Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals.

Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Starting water-surface elevations for the streams studied in detail and limited detail were determined using corresponding flood elevations on the main stem, flood profiles from previous studies by the State of Illinois and the SCS (State of Illinois, 1975; and Des Plaines River Watershed Steering Committee, January 1976), normal depth computations, and rating curves. Backwater effects at confluences with larger stream systems are reflected on the flood profiles.

The water-surface elevations for the streams studied in detail and limited detail were computed using either the SCS WSP-2 backwater computer program or the USACE HEC-2 step-backwater computer program (U.S. Department of Agriculture, 1974; USACE, HEC-2 Water-Surface Profiles, Computer Program723-X6-L202A, 1973). The USACE HEC-2 model was used for all streams studied in detail and limited detail except for Meacham Creek, Sawmill Creek, Salt Creek, Spring Brook, and Westwood Creek, which were modeled utilizing the SCS WSP-2 program (U.S. Department of Agriculture, 1974). Flood profiles were drawn showing computed water-surface elevations for floods of the selected recurrence intervals. Streams studied in detail have flood profiles drawn for the 500-year, 100-year, 50-year, and 10-year storm events, with the exception of Upper Salt Creek, Klein Creek Tributary No. 1, Klein Creek Tributary No. 2, Sawmill Creek, Sawmill Creek Tributary No. 1, Wards Creek, West Branch Tributary No. 5, West Branch Tributary No. 7, East Branch Tributary No. 1, and East Branch Tributary No. 2, which have only the 10-year and 100-year profiles. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBW7.2 for further information regarding roughness coefficients.




- West Branch Tributary No. 7 0.050 - 0.060 0.065 - 0.100 3.7.15.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No. 7, see Map Panels: 0804, 0805, 0807 and 0808. 3.7.15.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY



WBW70001 1,793 674.51 3 3 3 3 3 3

WBW70002 3,361 683.32 1 3 3 3 3 3 3



In feet above confluence with West Branch DuPage River2 Cross-section is shown on FIRM; not on profile

3 Data not available

1

TAB

LE 1

635

640

645 645

650 650

655 655

660 660

665 665

670 670

675 675

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 7

(WBW

7)

209P

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

UNNA

MED

ROA

D


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED



*DATA NOT AVAILABLE

655

660

665 665

670 670

675 675

680 680

685 685

1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 7

(WBW

7)

210P

WBW

7000

1

UNNA

MED

ROA

D

OXFO

RD L

ANE


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE

655

660

665 665

670 670

675 675

680 680

685 685

2600 2700 2800 2900 3000 3100 3200 3300 3400 3500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WES

T BR

ANCH

TRI

BUTA

RY N

O. 7

(WBW

7)

211P

WBW

7000

2LI

MIT

OF

DETA

ILED

STU

DY


100-YEAR FLOOD

50-YEAR FLOOD*

10-YEAR FLOOD

STREAM BED


*DATA NOT AVAILABLE


3.7.16.1 Tributary Description West Branch Tributary No. 8 is a 494-acre watershed that is tributary to the West Branch DuPage River. The communities that contribute watershed area to West Branch Tributary No. 8 are Naperville and Unincorporated DuPage County. The overall land use for this watershed is single-family residential. This short tributary has two principal branches which join just upstream of Knoch Knolls Road in the Knoch Knolls Commons area of Naperville. The main stem then has a short run of about 800 feet before joining the West Branch DuPage River. Both of the principal branches and almost the entirety of the watershed are within Will County. The portion of the northern branch that once reached into DuPage County was pirated into the South of Foxcroft Tributary, just west of Petworth Court in Will County, when residential development took place. This change effectively cut off this watershed from DuPage County stormwater management concerns. 3.7.16.2 Hydrologic Analysis There is no information regarding the regulatory hydrologics of West Branch Tributary No. 8 within the confines of DuPage County. 3.7.16.3 Hydraulic Analysis There is no information regarding the regulatory hydraulics of West Branch Tributary No. 8 within the confines of DuPage County. 3.7.16.4 Flood Boundaries To reference the flood boundaries for West Branch Tributary No. 8, see Map Panels: 0709 and 0807. 3.7.16.5 Floodways No floodway information is currently available for this tributary. 3.7.16.6 Flood Profiles No flood profile information is currently available for this tributary.

Section printed 26 May 2004

3.7.17 Winfield Creek (WBWF)

Winfield Creek is one of the larger tributary watersheds to the West Branch of the DuPage River, located to the east of the West Branch and approximately midway between where the West Branch enters and leaves DuPage County. The headwaters of the Winfield Creek watershed include areas of the Village of Glendale Heights to the north, the Village of Glen Ellyn to the south, and Unincorporated DuPage County between the two communities. There is no defined channel in any of these two communities. The watercourse consists of detention ponds and natural depressional areas connected by storm sewers. The flow is generally from north to south within the Village of Glendale Heights and from south to north within the Village of Glen Ellyn. Thereafter, Winfield Creek flows from northeast to southwest through the Village of Carol Stream and the City of Wheaton. Within the Village of Winfield, the flow is north to south up to East Street, and then from east to west until the confluence with the West Branch.

3.7.17.1 Tributary Description The Winfield Creek watershed is located in central DuPage County and drains approximately 8.3 square miles of area within the Villages of Winfield, Carol Stream, Glen Ellyn, Glendale Heights, the City of Wheaton, and Unincorporated DuPage County. Winfield Creek meets with the West Branch of the DuPage River at the western corporate limits of the Village of Winfield between Beecher Avenue and Washington Avenue. The watershed consists of residential development, commercial areas, industrial parks, recreational community parks, undeveloped lots, a golf course (Cantigny Golf Club), and a Forest Preserve (Belleau Woods). The building structures within and adjacent to the floodplain are over 95% residential while the balance is business, or maintenance storage structures. There are three main parks within the floodplain of Winfield Creek which have been designated as part of the DuPage County wetland mitigation banking program – Lincoln Marsh, Northside Park, and Community Park. Lincoln Marsh is owned and maintained by the Wheaton Park District; Lincoln Marsh is jointly owned by the DuPage County Forest Preserve District and the Wheaton Park District, and maintained by the Wheaton Park District; and Community Park is owned by the Village of Carol Stream and maintained by the Wheaton Park District. A fourth major undeveloped area within the floodplain is Belleau Woods, a heavily wooded DuPage County Forest Preserve District property. Finally, there are several large lots and clusters of smaller lots that are undeveloped and are partially or completely inundated by the regulatory floodplain. Cumulatively these lots provide significant stormwater storage.


Winfield Creek is a typical Northeastern Illinois urban stream. Between the confluence with the West Branch of the DuPage River and Bloomingdale Road the open-channel (stream) system of Winfield Creek is approximately 6.7 miles long, and has an average bed slope of 0.1 percent. There are 36 hydraulic structures along Winfield Creek consisting of bridges, culverts, low flow dams, and weirs. There are several pedestrian or utility crossings at Community Park, Northside Park, Dorchester Avenue, and downstream of Summit Drive. During field reconnaissance these pedestrian crossings were assessed to by hydraulically nonobtrusive to flows. Along the main channel there are over 25 storm sewer outfalls that discharge stormwater from the tributary areas. Between the confluence and Roosevelt Road (at Shaffner Road) is the channel reach within the Village of Winfield. The properties adjacent to the floodplain are mostly residential with a few 1-story office buildings, one industrial building and also some storage and utility structures belonging to DuPage County. There are numerous undeveloped lots adjacent to the creek and in some situations, the creek bisects the lot, many of which the regulatory floodplain completely inundates. A large number of these lots appear to be impractible to develop under the DuPage County Stormwater and Floodplain Ordinance. The bridge or culvert crossings modeled in this reach are Summit Drive, Park Street, Winfield Road, Church Street, East Street (extention), Manchester Road, and Roosevelt Road (at Shaffner Road). The floodplain is generally flat and with some residential encroachment. Between Roosevelt Road (at Shaffner) and Geneva Road is the channel reach within the City of Wheaton. There are three large undeveloped areas in the floodplain in this reach: Belleau Woods (DuPage County Forest Preserve District), Lincoln Marsh (Wheaton Park District and DuPage County Forest Preserve District), and Northside Park (Wheaton Park District). There is a weir structure at Northside Park that divides two level pool areas by approximately 3.5 feet during low-flow conditions. The upstream level pool is called Upper Northside Park while the downstream level pool area is called Lower Northside Park. Lincoln Marsh and Lower Northside Park provide approximately 318 acre-feet of storage up to elevation 731.0’ and Upper Northside Park provides approximately 131 acre-feet of storage up to elevation 732.0’. These two relatively large storage areas considerably attenuate the flows entering Northside Park from Main Street and surrounding tributary areas. Belleau Woods provides approximately 87 acre-feet of storage for the August 1972 storm event between elevation 722.0’ at the downstream end (Shaffner Road) and elevation 723.7’ at the upstream property boundary.


Immediately east of Belleau Woods is St. Francis High School. Adjacent to the school are apartment buildings that have an off-line wet-bottom detention facility. Between Roosevelt Road (upstream crossing) and the Chicago and Northwestern Railroad, the floodplain area is mainly composed of residential lots of approximately ¼ to are two off-line dry-bottom floodplain storage areas with no effective outlet control between Beverly Avenue and Dorchester Lane. Just north of Childs Street is Emerson School. Upstream (north) of the Chicago and Northwestern Railroad and south of the Prairie Path, the area is part industrial, part residential, and part Lincoln Marsh. Between Lincoln Avenue and approximately 500’ west of Main Street (Wheaton) are Lincoln Marsh and Northside Park. Where Winfield Creek crosses Main Street is an area comprised mostly of commercial structures. Just east of Main Street and south of Cole Avenue is St. Mark’s Church. Between Cole Avenue and Geneva Road the creek flows through the backyards of a residential area.

1/3 acre in size. There

North of Geneva Road is Community Park which is located in the Village of Carol Stream. Similar to Northside Park, Community Park consists of an on-line lake with surrounding parkland and provides approximately 154 acre-feet of storage up to elevation 746.0. This storage results in considerable attenuation of the upstream tributary flows, including the flow from an open-channel tributary that crosses the Great Western Railroad embankment and St. Charles Road, both crossings west of Bloomingdale Road. The Upper Winfield Creek Basin is defined to be the headwaters of Winfield Creek near the intersection of North Avenue and Bloomingdale Road downstream to the intersection of St. Charles Road and Bloomingdale Road. The upper basin, which once was a series of wetlands and natural drainage channels, has been converted by development into a series of storage basins and storm sewer systems with overflow paths. The only “natural” wetland left in this part of the watershed is the Olive Court wetland at the northwest corner of North Avenue and Bloomingdale Road in Bloomingdale Township. This wetland has been degraded by development, sedimentation and filling. It serves as detention storage and flood control for two older subdivisions that were built before the days of stormwater detention requirements: Glen Hill in the Village of Glendale Heights and Glen Ellyn Countryside in unincorporated DuPage County. The total tributary area to the wetland is 209.5 acres. The flow then crosses under the intersection of Bloomingdale Road and North Avenue into a large detention facility for the commercial development at that corner. From this facility there is a storm sewer and overland route through an apartment complex into its detention system. The flow leaves via a storm sewer and overland route. The surface flow


crosses the Prairie Path and through a residential area before joining the Winfield Creek mainstem downstream of St. Charles Road. A detailed description of the hydraulic structures and associated drainage features of the stream can be found under the “Drainage Network” subsection. 3.7.17.2 Hydrologic Analysis Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Winfield Creek. Discharges for the 10-year, 50-year, and 100-year floods for Winfield Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. The USGS stream gages used for the hydrologic analyses Winfield Creek studied in detail are presented in Table WBWF.1 below: Table WBWF.1: USGS Stream Gages Used for Hydrologic Analysis of Winfield Creek

USGS Stream Gages

Flooding Source USGS Drainage Area Record and Location Gage # (sq. miles) (years) Winfield Creek at Winfield 05540020 6.95 15 Frequency-discharge data for Winfield Creek were developed through the use of the Chicago Metropolitan Study, DuPage River Basin (USACE, 1973) performed by the USACE’s Hydrologic Engineering Center. In the Chicago Metro Study, the DuPage River basin above Shorewood, Illinois, was divided into 29 subareas and a generalized HEC-1 rainfall-runoff computer model was calibrated for the basin (USACE, 1973). One-hour increments of a 24-hour storm rainfall, obtained from the U.S. Weather Bureau Technical Paper No. 40 (U.S. Department of Commerce, 1961), were entered into the HEC-1 model of the basin to obtain the 10-, 50-, and 100-year flood peak discharges. Point rainfall-frequency curves derived from Technical Paper No. 40 were extrapolated to obtain a 500-year rainfall distribution, from which the 500-year flood peak discharges were computed. Since the discharges computed by this method applied to the total subarea tributary to the West Branch DuPage River in which each


stream was located, the corresponding subarea discharges were reduced by the square root of the drainage area ratio for each stream. Discharges for Winfield Creek below Main Street, computed by the above methods, were decreased following a reservoir routing analysis for the area between Chicago and North Western railroad bridges and Main Street. (A reservoir routing analysis was used because of the large ponding area that is very flat.) A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBWF.2. Table WBWF.2: Winfield Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Winfield Creek

- at Roosevelt and Schaffner Road 6.95 430 585 665 935

- at Beverly Avenue 6.35 340 450 510 710 - at Chicago and North- Western Railroad 5.60 225 290 320 425 - at low flow dam at mile 4.60 4.30 320 430 490 695 - at Main Street 3.69 370 510 590 855 - at d/s corporate limits for Village of Carol Stream 2.92 330 455 530 760 3.7.17.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Channel cross-section data were obtained from field surveys. All bridges and culverts were surveyed to obtain elevation data and structural geometry Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map.

Water-surface profiles for Winfield Creek were computed through use of the USACE HEC-2 step-backwater computer program (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973).


Profiles were determined for the 10-, 50-, 100-, and 500-year floods (Exhibit 1). For Winfield Creek between the Chicago and North Western Railroad and Main Street, two sets of profiles were computed using different sets of assumptions: (1) maximum inflow at Main Street and corresponding starting water-surface elevations at the railroad, and (2) maximum “pond” elevations behind the railroad bridge and corresponding discharges through the reach. The profiles for the second case were used since they were higher for the entire reach. Starting water-surface elevations for Winfield Creek were calculated using the slope/area method. Roughness coefficients (Manning’s “n”) for Winfield Creek were estimated by field inspection. Roughness coefficients (Manning’s “n”) for the hydraulic computations were assigned on the basis of field inspection, analyses of field photographs (USACE, 1973-1979) and sound engineering judgment. Refer to Table WBWF.3 for further information regarding roughness coefficients. Table WBWF.3: Winfield Creek Manning’s “n” Values



- Winfield Creek 0.015 - 0.055 0.045 - 0.100 3.7.17.4 Flood Boundaries To reference the flood boundaries for Winfield Creek, see Map Panels: 0207, 0208, 0403, 0406, 0501, 0502, 0504 and 0505. 3.7.17.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Winfield Creek (WBWF)WBWF0001 116 273 816 0.9 712.4 712.4 712.5 0.11 2

WBWF0002 533 189 480 1.6 712.4 712.4 712.5 0.11 2

WBWF0003 925 221 507 1.5 712.4 712.4 712.5 0.11 2

WBWF0004 1,600 279 493 1.5 713.6 713.6 713.7 0.11

WBWF0005 1,684 306 761 1.0 713.8 713.8 713.9 0.11

WBWF0006 2,006 307 754 1.0 715.4 715.4 715.5 0.11

WBWF0007 2,210 288 723 1.0 715.5 715.5 715.6 0.11

WBWF0008 2,441 263 675 1.1 717.2 717.2 717.3 0.11

WBWF0009 2,900 265 1,216 0.6 717.3 717.3 717.4 0.11

WBWF0010 3,748 512 2,473 0.3 717.3 717.3 717.4 0.11

WBWF0011 4,530 607 2,619 0.3 717.3 717.3 717.4 0.11

WBWF0012 5,400 183 599 1.3 717.4 717.4 717.5 0.11

WBWF0013 6,362 363 876 0.8 717.9 717.9 718.0 0.11

WBWF0014 7,230 700 1,958 0.4 718.1 718.1 718.2 0.11

WBWF0015 7,603 174 384 1.8 718.3 718.3 718.4 0.11

WBWF0016 8,131 257 623 1.1 719.5 719.5 719.6 0.11

WBWF0017 8,730 275 489 1.4 720.3 720.3 720.4 0.11

WBWF0018 9,000 685 1,932 0.3 722.2 722.2 722.3 0.11


AND INCORPORATED AREAS WINFIELD CREEK (WBWF)

In feet above West Branch DuPage River2 Elevations include backwater effects from the West Branch DuPage River

1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Winfield Creek (WBWF)WBWF0019 11,119 401 1,017 0.7 723.5 723.5 723.6 0.11

WBWF0020 12,500 147 584 1.1 724.4 724.4 724.5 0.11

WBWF0021 13,440 103 187 3.6 724.6 724.6 724.7 0.11

WBWF0022 14,487 31 140 3.6 726.5 726.5 726.5 0.01

WBWF0023 15,622 173 497 1.0 727.5 727.5 727.6 0.11

WBWF0024 16,890 100 365 0.9 728.1 728.1 728.2 0.11

WBWF0025 17,296 34 182 1.8 728.4 728.4 728.4 0.01

WBWF0026 17,732 280 628 0.5 728.5 728.5 728.5 0.01

WBWF0027 18,930 126 234 1.4 728.9 728.9 728.9 0.01

WBWF0028 19,805 40 196 1.6 731.0 731.0 731.1 0.11

WBWF0029 20,100 43 229 1.4 731.1 731.1 731.2 0.11

WBWF0030 20,810 120 417 0.8 731.4 731.4 731.5 0.11

WBWF0031 21,650 1,710 74 4.3 732.2 732.2 732.3 0.11

WBWF0032 24,102 571 3,325 0.1 732.2 732.2 732.3 0.11

WBWF0033 24,389 494 2,365 0.1 732.2 732.2 732.3 0.11

WBWF0034 24,975 669 2,590 0.2 732.2 732.2 732.3 0.11

WBWF0035 25,783 655 2,248 0.2 732.2 732.2 732.3 0.11

WBWF0036 27,115 320 420 1.2 732.5 732.5 732.6 0.11




1

TAB

LE 5

FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Winfield Creek (WBWF)WBWF0037 27,493 33 114 5.2 732.6 732.6 732.7 0.11

WBWF0038 28,105 112 256 2.1 733.9 733.9 734.0 0.11

WBWF0039 28,749 77 306 1.7 738.7 738.7 738.8 0.11

WBWF0040 30,133 57 151 3.5 744.1 744.1 744.1 0.01

WBWF0041 30,793 113 326 1.6 744.7 744.7 744.7 0.01

WBWF0042 30,989 455 1,029 0.5 747.0 747.0 747.0 0.01

WBWF0043 32,646 175 557 1.0 747.1 747.1 747.1 0.11

WBWF0044 33,272 330 2,249 0.3 747.1 747.1 747.1 0.01

WBWF0045 33,655 60 367 1.4 747.1 747.1 747.1 0.01

WBWF0046 35,451 38 73 3.6 748.0 748.0 748.0 0.01




1

TAB

LE 5

690

695

700 700

705 705

710 710

715 715

720 720

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

212P

WBW

F000

1

WBW

F000

2

WBW

F000

3

WBW

F000

4W

BWF0

005

WBW

F000

6

WBW

F000

7

WBW

F000

8

WBW

F000

9

WBW

F001

0

WBW

F001

1

WBW

F001

2

WBW

F001

3

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

FARM

BRI

DGE

SUM

MIT

DRI

VE

PARK

STR

EET

WIN

FIEL

D RO

AD

CHUR

CH S

TREE

T

PRIV

ATE

DRIV

E

MAN

CHES

TER

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED



700

705

710 710

715 715

720 720

725 725

730 730

6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

213P

WBW

F001

4

WBW

F001

5

WBW

F001

6

WBW

F001

7

WBW

F001

8

WBW

F001

9

WBW

F002

0

ROOS

EVEL

T RO

AD

SCHA

FFNE

R RO

AD

HIGH

SCH

OOL

ROAD

ROAD

TO

APAR

TMEN

TS


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


705

710

715 715

720 720

725 725

730 730

13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

214P

WBW

F002

1

WBW

F002

2

WBW

F002

3

WBW

F002

4

WBW

F002

5

WBW

F002

6

WBW

F002

7

W. R

OOSE

VELT

ROA

D

S. B

EVER

LY S

TREE

T

FOOT

BRID

GEDO

RCHE

STER

AVE

NUE

FOOT

BRID

GE

WOO

DLAW

N ST

REET

W. C

HILD

S ST

REET

PRIV

ATE

ROAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


710

715

720 720

725 725

730 730

735 735

740 740

19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

215P

WBW

F002

8

WBW

F002

9

WBW

F003

0

WBW

F003

1

WBW

F003

2

WBW

F003

3

WBW

F003

4

WBW

F003

5

W. M

ANCH

ESTE

R RO

AD

RAIL

ROAD

W. U

NION

AVE

NUE

W. L

INCO

LN A

VENU

E

ILLI

NOIS

PRA

IRIE

PAT

H

GARY

AVE

NUE

ELLI

S AV

ENUE

EXT

ENDE

D

LOW

FLO

W D

AM

LOW

FLO

W D

AM

FOOT

BRID

GE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERT

710

715

720 720

725 725

730 730

735 735

740 740

745 745

750 750

26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

216P

WBW

F003

6

WBW

F003

7

WBW

F003

8

WBW

F003

9

WBW

F004

0

WBW

F004

1

WBW

F004

2

WHE

ATON

COU

RT

MAI

N ST

REET

CONF

LUEN

CE O

F W

INFI

ELD

CREE

K TR

IBUT

ARY

DRIV

E TO

ST.

MAR

KS S

CHOO

L

E. C

OLE

AVEN

UE

PADD

OCK

COUR

T

GENE

VA R

OAD


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


725

730

735 735

740 740

745 745

750 750

32500 33000 33500 34000 34500 35000 35500

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

FIEL

D CR

EEK

(WBW

F)

217P

WBW

F004

3

WBW

F004

4

WBW

F004

5

WBW

F004

6FA

RM R

OAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


3.7.18 Winding Creek (WBWG)

3.7.18.1 Tributary Description Winding Creek is a 732-acre watershed that is tributary to the West Branch DuPage River. Communities that contribute watershed area to Winding Creek are Naperville and Unincorporated DuPage County. The overall land use for the watershed is single-family residential.

Winding Creek begins on the south side of 75th Street in the City of Naperville, just east of Shepherd Drive. Flow proceeds to the southeast passing between subdivision streets until crossing under Modaff Road and 79th Street. The Creek enters a conduit that runs under 79th Street all the way to the confluence with the West Branch DuPage River. 3.7.18.2 Hydrologic Analysis

Hydrologic analyses were carried out to establish the peak discharge-frequency relationship for Winding Creek. Discharges for the 10-year, 50-year, and 100-year floods for Winding Creek were computed using the log-Pearson Type III method (U.S. Department of Commerce, 1976) for gaged streams and regional equations for ungaged streams (U.S. Department of the Interior, 1973; State of Illinois, 1973). The 500-year flood discharges for streams studied in detail were estimated by straight-line extrapolation. For Winding Creek, synthetic frequency-discharge curves were derived using regional statistics developed in the Chicago study. These discharges assume zero skew. Discharges for the 500-year floods of all streams were determined by linear extrapolation of a log probability curve of flood discharges computed for frequencies of up to 100 years.

A summary of the drainage area-peak discharge relationships for the portions of the streams studied by detailed methods is shown in Table WBWG.1. Table WBWG.1: Winding Creek Summary of Discharges

Summary of Discharges Flooding Source Drainage Peak Discharges (cfs) And Location Area (mi2) 10-yr 50-yr 100-yr 500-yr Winding Creek

- at mouth 1.50 195 340 420 630


3.7.18.3 Hydraulic Analysis Analysis of the hydraulic characteristics of flooding from the sources studied was carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Locations of selected cross-sections used in the hydraulic analysis are shown on the Flood Profiles and on the Flood Insurance Rate Map. Both overbank and channel cross sections for Winding Creek were field surveyed. Water-surface elevations for Winding Creek were computed for the 10-, 50-, 100-, and 500-year floods using a HEC-2 computer step-backwater model (USACE, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, 1973). The depth of shallow flooding along Bailey Road from Winding Creek in the City of Naperville was also computed using a HEC-2 model. The excess 100-year discharge which the underground storm sewer was incapable of handling was routed across surveyed ground-surface cross sections.

Starting water-surface elevations for Winding Creek were calculated using the slope/area method. 3.7.18.4 Flood Boundaries To reference the flood boundaries for Winding Creek, see Map Panels: 0709 and 0807. 3.7.18.5 Floodways




FLOODING SOURCE


FLOODWAY

WIDTH(FEET)

SECTIONAREA

(SQUAREFEET)



WITHOUTFLOODWAY


Winding Creek (WBWG)WBWG0001 3,554 425 2,831 0.1 678.0 678.0 678.0 0.01

WBWG0002 4,452 106 204 0.6 681.3 681.3 681.3 0.01

WBWG0003 5,525 221 437 0.3 681.3 681.3 681.3 0.01

WBWG0004 5,935 44 118 1.0 681.4 681.4 681.4 0.01


AND INCORPORATED AREAS WINDING CREEK (WBWG)


TAB

LE 5

640

645

650 650

655 655

660 660

665 665

670 670

675 675

680 680

685 685

0 400 800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

DING

CRE

EK (W

BWG)

218PW

BWG0

001

WBW

G000

2

CONF

LUEN

CE W

ITH

WES

T BR

ANCH

DUP

AGE

RIVE

R

SWAL

LOW

ROA

D

CHAT

COU

RT

VERD

IN L

ANE

TERR

ANCE

DRI

VE


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERTS

CULVERTS

660

665

670 670

675 675

680 680

685 685

690 690

5200 5600 6000 6400 6800

ELEV

ATIO

N IN

FEE

T (N

GVD

29)


FEDE

RAL

EMER

GENC

Y M

ANAG

EMEN

T AG

ENCY

DUPA

GE C

OUNT

Y, IL

AND

INCO

RPOR

ATED

ARE

AS

FLOO

D PR

OFIL

ES

WIN

DING

CRE

EK (W

BWG)

219P

WBW

G000

3

WBW

G000

4

MOD

AFF

ROAD

LIM

IT O

F DE

TAIL

ED S

TUDY


100-YEAR FLOOD

50-YEAR FLOOD

10-YEAR FLOOD

STREAM BED


CULVERTS

4.0 INSURANCE APPLICATION

4.1 Reach Determinations Reaches are defines as lengths of watercourses having relatively the same flood hazard, based on the average weighted difference in water-surface elevation between the 10- and 100-year floods. This difference does not have a variation greater than that indicated in the following table for more than 20 percent of the reach. Average Difference Between 10- and 100-year Floods Variation Less than 2 feet 0.5 foot 2 to 7 feet 1.0 foot 4.2 Flood Hazard Factors The FHF is the FIA device used to correlate flood information with the insurance rate tables. Correlations between property damage from floods and their FHF’s are used to set actuarial insurance premium rate tables based on FHFs from 005 to 200.

The FHF for a reach is the average weighted difference between the 10- and 100-year flood water-surface elevations expressed to the nearest 0.5 foot, and shown as a three-digit code. For example, if the difference between water-surface elevations of the 10- and 100-year floods is 0.7 foot, the FHF is 005, if the difference is 1.4 feet, the FHF is 015; if the difference is 5.0 feet, the FHF is 050. When the difference between to 10- and 100-year water-surface elevation is greater than 10.0 feet, accuracy for the FHF is to the nearest foot.

4.3 Flood Insurance Zones

For flood insurance rating purposes, flood insurance zone designations are assigned to a community based on the results of the engineering analyses. The zones are as follows:

Zone A Zone A is the flood insurance rate zone that corresponds to the 100-year

floodplains that are determined in the FIS by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no base flood elevations or depths are shown within this zone.

Zone AE

Zone AE is the flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the FIS by detailed methods. In most instances,

41

whole-foot base flood elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone.

Zone AH

Zone AO

Zone AH is the flood insurance rate zone that corresponds to the areas of 100-year shallow flooding (usually areas of ponding) where average depths are between 1 and 3 feet. Whole-foot base flood elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone.

Zone AO is the flood insurance rate zone that corresponds to the areas of 100-year shallow flooding (usually sheet flow on sloping terrain) where average depths are between 1 and 3 feet. Average whole-depths derived from the detailed hydraulic analyses are shown within this zone.

Zone AR

Area of special flood hazard formerly protected from the 1% annual chance flood event by a flood control system that was subsequently decertified. Zone AR indicates that the former flood control system is being restored to provide protection from the 1% annual chance or greater flood event.

Zone A99

Zone V

Zone V is the flood insurance rate zone that corresponds to the 100-year coastal floodplains that have additional hazards associated with storm waves. Because approximate hydraulic analyses are performed for such areas, no base flood elevations are shown within this zone.

Zone VE

Zone VE is the flood insurance rate zone that corresponds to the 100-year coastal floodplains that have additional hazards associated with storm waves. Whole-foot base flood elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone.

Zone X

Zone A99 is the flood insurance rate zone that corresponds to areas of the 100-year floodplain that will be protected by a Federal flood protection system where construction has reached specified statutory milestones. No base flood elevations or depths are shown within this zone.

42

Zone X is the flood insurance rate zone that corresponds to areas outside the 500-year floodplain, areas within the 500-year floodplain, and to areas of 100-year flooding where average depths are less than 1 foot, areas of 100-year flooding where the contributing drainage area is less than 1 square mile, and areas protected from the 100-year flood by levees. No base flood elevations or depths are shown within this zone.

Zone D

Zone D is the flood insurance rate zone that corresponds to unstudied areas where flood hazards are undetermined, but possible.

4.4 Flood Insurance Rate Map Description

The FIRM is designed for flood insurance and floodplain management applications.

For flood insurance applications, the map designates flood insurance rate zones as described in Section 5.0 and, in the 100-year floodplains that were studied by detailed methods, shows selected whole-foot base flood elevations or average depths. Insurance agents use the zones and base flood elevations in conjunction with information on structures and their contents to assign premium rates for flood insurance policies.

For floodplain management applications, the map shows by tints, screens, and symbols, the

100- and 500-year floodplains. Floodways and the locations of selected cross sections used in the hydraulic analyses and floodway computations are shown where applicable.

The current FIRM presents flooding information for the entire geographic area of DuPage

County. Previously, separate Flood Hazard Boundary Maps and/or FIRMs were prepared for each identified flood-prone incorporated community and the unincorporated areas of the county. This countywide FIRM also includes flood hazard information that was presented separately on Flood Boundary and Floodway Maps (FBFMs), where applicable.

43

5.0 OTHER STUDIES FISs have been prepared for Kane County and incorporated areas (♦), Will County and

incorporated areas (♦), and Cook County and incorporated areas (♦). Information pertaining to revised and unrevised flood hazards for each jurisdiction within

DuPage County has been compiled into this FIS. Therefore, this FIS supersedes all previously printed FIS Reports, FHBMs, FBFMs, and FIRMs for all of the incorporated and unincorporated jurisdictions within DuPage County.

Following is a list of reports and studies pertaining to the flood hazards within DuPage County: Flood Water Management Plan of the Des Plaines River Floodplain Maps and Flood Profiles for Salt Creek and Westwood Creek A Flooding and Storm Sewer Report

USGS Publication “Water Resources Data for Illinois, Part 1, Surface Water Records”

Floodplain Information Report, West Branch DuPage River, Kress Creek and Klein Creek, Cook County, Illinois

An SCS Study for the Des Plaines River Basin Illinois Department of Transportation, Division of Water Resources report,

Strategic Planning Study for Flood Control – Bensenville Ditch, Bensenville, Illinois, DuPage County

Donohue & Associates, Inc., study for Addison Creek Stormwater Management System Evaluation, DuPage and Cook Counties, Illinois

Survey Report for Improvement for Spring Brook Creek Spring Brook Drainage Study West Branch Tributary to Spring Brook Creek Drainage Basin Study Engineer’s Report, Stormwater Management Plan for the Klein Creek Basin

Segment of the Bloomingdale West Project Storm Water Management Plan, a part of the Klein Creek segment of the

Bloomingdale West Project Surface Water Drainage Study of the Indian Lakes Subdivision and Environs Flood Plain Information Study on the Des Plaines River and its tributaries Lindley and Sons, Inc., Drainage Study on a tributary to the 63rd Street Ditch and

on 79th Street Ditch for the Village of Burr Ridge Baranecki, Vigilio, and Associates, Improvement Plan for Burr Ridge Illinois Division of Water Resources, Strategic Planning Study of the Winfield

Creek Basin Floodplain maps and flood profiles for Sawmill Creek and East Branch Sawmill

Creek Special Flood Hazard Information Study for the East Branch DuPage River,

Prentiss Creek, St. Joseph Creek, and Lacey Creek USGS Hydrologic Investigations Atlases USGS Flood-Prone Area Maps

44

Special Flood Hazard Information Study of the East Branch DuPage River A report by Harza Engineering, Village of Hanover Park, Illinois, West Branch

DuPage River Flood Control Plan Floodwater Management Plan for the Des Plaines River Watershed Upper Salt Creek Watershed Work Plan Des Plaines River Watershed Floodwater Management Plan and Flood Plain

Information, Maps and Profiles USACE, Chicago District, East Branch DuPage River Special Flood Hazard

Information Report A report by the State of Illinois Department of Public Works and Buildings,

Division of Waterways West Branch DuPage River Flood Plain Information Report A report analyzing flooding along Salt Creek, updated by the IDOT A Flood Hazard Information Report by Carl C. Crane, Inc., for the Chicago

District USACE A Plan of Study report on the Fox River and its tributaries Southeastern Wisconsin Regional Planning Commission Report Work Plan for Watershed Protection and Flood Prevention, Upper Salt Creek

Watershed Report on the Regulation of Construction Within the Flood Plain of Upper Salt

Creek and Tributaries, Palatine, Schaumburg, Elk Grove Township, Cook County, Illinois

Des Plaines River Flood Plain Information Maps and Profiles Regulation of Construction Within the Flood Plain of the Lower Salt Creek and

Tributaries of Cook and DuPage Counties A Comprehensive Plan for the Fox River Surface Water Drainage Control Study for the Village of Westmont Des Plaines River Flood Plain Information Maps and Profiles, Cook and DuPage

Counties, Illinois Stormwater Management Study, Village of Willowbrook Lindley and Sons, Inc., Several Letter Reports to the City of Darien, Illinois, on

Lake Hinsdale and Sawmill Creek SCS publication, Upper Salt Creek Watershed Work Plan of the Busse Woods

Reservoir City of Wood Dale Comprehensive Storm Drainage Report

45

6.0 LOCATION OF DATA Information concerning the pertinent data used in the preparation of this FIS can be

obtained by contacting FEMA, Federal Insurance and Mitigation Division, 536 South Clark Street, Sixth Floor, Chicago, Illinois 60605.

46

7.0 REFERENCES AND BIBLIOGRAPHY

American Guide Series. (1941). DuPage County: A Descriptive and Historical Guide, 1831-1939. Baranecki, Vigilio, and Associates. (December 1977). Improvement Plans for Burr Ridge Meadows, Phase I. Burr Ridge, Illinois. Barton-Aschman Associates, Inc. (August 1976). First Year Planning Program, Reconnaissance Study. Baxter and Woodman, Inc. (January 1976). Winfield Creek Drainage Investigation: Engineer’s Report. Crystal Lake, Illinois. Baxter and Woodman, Inc. (October 1975). Winfield Creek Retention Study. Crystal Lake, Illinois. Chow, V. T. (1964). Handbook of Applied Hydrology. McGraw Hill Book Company, Inc. Chow, V. T. (1959). Open Channel Hydraulics. McGraw Hill Book Company, Inc. “Damage Estimate Set.” (August 29, 1972). The Daily Journal, Volume 40, No. 226, Page 1.

Des Plaines River Watershed Steering Committee, and U.S. Department of Agriculture, Soil Conservation Service. (1976). Des Plaines River Floodwater Management Plan and Environmental Assessment. Des Plaines River Watershed Steering Committee. (December 1975). Des Plaines River Flood Plain Information Maps and Profiles, Cook and DuPage Counties, Illinois. Dougherty, R. L., and J. B. Fanzini. (1977). Fluid Mechanics with Engineering Applications. McGraw-Hill Book Company, Inc. Downers Grove Reporter. (October 14, 1954; July 18, 1957; and August 31, 1972). Downers Grove, Illinois. DuPage County Zoning Ordinance. (December 10, 1935, as amended). DuPage County Board of Supervisors. Federal Emergency Management Agency. (April 1982). Flood Insurance Study, DuPage County, Illinois (Unincorporated Areas).

47

Federal Emergency Management Agency, Federal Insurance Administration. (February 18, 1981). Flood Insurance Study, City of Oak Brook Terrace, DuPage County, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (February 1981). Flood Insurance Study, Village of Villa Park, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (April 1981). Flood Insurance Study, Village of Downers Grove, Illinois. Federal Emergency Management Agency, Federal Insurance Administration. (May 1981). Flood Insurance Study, Village of Roselle, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (October 1981). Flood Insurance Study, Village of Burr Ridge, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (January 1980). Flood Insurance Study, Village of Willowbrook, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (September 1980). Flood Insurance Study, Village of Lisle, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (June 1979). Flood Insurance Study, City of Wheaton, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (October 1978). Flood Insurance Study, Village of Lombard, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (October 1977). Flood Insurance Study, Village of Itasca, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (In progress). Flood Insurance Study, Village of Downers Grove, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (In progress). Flood Insurance Study, City of Elmhurst, Illinois. Washington, D.C. Federal Emergency Management Agency, Federal Insurance Administration. (November 6, 2000). Flood Insurance Study, Cook County, Illinois (Unincorporated Areas). Washington, D.C. Floodplain Topographic Maps. (Champaign, Illinois, 1973). Salt Creek Watershed, Scale 1:4,800, Contour Interval 2 feet. Soil Conservation Service. Glen Ellyn News. (August 30, 1972).

48

Hansen, Harry (editor). (1974). Illinois, A Descriptive and Historical Guide. New York, Hastings House. Harza Engineering Company. (1971). West Branch DuPage River Flood Control Plan. Chicago, Illinois. Illinois Department of Public Works and Buildings, Division of Waterways. (1962). Survey Report for Flood Control, DuPage River, DuPage and Will Counties. Illinois Department of Transportation, Division of Water Resources. (January 1980). Regulation of Construction Within the Floodplain of Lower Salt Creek and Tributaries. Springfield, Illinois. Illinois Department of Transportation, Division of Water Resources. (Cook, DuPage, and Lake Counties, Illinois, July 1979). Regulatory Floodplain, Lower Salt Creek, Scale 1:400, Contour Interval 4 feet. Illinois Department of Transportation, Division of Water Resources. (1975). Strategic Planning Study of Waubansee Creek from Montgomery to Oswego, Kane and Kendall Counties, Illinois. Illinois Department of Transportation, Division of Water Resources. (Springfield, Illinois, 1973, and revised statutes, Chapter 19, 52 et seq., 1975). Rules and Regulations, Regulations of Construction Within Floodplains Established Pursuant to Section 654, Chapter 19, Illinois Revised Statutes. Illinois Department of Transportation, Division of Water Resources. (1973). Magnitude and Frequency of Floods in Illinois. J. M. Carns (author). Springfield, Illinois. Illinois Department of Transportation, Division of Water Resources. (1973). Rules and Regulations, Regulation of Construction Within Flood Plains Established Pursuant to Section 65F, Chapter 19, Illinois Revised Statutes. Springfield, Illinois. Illinois Division of Water Resources. (1977). Guidelines for Operational Procedures at McHenry Dam. Lardner, J. P. and M. L. Terstriep. (November 1975). Illinois State Water Survey, Waubansee Creek Floodplain Analysis. Lindley and Sons, Inc. (February 1974). Northcentral Storm Drainage Report. Naperville, Illinois. Mackie Consultants, Inc. (1977). Engineers Report, Stormwater Management Plan for the Klein Creek Basin Segment of the Bloomingdale West Project.

49

North Central Chicago Engineering Division-Hydraulics. (1978). Memorandum for File, Fox River, Special Flood Hazard Study Chain of Lakes, McHenry and Lake Counties, Illinois. Northeastern Illinois Planning Commission. (Village of Downers Grove, Illinois, flown in March-April 1975). Topographic Maps compiled from air photos, Scale 1:1,200, Contour Interval 1 Foot. Northeastern Illinois Planning Commission, in cooperation with the Chicago District, U.S. Army Corps of Engineers. (West Branch DuPage River, Cook and Will Counties, Illinois; Madison, Wisconsin, Alster and Associates, Inc., Photographed April 16, 1974). Flood Plain Topographic Maps, Scale 1:4,800. Northeastern Illinois Planning Commission. (April 1973). Suburban Factbook. Southeastern Wisconsin Regional Planning Commission. (April 1969). Planning Report No. 12, Volumes One and Two. A Comprehensive Plan for the Fox River Watershed. Waukesau, Wisconsin. State of Illinois, Office of the Secretary of State. (1976). Springfield, Illinois. State of Illinois. (July 1976). Counties and Incorporated Municipalities of Illinois. State of Illinois, Department of Transportation, Division of Water Resources. (Madison, Wisconsin, September 1976). DuPage River Flood Plain, Scale 1:4,800, Contour Interval 2 feet. Alster & Associates Engineering. State of Illinois, Department of Transportation, Division of Water Resources. (Sheboygan, Wisconsin, December 1975). Flood Plain Topographic Map for Salt Creek Watershed, Scale 1:4,800, Contour Interval 4 feet. Aero-Metric Engineering, Inc. State of Illinois, Department of Public Works and Buildings, Division of Waterways (currently Department of Transportation, Division of Water Resources). (1975). Survey Report for Development of Fox River, Ottawa to McHenry Dam, La Salle, Kane, Kendall, McHenry, and Lake Counties, Illinois. State of Illinois, Department of Transportation, Division of Water Resources. (December 1975). Preliminary Report on the Regulation of Construction with the Floodplain of Waubansee Creek and Tributary. State of Illinois, Department of Transportation, Division of Water Resources. (1973). Magnitude and Frequency of Floods in Illinois. J. M. Carns (author). Springfield, Illinois. State of Illinois, State Water Survey. (October 1975). Poplar Creek Flood Plain Report. J. M. Jess (author). Springfield, Illinois.

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State of Illinois, Department of Public Works and Buildings, Division of Waterways. (1962). Survey Report for Flood Control, DuPage River, DuPage and Will Counties, Illinois. Chicago, Illinois. State of Illinois, Department of Public Works and Buildings, Division of Waterways (currently Department of Transportation, Division of Water Resources). (1960). Survey Report for Flood Control, Indian Creek and Tributaries, Aurora and Vicinity, Kane County, Illinois. State of Illinois, Department of Public Works and Buildings, Division of Waterways (currently Department of Transportation, Division of Water Resources). (1954). Floods in Illinois, Magnitude and Frequency. W. D. Mitchell (author). University of Illinois, Department of Agronomy, Agricultural Experiment Station. (1950). AG-1443, Illinois Soil Type Descriptions. Y. L. Wascher, J. B. Fehrenbacher, R. T. Odell, and P. T. Veale (authors). U.S. Army Corps of Engineers, Hydrologic Engineering Center. (May 1991). HEC-2 Water-Surface Profiles, Generalized Computer Program. Davis, California. U.S. Army Corps of Engineers, Chicago District. (Unincorporated Areas of Kane County, Illinois, September-October 1978). , Scale 1:4,800, Contour Interval four feet.

Topographic Maps

U.S. Army Corps of Engineers, Chicago District. (October 1977).

. DuPage Basin Study Area. Preliminary

Environmental Inventory U.S. Army Corps of Engineers. (November 1976). . HEC-2 Water-Surface Profiles U.S. Army Corps of Engineers, Chicago District. (1976).

. Chicago, Illinois. A Plan of Study for the Fox

River and its Tributaries U.S. Army Corps of Engineers, Chicago District. (June 1975). Flood Plain Information, West Branch DuPage River, Kress Creek, Klein Creek, DuPage County, Illinois. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (June 1974).

.

Balanced Hydrograph Techniques for Five Selected Basins in the Chicago Metropolitan Area – Memo No. 428 U.S. Army Corps of Engineers, Hydrologic Engineering Center. (January 1973).

. Davis, California. HEC-1

Flood Hydrograph Package, Computer Program, 723-X6-L2010 U.S. Army Corps of Engineers, Hydrologic Engineering Center. (September 1973). Special Project Memo No. 412,

. Des Plaines River Basin, Duplicate Lock Hydrology

Study

51

U.S. Army Corps of Engineers, Hydrologic Engineering Center. (October 1973). HEC Special Project Memo No. 415, Chicago Metropolitan Area Study, DuPage River Basin. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (October 1973). HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A. Davis, California. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (February 1972). HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A. Davis, California. U.S. Department of Agriculture, Soil Conservation Service. (April 1979). Soil Survey of Kane County, Illinois. U.S. Department of Agriculture, Soil Conservation Service. (June 1978). Floodway Determination Computer Program, Technical Release 64. U.S. Department of Agriculture, Soil Conservation Service, Central Technical Unit. (1977). HUD-15 Computer Program. Hyattsville, Maryland. U.S. Department of Agriculture, Soil Conservation Service. (May 1976). Technical Release No. 61, WSP-2 Computer Program. Washington, D.C. U.S. Department of Agriculture, Soil Conservation Service. (January 1975). Technical Release No. 55, Urban Hydrology for Small Watersheds. U.S. Department of Agriculture, Soil Conservation Service. (June 1974). WSP-2 Water-Surface Profiles Users Manual. R. Pasley and O. Lee (authors). U.S. Department of Agriculture, Soil Conservation Service. (February 1974). SCS TR-20 Project Formulation Computer Program. Champaign, Illinois. U.S. Department of Agriculture, Soil Conservation Service. (March 1974). WSP-2 Water-Surface Profile Computer Program. Champaign, Illinois. U.S. Department of Agriculture, Soil Conservation Service. (1973). Work Plan for Watershed Protection and Flood Prevention, Upper Salt Creek Watershed. Lincoln, Nebraska. U.S. Department of Agriculture, Soil Conservation Service. (1965). Technical Release No. 20, Computer Program, Project Formulation, Hydrology. Washington, D.C. U.S. Department of Agriculture, Soil Conservation Service. (December 1963). Guide for Selecting Roughness Coefficients. Champaign, Illinois. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Data Service. (1977). Climatological Data, Illinois. Asheville, North Carolina.

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U.S. Department of Commerce, National Oceanic and Atmospheric Administration. (1976). “Local Climatological Data for Chicago, Illinois.” U.S. Department of Commerce. (March 1976). Bulletin No. 17, Guidelines for Determining Flood Flow Frequency. Washington, D.C. U.S. Department of Commerce, National Oceanic and Atmospheric Administration. (1975). Climatological Data, Illinois, Annual Summary, 1974, Volume 79, Number 13. U.S. Department of Commerce, Bureau of the Census. (1971). Census of Population, Number of Inhabitants, Illinois. Washington, D.C. U.S. Department of Commerce, Bureau of the Census. (June 1970). Current Population Report, Series P-28, No. 1552. U.S. Government Printing Office. Washington, D.C. U.S. Department of Commerce, Weather Bureau. (1963). Technical Paper No. 40, Rainfall Frequency Atlas of the United States (for Durations from 30 minutes to 24 hours and return periods from 7 to 100 years). Washington, D.C. U.S. Department of Commerce, Weather Bureau. (June 1962). Climatic Guide for Chicago, Illinois, Area. U.S. Department of Commerce, National Weather Service. (May 1961). Rainfall Frequency Atlas of the United States, Technical Paper No. 40. U.S. Government Printing Office. Washington, D.C. U.S. Department of Commerce, Bureau of Public Roads. (September 1961). Hydraulic Charts for the Selection of Highway Culverts, Hydraulic Engineering Circular No. 5. U.S. Government Printing Office. Washington, D.C. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (November 6, 2000). Flood Insurance Study, Indian Head Park, Illinois. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (January 1979). Flood Insurance Study, Village of Glen Ellyn, Illinois. Washington, D.C. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (November 1979). Flood Insurance Study, City of West Chicago, Illinois. Washington, D.C. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (March 1979). Flood Insurance Study, Village of Addison, Illinois. Washington, D.C.

53

U.S. Department of Housing and Urban Development, Federal Insurance Administration. (June 1979). Flood Insurance Study, Village of Woodbridge, Illinois. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (June 1979). Flood Insurance Study, City of Aurora, Illinois. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (March 1979). Flood Insurance Study, City of Naperville, Illinois. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (May 1978). Flood Insurance Study, Village of Hanover Park, Cook and DuPage Counties, Illinois. Washington, D.C. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (August 1978). Flood Insurance Study, Village of Glendale Heights, Illinois. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (May 1977). Flood Hazard Boundary Map, DuPage County, Illinois (Unincorporated Areas). Washington, D.C. U.S. Department of Housing and Urban Development, Federal Insurance Administration. (October 24, 1975). Flood Hazard Boundary Map, Village of Schaumburg, Cook County, Illinois. U.S. Department of the Interior, Geological Survey. (1979). Effects of Urbanization on the Magnitude and Frequency of Floods in Northeastern Illinois, 79-36. U.S. Department of the Interior, Geological Survey. (1978). Water Resources Data for Illinois, Water Year 1977. U.S. Department of the Interior, Geological Survey. (1977). Water Resources Investigations 77-117, Technique for Estimating Magnitude and Frequency of Floods in Illinois. U.S. Department of the Interior, Geological Survey. (Hinsdale Quadrangle, 1976). Hydrologic Atlas 86, Flood Plain Map, Scale 1:2,400, Contour Interval 5 Feet. U.S. Department of the Interior, Geological Survey. (1975). Water Resources Data for Illinois, Part 1, Surface Water Records. Champaign, Illinois. U.S. Department of the Interior, Geological Survey. (1974). Determination of 100-year Flood Flows in Urbanizing Regions of Northeastern Illinois. Champaign, Illinois. U.S. Department of the Interior, Geological Survey. (1973). 1972 Water Resources Data for Illinois.

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U.S. Department of the Interior, Geological Survey, in cooperation with the State of Illinois Department of Transportation, Division of Water Resources. (1973). Magnitude and Frequency of Floods in Illinois. Jack M. Carns (author). Springfield, Illinois. U.S. Department of the Interior, Geological Survey. (1973). Water Resources Data for Illinois: 1972. Champaign, Illinois. U.S. Department of the Interior, Geological Survey. (Naperville, 1972; West Chicago, 1972; Normantown, 1973; Romeville, 1973; Wheaton, 1972; Lombard, 1972; Elmhurst, 1972; Hinsdale, 1972; Sag Bridge, 1973, Illinois). 7.5-Minute Series Topographic Maps, Scale 1:24,000, Contour Interval 10 feet. U.S. Department of the Interior, Geological Survey. (Hinsdale and Sag Bridge, Illinois, photorevised 1972). 7.5-Minute Series Quadrangle Map, Scale 1:24,000, Contour Interval five feet. U.S. Department of the Interior, Geological Survey. (1967). Water Supply Paper 1849, Roughness Characteristics of Natural Channels. U.S. Government Printing Office. Washington, D.C. U.S. Department of the Interior, Geological Survey. (1965). Hydrologic Investigations Atlases for West Chicago, HA202 and Naperville, HA154. U.S. Department of the Interior, Geological Survey. (1965). Floods in Wheaton Quadrangle, Northeastern Illinois, Hydrologic Investigations Atlas HA-148. U.S. Department of the Interior, Geological Survey. (1965). Floods in Romeoville Quadrangle, Northeastern Illinois, Hydrologic Investigations Atlas HA-146. U.S. Department of the Interior, Geological Survey. (Naperville, Illinois HA-154, 1965; HA-210, 1966; HA-148, 1965, HA-146, 1965). Hydrologic Investigations Atlases. H. E. Allen and V. Jeff May (authors). U.S. Department of the Interior, Geological Survey. (HA 143, 1964, HA 202, 1965). Hydrologic Investigations Atlases for Carol Stream, Scale 1:24,000, Contour Interval 10 feet. U.S. Department of the Interior, Geological Survey. (1964). Hydrologic Investigations Atlas, HA-87, Floods in the Palatine Area Floods in the Palatine Area. Howard E. Allen and others (authors). U.S. Department of the Interior, Geological Survey. (1964 and 1965). Hydrologic Investigation Atlases, HA-143 and HA-148. U.S. Department of the Interior, Geological Survey. (1963). Floods in Aurora North Quadrangle, Illinois, Hydrologic Investigations Atlas, HA-70.

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U.S. Department of the Interior, Geological Survey. (Hinsdale, Illinois, 1963, Photorevised 1972; Wheaton, Illinois, 1962, Photorevised 1972). Map of Flood-Prone Areas, Scale 1:24,000, Contour Interval 20 Feet. U.S. Department of the Interior, Geological Survey. (Elmhurst, Illinois, 1963, photorevised 1972 and 1980). 7.5-Minute Series Topographic Maps, Scale 1:24,000, Contour Interval 10 feet. U.S. Department of the Interior, Geological Survey. (Hinsdale Quadrangle, Illinois, 1963). Hydrologic Investigations Atlas, HA-86, Scale 1:24,000, Contour Interval 10 Feet. U.S. Department of the Interior, Geological Survey. (Sag Bridge Quadrangle, Illinois, 1963). Hydrologic Investigations Atlas, HA-149, Scale 1:24,000, Contour Interval 5 Feet. U.S. Department of the Interior, Geological Survey. (1962 to present). St. Charles Gage Station, No. 05551220. U.S. Water Resources Council. (March 1976). Bulletin No. 17, Guidelines for Determining Flood Flow Frequency. U.S. Water Resources Council, (December 1967). A Uniform Technique for Determining Flood Flow Frequencies, Bulletin No. 15. Village of Carol Stream, Village Hall. (January 1980). Carol Stream 1979 Census. Village of Bloomingdale, DuPage County, Illinois. (March 24, 1975). 75-10, An Ordinance Regulating the Interference with Storm Ditches and Requiring a Permit Therefore. Village of Willowbrook. (1974). Zoning Map. Village of Bloomingdale, DuPage County, Illinois. (June 1973). 73-19, An Ordinance Providing Stormwater Retention Requirements. “Wheaton Experiences Much Loss.” (October 11, 1954). The Daily Journal, Volume 22, No. 107, page 1. Wight Consulting Engineers, Inc. (1978). Surface Water Drainage Study, Indian Lakes Subdivision and Environs. Bloomingdale, Illinois. Wight and Company. (1977). Stormwater Management Study, Village of Willowbrook.

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Woodward, Sherman M. and Chesley I. Posey. (1941). Hydraulics of Steady Flow in Open Channels. John Wiley and Sons.

Exhibit 2 Note: The Flood Insurance Rate Map and its Index are separate documents. Contact the Map Repository at Dept. of Engineering County of DuPage, IL 421 N. County Farm Rd. Wheaton, IL 60187-3978 630.407.6700 voice 630.407.6701 fax

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