and incorporated areas - georgia dfirm · and incorporated areas community community name number...
TRANSCRIPT
COWETA COUNTY
COWETA COUNTY, GEORGIA
AND INCORPORATED AREAS Community Community Name Number COWETA COUNTY (UNINCORPORATED AREAS) 130298 GRANTVILLE, CITY OF 130443 HARALSON, TOWN OF 130299 MORELAND, TOWN OF 130300 NEWNAN, CITY OF 130062 SENOIA, CITY OF 130301
∗SHARPSBURG, TOWN OF 130581 TURIN, TOWN OF 130475
∗ Non-Floodprone
Revised: February 6, 2013
FLOOD INSURANCE STUDY NUMBER 13077CV001B
VOLUME 1 OF 2
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) report may not contain all
data available within the Community Map Repository. Please contact the
Community Map Repository for any additional data.
The Federal Emergency Management Agency (FEMA) may revise and republish
part or all of this FIS report at any time. In addition, FEMA may revise part of
this FIS report by the Letter of Map Revision process, which does not involve
republication or redistribution of the FIS report. Therefore, users should consult
with community officials and check the Community Map Repository to obtain the
most current FIS report components.
Initial Countywide FIS Effective Date: May 16, 2006
Revised Countywide FIS Effective Date: February 6, 2013
i
TABLE OF CONTENTS
Volume 1
1.0 INTRODUCTION..................................................................................................1
1.1 Purpose of Study ..............................................................................................1
1.2 Authority and Acknowledgements ..................................................................1
1.3 Coordination ....................................................................................................2
2.0 AREA STUDIED ...................................................................................................3
2.1 Scope of Study .................................................................................................3
2.2 Community Description ...................................................................................6
2.3 Principal Flood Problems .................................................................................7
2.4 Flood Protection Measures ..............................................................................7
3.0 ENGINEERING METHODS ...............................................................................8
3.1 Hydrologic Analyses ........................................................................................8
3.2 Hydraulic Analyses ........................................................................................23
3.3 Vertical Datum ...............................................................................................25
4.0 FLOODPLAIN MANANGEMENT APPLICATIONS....................................26
4.1 Floodplain Boundaries ...................................................................................26
4.2 Floodways ......................................................................................................27
5.0 INSURANCE APPLICATIONS.........................................................................67
6.0 FLOOD INSURANCE RATE MAP ..................................................................67
7.0 OTHER STUDIES ...............................................................................................68
8.0 LOCATION OF DATA .......................................................................................68
9.0 BIBLIOGRAPHY AND REFERENCES ..........................................................68
ii
TABLE OF CONTENTS
Volume 1 (continued)
FIGURES
Figure 1 – Floodway Schematic........................................................................................... 28
TABLES
Table 1 – Streams Studied by Detailed Methods .................................................................... 3
Table 2 – Stream Name Changes ........................................................................................... 5
Table 3 – Summary of Discharges ....................................................................................... 10
Table 4 – Manning’s “n” Values .......................................................................................... 24
Table 5 – Vertical Datum Conversion .................................................................................. 25
Table 6 – Floodway Data Table ........................................................................................... 29
Table 7 – Community Map History ..................................................................................... 69
EXHIBITS
Exhibit 1 - Flood Profiles
Chandlers Creek Panels 01P-04P
Chattahoochee River Panels 05P-07P
Keg Creek Panels 08P-09P
Lake Amlajack Creek Panels 10P-11P
Lake Summergrove Branch Panel 12P
Line Creek Panels 13P-22P
Little Creek Panels 23P-24P
Little Wahoo Creek Panels 25P-28P
Mineral Spring Branch Panels 29P-33P
Paradise Lakes Branch Panels 34P-35P
Peeks Creek Panel 36P
Persimmon Creek Panels 37P-39P
Sandy Creek Panels 40P-45P
Shoal Creek Panels 46P-50P
Snake Creek Panels 51P-54P
Tributary 1 to Line Creek Panels 55P-56P
Tributary 1 to Mineral Spring Branch Panels 57P-60P
iii
TABLE OF CONTENTS
Volume 2
EXHIBITS (continued)
Exhibit 1 - Flood Profiles
Tributary 1 to Persimmon Creek Panels 61P-62P
Tributary 1 to Sandy Creek Panels 63P-64P
Tributary 1 to Shoal Creek Panel 65P
Tributary 1 to Snake Creek Panel 66P
Tributary 1 to Turkey Creek Panel 67P
Tributary 1 to Wahoo Creek Panel 68P
Tributary 1 to White Oak Creek Panels 69P-70P
Tributary 2 to Mineral Spring Branch Panels 71P-74P
Tributary 2 to Sandy Creek Panels 75P-76P
Tributary 2 to Shoal Creek Panels 77P-78P
Tributary 2 to Snake Creek Panel 79P
Tributary 2 to Wahoo Creek Panels 80P-81P
Tributary 3 to Sandy Creek Panels 82P-83P
Tributary 3 to Shoal Creek Panels 84P- 85P
Tributary 3 to Wahoo Creek Panel 86P
Tributary 4 to Wahoo Creek Panel 87P
Tributary 5 to Wahoo Creek Panel 88P
Tributary 6 to Wahoo Creek Panel 89P
Tributary 7 to Wahoo Creek Panel 90P
Tributary 8 to Wahoo Creek Panel 91P
Tributary 9 to Wahoo Creek Panel 92P
Tributary 10 to Wahoo Creek Panel 93P
Tributary 11 to Wahoo Creek Panel 94P
Tributary 12 to Wahoo Creek Panel 95P
Turkey Creek Panels 96P-101P
Wahoo Creek Panels 102P-114P
White Oak Creek Panels 115P-120P
Exhibit 2 - Flood Insurance Rate Map Index
Flood Insurance Rate Map
1
FLOOD INSURANCE STUDY
COWETA COUNTY, GEORGIA AND INCORPORATED AREAS
1.0 INTRODUCTION
1.1 Purpose of Study
This Flood Insurance Study (FIS) revises and updates information on the
existence and severity of flood hazards in the geographic area of Coweta County,
including the Cities of Grantville, Newnan, and Senoia; the Towns of Haralson,
Moreland, Sharpsburg, and Turin; and the unincorporated areas of Coweta County
(referred to collectively herein as Coweta County), and aids in the administration
of the National Flood Insurance Act of 1968 and the Flood Disaster Protection
Act of 1973. This study has developed flood-risk data for various areas of the
community that will be used to establish actuarial flood insurance rates and to
assist the community in its efforts to promote sound floodplain management.
Minimum floodplain management requirements for participation in the National
Flood Insurance Program (NFIP) are set forth in the Code of Federal Regulations
at 44 CFR, 60.3.
Please note that the Town of Corinth was previously shown as geographically
located in Heard and Coweta Counties. The Town of Corinth has been absorbed
into the unincorporated areas of Heard and Coweta Counties. The portion
previously located in Coweta County, absorbed by this county, is included in this
FIS report. See the Heard County FIS report and Flood Insurance Rate Map
(FIRM) for flood-hazard information for the portion of Corinth absorbed by Heard
County.
The City of Palmetto is located geographically in Coweta County and Fulton
County. Also, the City of Palmetto is included, in its entirety, in the Fulton
County, GA FIS report. The Town of Corinth is located geographically in
Coweta County and Heard County. The FIS reports and Flood Insurance Rate
Maps (FIRMs) are printed separately. The Town of Haralson is geographically
located in Coweta County and Meriwether County. The Town of Haralson is
included in its entirety in this FIS report. Please note that the Town of Sharpsburg
is non-floodprone.
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, the more restrictive criteria take precedence and the
State (or other jurisdictional agency) will be able to explain them.
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.
2
The hydrologic and hydraulic analyses for the May 15, 1978 FIS report for the
City of Newnan (FIA, 1978) were performed by Roy F. Weston, Inc., for the U.S.
Department of Housing and Urban Development, Federal Insurance
Administration (FIA), under Contract No. H-4048. The work was completed in
October 1977.
The hydrologic and hydraulic analyses for the FIS report for the unincorporated
areas of Coweta County, dated February 2, 1982 (FEMA, 1982), were performed
by Roy F. Weston, Inc., for the Federal Emergency Management Agency
(FEMA), under Contract No. H-4048. The work was completed in July 1980.
For the September 8, 1999 revision (FEMA, 1999), the hydrologic and hydraulic
analyses for White Oak Creek were prepared by Braswell Engineering, Inc., for
FEMA, under Contract No. EMW-93-C-4147. The work was completed in
October 1997.
The digital FIRM conversion for the initial countywide FIS report, dated May 16,
2006 (FEMA, 2006), was performed by the Georgia Department of Natural
Resources, under contract number EMA-2003-GR-5369. The work was
completed in April 2005.
For this revised countywide FIS, the hydrologic and hydraulic analyses were
performed by Dewberry and Davis LLC for FEMA, under Contract No.
EMA-2009-CA-5930. Detailed hydrologic and hydraulic analyses were
performed for the Chattahoochee River and approximately 37 miles of stream
within the Wahoo Creek sub-basin. All non-revised detailed study streams were
redelineated. Limited detailed/approximate hydrologic and hydraulic analyses
were performed for all Zone A and shaded Zone X floodplains. This work was
completed in July 2011.
Base map information shown on this FIRM was derived from Coweta County
aerial photography produced at a scale of 1:600 from photography dated 2009.
The coordinate system used for the production of the digital FIRM is State Plane
Coordinate System Georgia West Zone (FIPS zone 1002) based on Transverse
Mercator projection. The horizontal datum is North American Datum of 1983.
The use of the base map is restricted by the data agreement between Coweta
County and the Study Contractor.
1.3 Coordination
For the 1978 FIS report for the City of Newnan, the final Consultation
Coordination Officer (CCO) meeting was held on November 1, 1977, and was
attended by representatives of the FIA, Roy F. Weston, Inc., city officials, and
local residents (FIA, 1978).
For the 1982 FIS report for the unincorporated areas of Coweta County, an initial
Coordination meeting was held on July 7, 1978, and a final CCO meeting was
held on September 10, 1981. Both meetings were attended by representatives of
FEMA, Coweta County, and Roy F. Weston, Inc. (FEMA, 1982).
3
For the 1999 revision, the county was notified by a letter dated December 1, 1997,
that its FIS would be revised using the analysis prepared by Braswell
Engineering, Inc. (FEMA, 1999).
For the May 16, 2006, countywide FIS report, the initial scoping meeting was
held on September 23, 2004, and the final CCO meeting was held on May 5,
2005. Both meetings were attended by representatives of FEMA, the Georgia
Department of Natural Resources, and local communities.
For this revised countywide FIS report, a scoping meeting was held on April 16,
2010, and was attended by representatives of FEMA, the Georgia Department of
Natural Resources, local communities, and Dewberry and Davis LLC. The
purpose of this meeting was to discuss the scope of the FIS.
The results of this study were reviewed at the final CCO meeting held on October
27, 2011 and attended by representatives of FEMA, local communities, and
Dewberry and Davis LLC. All problems raised at that meeting have been
addressed.
2.0 AREA STUDIED
2.1 Scope of Study
This FIS covers the geographic area of Coweta County, Georgia, including the
incorporated communities listed in Section 1.1. The areas studied by detailed
methods were selected with priority given to all known flood hazard areas and
areas of projected development or proposed construction.
The following table lists the flooding sources that have been studied by detailed
methods and are included in this FIS report:
Table 1 – Streams Studied by Detailed Methods
Chandlers Creek Tributary 1 to Wahoo Creek
Chattahoochee River Tributary 1 to White Oak Creek
Keg Creek Tributary 2 to Mineral Spring Branch
Lake Amlajack Creek Tributary 2 to Sandy Creek
Lake Summergrove Branch Tributary 2 to Shoal Creek
Line Creek Tributary 2 to Snake Creek
Little Creek Tributary 2 to Wahoo Creek
Little Wahoo Creek Tributary 3 to Sandy Creek
Mineral Spring Branch Tributary 3 to Shoal Creek
Paradise Lakes Branch Tributary 3 to Wahoo Creek
Peeks Creek Tributary 4 to Wahoo Creek
Persimmon Creek Tributary 5 to Wahoo Creek
4
Table 1 – Streams Studied by Detailed Methods
Sandy Creek Tributary 6 to Wahoo Creek
Shoal Creek Tributary 7 to Wahoo Creek
Snake Creek Tributary 8 to Wahoo Creek
Tributary 1 to Line Creek Tributary 9 to Wahoo Creek
Tributary 1 to Mineral Spring Branch Tributary 10 to Wahoo Creek
Tributary 1 to Persimmon Creek Tributary 11 to Wahoo Creek
Tributary 1 to Sandy Creek Tributary 12 to Wahoo Creek
Tributary 1 to Shoal Creek Turkey Creek
Tributary 1 to Snake Creek Wahoo Creek
Tributary 1 to Turkey Creek White Oak Creek
The limits of detailed study are indicated on the Flood Profiles (Exhibit 1) and on
the FIRM (Exhibit 2).
For this countywide revision, the Chattahoochee River received a new detailed
study and the following streams were restudied by detailed methods:
Little Wahoo Creek Tributary 6 to Wahoo Creek
Snake Creek Tributary 7 to Wahoo Creek
Tributary 1 to Snake Creek Tributary 8 to Wahoo Creek
Tributary 1 to Wahoo Creek Tributary 9 to Wahoo Creek
Tributary 2 to Snake Creek Tributary 10 to Wahoo Creek
Tributary 2 to Wahoo Creek Tributary 11 to Wahoo Creek
Tributary 3 to Wahoo Creek Tributary 12 to Wahoo Creek
Tributary 4 to Wahoo Creek Wahoo Creek
Tributary 5 to Wahoo Creek
This countywide revision incorporates the following Letter of Map Revision:
Case Number Determination Date Flooding Source
11-04-0184P April 22, 2011 Keg Creek
For this countywide revision, non-restudied reaches of streams that have been
studied by detailed methods were selected for redelineation based on more recent
topography. The topographic data source utilized for this study is contours
provided by the Coweta County Geographic Information System (GIS)
Department. The contours were created based on countywide topographic Light
Detection and Ranging (LiDAR) data acquired by Photo Science, Inc. in 2007
(Photo Science, 2007). The LiDAR data met the vertical and horizontal accuracy
requirements in FEMA’s Guidelines for Aerial Mapping and Surveying (FEMA,
2003).
5
The following streams were redelineated:
Chandlers Creek Tributary 1 to Persimmon Creek
Lake Amlajack Creek Tributary 1 to Sandy Creek
Lake Summergrove Branch Tributary 1 to Shoal Creek
Line Creek Tributary 1 to Turkey Creek
Little Creek Tributary 1 to White Oak Creek
Mineral Spring Branch Tributary 2 to Mineral Spring Branch
Paradise Lakes Branch Tributary 2 to Sandy Creek
Peeks Creek Tributary 2 to Shoal Creek
Persimmon Creek Tributary 3 to Sandy Creek
Sandy Creek Tributary 3 to Shoal Creek
Shoal Creek Turkey Creek
Tributary 1 to Line Creek White Oak Creek
Tributary 1 to Mineral Spring Branch
Limited detailed analyses/approximate analyses were used to study those areas
having low development potential or minimal flood hazards. The scope and
methods of study were proposed to and agreed upon by Coweta County. The
limited detail studies were incorporated into the FIRMs as Zone A for reaches
where Zone A exists on the initial countywide FIRM; and as shaded Zone X for
reaches where Zone A does not exist on the initial countywide FIRM.
Approximate studies were incorporated into the FIRMs as Zone A.
No stream name change was made for this FIS report. For the May 16, 2006,
countywide FIS report, in the process of combining the FIS reports for the City of
Newnan and Coweta County, the designated names for the numbered tributaries
were revised to avoid duplicate names and for general clarity. Table 2, “Stream
Name Changes” lists the numbered tributaries with their current and revised
names, along with the community FIS report where it was located originally.
Table 2 – Stream Name Changes Community Old Name Current Name
(Revised by initial county wide FIS)
City of Newnan Tributary 1 Tributary 1 to Wahoo Creek
Tributary 2 Tributary 2 to Wahoo Creek
Tributary 3 Tributary 3 to Wahoo Creek
Tributary 4 Tributary 4 to Wahoo Creek
Tributary 5 Tributary 5 to Wahoo Creek
Tributary 6 Tributary 6 to Wahoo Creek
Tributary 7 Tributary 7 to Wahoo Creek
Tributary 8 Tributary 8 to Wahoo Creek
Tributary 9 Tributary 9 to Wahoo Creek
6
Table 2 – Stream Name Changes (continued)
Community Old Name Current Name
(Revised by initial county wide FIS)
City of Newnan Tributary 10 Tributary 10 to Wahoo Creek
Tributary 11 Tributary 11 to Wahoo Creek
Tributary 12 Tributary 12 to Wahoo Creek
Tributary 13 Tributary 1 to Snake Creek
Tributary 14 Tributary 2 to Snake Creek
Tributary 15 Tributary 1 to Mineral Spring Branch
Tributary 16 Tributary 2 to Mineral Spring Branch
Coweta County
(Unincorporated Areas) Tributary 1 Tributary 1 to Wahoo Creek
Tributary 2 Tributary 1 to Mineral Spring Branch
Tributary 3 Tributary 2 to Mineral Spring Branch
Tributary 4 Tributary 1 to Sandy Creek
Tributary 5 Tributary 3 to Sandy Creek
Tributary 6 Tributary 2 to Sandy Creek
Tributary 7 Tributary 1 to Line Creek
Tributary 8 Tributary 1 to Shoal Creek
Tributary 9 Tributary 2 to Shoal Creek
Tributary 10 Tributary 3 to Shoal Creek
Tributary 11 Tributary 1 to Persimmon Creek
Tributary 12 Tributary 1 to Turkey Creek
Tributary 13 Tributary 1 to White Oak Creek
2.2 Community Description
Coweta County is located in the northwestern portion of Georgia and
encompasses an area of approximately 443 square miles. It is bordered by Carroll
and Fulton Counties to the north, Fayette and Spaulding Counties to the east,
Meriwether and Troupe Counties to the south, and Heard County to the west. The
population of Coweta County in 2010 was reported to be 127,317 (2010 U.S.
Census).
The climate of Coweta County is characterized by warm summers, mild winters,
and moderate to heavy rainfall. Summer and winter temperatures range from an
average high of 90 degrees Fahrenheit ( ̊F) in July to an average low of 34 ̊F in
January. The average annual precipitation is approximately 51 inches.
7
The topography of the area is typical of the Piedmont Region of Georgia in that
the land consists of gently rolling hills with steep slopes near the many streams
flowing throughout the area. The soils belong to three major groupings: The
Davidson-Cecil-Madison Association, the Mecklenburg-Iredell-Wilkes
Association, and the Chewacla-Augusta Association. The soils range from well
drained to poorly drained. The nearly level soils of the Chewacla-Augusta
Association are located in frequently flooded bottom lands and low stream
terraces. Because of the flooding hazard, development in these areas is limited
(FEMA, 1999).
2.3 Principal Flood Problems
Coweta County has a history of moderate flooding. Flooding in Coweta County
is due to a relatively high rate of runoff, flat floodplains, and intermittently
clogged and crooked stream channels. Most floods occur during the annual
planting, growing, and harvesting seasons. Floodwater is a major problem to the
county and state in maintaining roads and bridges. Traffic is occasionally
interrupted and is detoured around flooded crossings.
Coweta County has two U.S. Geological Survey (USGS) stream gages: 02344620
Shoal Creek near Sharpsburg (discharge records since 2007); and 02344700 Line
Creek near Senoia (discharge records since 1964).
Most recently, extensive flooding occurred in Coweta County following the
historical flooding event of September 2009, when the Chattahoochee River
reached a record high flood stage of 29.74 feet at Whitesburg. During the
September 2009 storm, much of the flood losses can be attributed to the
backwater effects of the Chattahoochee River.
2.4 Flood Protection Measures
No major flood protection measures exist in Coweta County.
A floodplain damage prevention ordinance has been enacted by Coweta County to
protect, maintain, and enhance the public health, safety, environment, and general
welfare and to minimize public and private losses due to flood conditions in flood
hazard areas. The ordinance also protects the beneficial uses of floodplain areas
for water quality protection, streambank and stream corridor protection, wetlands
preservation, and ecological and environmental protection (The Zoning and
Development Ordinance of Coweta County, Georgia, effective February 1995).
The City of Newnan has a zoning ordinance that designates Flood Hazard Districts
and limits the use of such floodplain lands (The Zoning Ordinance of the City of
Newnan, Georgia, effective November 2000).
8
3.0 ENGINEERING METHODS
For the flooding sources studied by detailed methods in the community, standard
hydrologic and hydraulic study methods were used to determine the flood hazard data
required for this study. 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 1-percent-annual-chance (100-year) flood in any 50-year
period is approximately 40 percent (4 in 10); 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 community at the time of completion of this
study. Maps and flood elevations will be amended periodically to reflect future changes.
3.1 Hydrologic Analyses
Hydrologic analyses were carried out to establish peak discharge-frequency
relationships for each flooding source studied by detailed methods affecting the
community.
May 16, 2006, Countywide Analyses
Flood-flow frequency data for the 10-, 2-, and 1-percent-annual-chance floods for
all streams studied by detailed methods, except for Line Creek and White Oak
Creek, were estimated using the method for small natural streams in Georgia
(USGS, 1976) and the method for small urban watersheds in the Metropolitan
Atlanta Area (USGS, unpublished). The latter method was selected because it
allows the applicable rural regional-frequency relations to be adjusted for
urbanized conditions, such as those found in Newnan. The
0.2-percent-annual-chance flood flow was extrapolated from the 10-, 2-, and
1-percent-annual-chance flows on log-log paper.
Discharge-frequency values for Line Creek were estimated using U.S. Soil
Conservation Service (SCS) methodology, as described in Technical Release 55
(USDA, 1975) and the computer program TR-20 (USDA, 1965).
Peak discharges for White Oak Creek were estimated using USGS urban
regression equations (USGS, 1995). Basin drainage areas were delineated and
planimetered on USGS 7.5-Minute Series topographic maps. Impervious area for
each basin was estimated based on aerial tax maps, USGS quadrangle maps, and
field observation.
9
February 6, 2013 Countywide Analyses
This countywide revision incorporates a new detailed study for the Chattahoochee
River from Buford Dam downstream to the headwater of West Point Lake just
above the Heard County and Troup County boundaries. For the reach from the
Roswell gage downstream to the headwater of West Point Lake, discharges were
determined based on a logarithmic discharge – area relationship derived based on
flood-frequency analysis at selected gaging stations. Since Lake Lanier reached
its normal elevation in 1959, flood frequency analysis was performed for six
selected gages that have a minimum of 10 years of flood records from 1960 to
2009. Since the logarithms of the peak discharges were reasonably consistent with
Pearson Type III distribution, flood frequency analysis was performed based on
Bulletin 17B guidelines (IACWD, 1982).
For this revision, peak discharge-frequency relationships for the streams restudied
by detailed methods were determined using the U.S. Army Corps of Engineers
(USACE) HEC-HMS Version 3.4 computer program.
The 24-hour rainfall depths for 50-, 20-, 10-, 4-, 2-, 1-percent-annual-chance
events were determined based on National Weather Service Technical Paper 40
(U.S. Weather Bureau, 1961) and were extrapolated to the 0.2-percent-annual-
chance event. The SCS Type II storm distribution for 24-hour duration was
applied to each storm event (USDA, 1986).
Runoff volumes were calculated using the Natural Resources Conservation
Service (NRCS) Runoff Curve Number method documented in NRCS Technical
Reference 55 (TR-55) (USDA, 1986). Average antecedent moisture conditions
(AMC II) was assumed. Curve number was determined based on soil data
obtained from the NRCS Soil Survey Geographic database and existing land use
data created based on aerial imagery.
The hydrographs for sub-basins were developed based on the NRCS unit
hydrograph method (USDA, 2007). The lag time of each sub-basin was
determined based on the methods presented in TR-55.
Hydrograph routing to account for the attenuation of flows in open channel
segments was performed using the Muskingum-Cunge routing method. The
model parameters include reach length, roughness coefficients, energy grade, and
representative channel cross section for each reach. Energy grade was estimated
as the channel bed slope based on the LiDAR topographic data. A representative
cross section was assigned to each reach and the station/elevation data was
extracted from the topographic data and simplified to eight points.
For this revision, peak discharge-frequency relationships for the streams studied
by limited detailed methods were determined using the USACE HEC-HMS
Version 3.3 computer program.
10
For this revision, peak discharge-frequency relationships for the streams studied
by approximate methods were determined using regional regression equations for
rural areas in Georgia (USGS, 2009) and for urban areas in Georgia (USGS,
1999).
Peak discharge-drainage area relationships for all detailed studied streams are
shown in Table 3, “Summary of Discharges.”
Table 3 - Summary of Discharges
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage
Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
CHANDLERS CREEK
At confluence with
White Oak Creek
5.20 1,330 2,080 2,400 2,880
CHATTAHOOCHEE
RIVER
At Coweta/ Heard
County boundary
2,528.00 44,820 59,866 66,378 82,143
At State Highway 16 2,430.00 43,387 57,897 64,170 79,342
KEG CREEK
Just upstream of
Rockaway Road
14.50 * * 4,806 *
LAKE AMLAJACK
CREEK
At confluence with
White Oak Creek
2.79 970 1,500 1,740 2,100
LAKE
SUMMERGROVE
BRANCH
At confluence with
White Oak Creek
2.76 910 1,430 1,670 1,980
LINE CREEK
Approximately 2,350
feet downstream of
Rockaway Road
101.00 11,680 18,900 20,560 27,900
11
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage
Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
LINE CREEK (cont’d)
Approximately 5,000
feet upstream of the
confluence of Flat
Creek
74.50 9,760 15,800 17,200 23,380
Approximately 4,500
feet downstream of
the confluence of
Tributary 1 to Line
Creek
70.20 9,350 15,100 16,400 22,330
Approximately 6,500
feet upstream of the
confluence of Shoal
Creek
40.80 5,920 9,680 10,180 14,420
Just downstream of the
confluence of Little
Creek
30.51 4,600 7,860 8,640 14,080
Approximately 2,900
feet upstream of the
confluence of Little
Creek
29.59 4,480 7,660 8,430 11,780
Approximately 8,500
feet upstream of the
confluence of Little
Creek
27.94 4,275 7,320 8,040 11,250
Approximately 3,000
feet downstream of
Palmetto Tyrone
Road
26.29 4,070 6,970 7,660 10,720
At Palmetto Tyrone
Road
25.79 4,010 6,860 7,550 10,560
Approximately 3,300
feet upstream of
Palmetto Tyrone
Road
23.84 3,760 6,460 7,100 9,940
Just downstream of the
confluence of
Persimmon Creek
22.44 3,590 6,160 6,770 9,480
Approximately 2,300
feet downstream of
Collingsworth Road
11.17 2,180 3,780 4,150 5,830
12
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
LINE CREEK (cont’d)
At Collingsworth Road 9.40 1,900 3,400 3,800 5,000
Approximately 2,100
feet upstream of
Weldon Road
4.21 1,300 2,250 2,500 3,420
LITTLE CREEK
At confluence with Line
Creek
4.60 1,350 2,265 2,420 3,430
Approximately 2,900
feet upstream of
Minix Road
3.88 1,220 2,250 2,350 3,220
Approximately 4,600
feet downstream of
Major Road
2.90 990 1,720 1,900 2,600
At Major Road 1.84 690 1,220 1,350 1,850
Approximately 1,400
feet upstream of
Major Road
1.12 480 850 940 1,300
Approximately 1,500
feet downstream of
Shaw Road
0.77 370 630 710 980
LITTLE WAHOO
CREEK
At confluence with
Wahoo Creek
5.33 1,290 2,027 2,258 2,953
At Roscoe Road 4.09 1,241 1,946 2,166 2,830
Approximately 6,300
feet upstream of
Roscoe Road
3.28 1,229 1,930 2,148 2,841
Approximately 3,000
feet downstream of
Golf Club Drive
2.08 1,146 1,797 1,996 2,565
MINERAL SPRING
BRANCH
At confluence with
Mountain Creek
4.30 1,640 2,400 2,730 3,600
13
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
MINERAL SPRING
BRANCH (cont’d)
Approximately 2,700
feet upstream of the
confluence of
Tributary 1 to Mineral
Spring Branch
3.00 1,320 1,940 2,210 2,910
Approximately 3,800
feet downstream of
Belk Road
2.30 1,170 1,170 1,950 2,580
At Belk Road 1.15 810 1,180 1,340 1,770
At Colonial Drive 0.76 680 980 1,110 1,480
At Fourth Street 0.34 430 620 710 950
PARADISE LAKES
BRANCH
At confluence with
White Oak Creek
5.52 1,380 2,150 2,480 2,900
PEEKS CREEK
At confluence with Line
Creek
7.12 1,960 3,370 3,710 5,200
Approximately 2,800 feet
upstream of
Collingsworth Road
6.51 1,800 3,150 3,420 4,700
PERSIMMON CREEK
At confluence with Line
Creek
4.15 1,290 2,210 2,430 3,390
Approximately 900 feet
upstream of the
confluence of
Tributary 1 to
Persimmon Creek
3.68 1,190 2,040 2,240 3,100
Approximately 3,200
feet downstream of
Cannongate Road
3.14 1,050 1,820 2,000 2,760
At Cannongate Road 1.97 740 1,300 1,420 1,980
14
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage
Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-Chance
SANDY CREEK
Approximately 1,200 feet
downstream of
Holbrook Road
16.32 2,610 4,040 4,620 6,540
Approximately 400 feet
upstream of
Holbrook Road
14.94 2,480 3,830 4,390 6,200
Approximately 200 feet
downstream of the
confluence of
Tributary 3 to Sandy
Creek
7.40 1,730 2,650 3,050 4,325
Approximately 7,800
feet downstream of
Old Corinth Road
5.90 1,510 2,330 2,680 3,780
Approximately 2,300
feet downstream of
Old Corinth Road
5.10 1,380 2,140 2,460 3,460
At Old Corinth Road 3.99 1,260 1,930 2,220 3,150
Approximately 5,300
feet upstream of Old
Corinth Road
3.42 1,150 1,760 2,030 2,875
Approximately 4,100
feet downstream of
Waterworks Road
2.84 1,030 1,580 1,820 2,580
Approximately 2,300
feet downstream of
Waterworks Road
2.14 870 1,340 1,550 2,180
Approximately 1,100
feet downstream of
Waterworks Road
0.71 520 780 900 1,300
At Alpine Drive 0.10 140 220 270 350
SHOAL CREEK
At confluence with Line
Creek
27.06 3,910 6,610 7,250 10,100
Approximately 4,800 feet
upstream of the
confluence with Line
Creek
26.49 3,860 6,530 7,170 9,995
15
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
SHOAL CREEK
(cont’d)
Approximately 3,600
feet downstream of
State Highway 54
24.65 3,720 6,300 6,920 9,640
Approximately 1,000
feet downstream of
Lower Fayetteville
Road
17.25 3,130 5,360 5,880 8,210
Approximately 2,600
feet upstream of State
Highway 34
15.01 2,880 4,940 5,420 7,570
Just downstream of the
confluence of
Tributary 2 to Shoal
Creek
11.76 2,470 4,230 4,650 6,500
Approximately 2,500
feet upstream of the
confluence of
Tributary 2 to Shoal
Creek
7.76 1,950 3,360 3,700 5,180
Just downstream of the
confluence of
Tributary 3 to Shoal
Creek
6.57 1,800 3,110 3,420 4,800
Approximately 1,700
feet downstream of
Raymond Hill Road
5.44 1,575 2,750 3,000 4,200
Just downstream of
Raymond Hill Road
4.32 1,320 2,320 2,550 3,520
At Raymond Hill Road 3.56 1,150 2,000 2,150 3,000
Approximately 6,500
feet upstream of
Raymond Hill Road
3.15 1,050 1,825 2,000 2,760
SNAKE CREEK
At confluence with
Wahoo Creek
3.21 1,332 2,059 2,272 3,064
16
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
SNAKE CREEK
(cont’d)
Approximately 7100
feet upstream of the
confluence with
Wahoo Creek
2.32 1,420 2,110 2,321 2,933
At Hospital Road 1.09 1,699 2,551 2,817 3,548
Just upstream of the
confluence of
Tributary 1 to Snake
Creek
0.63 1,048 1,548 1,703 2,127
Just upstream of the
confluence of
Tributary 2 to Snake
Creek
0.37 608 896 982 1,226
TRIBUTARY 1 TO
LINE CREEK
At the confluence with
Line Creek
2.56 940 1,630 1,790 2,510
Approximately 9,000
feet downstream of
Christopher Road
2.40 850 1,500 1,650 2,280
Approximately 3,500
feet downstream of
Christopher Road
2.02 740 1,300 1,420 1,980
Just downstream of
Christopher Road
1.65 640 1,125 1,250 1,725
TRIBUTARY 1 TO
MINERAL SPRING
BRANCH
At confluence with
Mineral Spring Branch
1.02 670 1,000 1,150 1,470
Approximately 1,500 feet
upstream of Wallace
Gray Road
0.52 500 740 840 1,100
17
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
TRIBUTARY 1 TO
PERSIMMON CREEK
At confluence with
Persimmon Creek
0.41 330 560 620 870
TRIBUTARY 1 TO
SANDY CREEK
At confluence with
Sandy Creek
1.38 570
920 1,080 1,440
Approximately 100 feet
downstream of Old
Corinth Road
1.15 520 830 970 1,310
TRIBUTARY 1 TO
SHOAL CREEK
At confluence with Shoal
Creek
5.53 1,600 2,750 3,075 4,200
Approximately 2,300 feet
upstream of the
confluence of Shoal
Creek
5.46 1,575 2,725 3,050 4,150
TRIBUTARY 1 TO
SNAKE CREEK
At confluence with Snake
Creek
0.08 103 169 189 248
TRIBUTARY 1 TO
TURKEY CREEK
At confluence with
Turkey Creek
1.37 520 900 1,010 1,590
TRIBUTARY 1 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.43 323 484 534 692
At Millard Farmer
Industrial Boulevard
0.17 208 268 279 303
TRIBUTARY 1 TO
WHITE OAK CREEK
At confluence with White
Oak Creek
2.70 1,100 1,650 1,900 2,340
18
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
TRIBUTARY 2 TO
MINERAL SPRING
BRANCH
At confluence with
Mineral Spring
Branch
0.71 580 860 990 1,280
TRIBUTARY 2 TO
SANDY CREEK
At confluence with
Tributary 3 to
Sandy Creek
1.34 560 900 1,060 1,410
Approximately 2,500
feet upstream of
the confluence
with Tributary 3 to
Sandy Creek
0.20 180 300 360 450
TRIBUTARY 2 TO
SHOAL CREEK
At confluence with
Shoal Creek
4.27 1,330 2,300 2,525 3,475
Approximately
2,900 feet
upstream of the
confluence with
Shoal Creek
3.74 1,200 2,150 2,275 3,150
Approximately
1,900 feet
upstream of
Private Road to
McCollum-
Sharpsburg Road
2.98 1,000 1,750 1,900 2,650
TRIBUTARY 2 TO
SNAKE CREEK
At confluence with
Snake Creek
0.20 373 547 599 747
TRIBUTARY 2 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.80 724 1,019 1,102 1,333
19
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
TRIBUTARY 3 TO
SANDY CREEK
Approximately 100
feet downstream
of Old Corinth
Road
4.58 1,170 1,840 2,140 2,920
At Old Corinth
Road
3.24 950 1,510 1,760 2,380
Approximately
1,500 feet
downstream of
Potts Road
2.24 760 1,220 1,420 1,910
At Potts Road 1.27 550 880 1,030 1,370
TRIBUTARY 3 TO
SHOAL CREEK
At confluence with
Shoal Creek
1.13 485 850 940 1,300
Approximately
1,700 feet
downstream of
Raymond Hill
Road
0.60 230 410 450 600
TRIBUTARY 3 TO
WAHOO CREEK
At confluence with
Tributary 2 to
Wahoo Creek
0.28 134 192 205 240
TRIBUTARY 4 TO
WAHOO CREEK
At confluence with
Tributary 3 to
Wahoo Creek
0.12 108 192 219 298
TRIBUTARY 5 TO
WAHOO CREEK
At confluence with
Tributary 2 to
Wahoo Creek
0.03 31 55 62 85
20
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage
Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
TRIBUTARY 6 TO
WAHOO CREEK
At confluence with
Tributary 2 to
Wahoo Creek
0.04 32 58 67 92
TRIBUTARY 7 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.54 682 995 1,089 1,352
At Sprayberry Road 0.45 624 909 994 1,233
TRIBUTARY 8 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.16 319 457 498 613
TRIBUTARY 9 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.19 210 342 383 501
TRIBUTARY 10 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.14 147 239 267 349
TRIBUTARY 11 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.49 728 1,071 1,173 1,463
TRIBUTARY 12 TO
WAHOO CREEK
At confluence with
Wahoo Creek
0.34 516 763 837 1,046
21
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location
Drainage
Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
TURKEY CREEK
At confluence with
White Oak Creek
6.43 1,840 2,740 3,130 3,980
WAHOO CREEK
At confluence with the
Chattahoochee River
34.86 5,141 8,034 9,022 12,080
Approximately 700 feet
downstream of Welcome
Sergeant Road
26.71 4,963 7,792 8,770 11,736
Just upstream of the
confluence of Snake
Creek
16.33 4,096 5,980 6,652 8,706
Just upstream of the
confluence of Little
Wahoo Creek
10.93 2,931 4,169 4,604 5,944
At Roscoe Road 9.89 2,821 3,904 4,274 5,447
Approximately 5,000 feet
upstream of Roscoe Road
8.17 2,563 3,359 3,603 4,325
Just upstream of the
confluence of Tributary 1
to Wahoo Creek
6.90 2,317 2,791 2,926 3,302
At Millard Farmer Industrial
Boulevard
4.16 1,487 1,752 1,830 2,050
At Jefferson Street 3.56 2,706 3,650 3,948 4,673
Just upstream of the
confluence of Tributary 7
to Wahoo Creek
2.20 1,360 1,668 1,760 1,991
At Greison Trail 1.56 1,333 2,260 2,492 3,145
WHITE OAK
CREEK
At State Highway 54 64.88 7,830 11,900 13,870 18,630
At Gordon Road 54.74 7,070 10,720 12,480 16,720
At Cannon Road 43.42 6,060 9,180 10,680 14,300
At State Highway 16 36.80 5,480 8,280 9,630 12,860
At Norfolk Southern 31.58 5,060 7,620 8,840 11,770
At Goodynn Road 26.14 4,510 6,780 7,860 10,430
22
Table 3 - Summary of Discharges (continued)
Peak Discharges (cubic feet per second)
Flooding Source and
Location Drainage Area
(square miles)
10-Percent-
Annual-
Chance
2-Percent-
Annual-
Chance
1-Percent-
Annual-
Chance
0.2-Percent-
Annual-
Chance
WHITE OAK
CREEK (cont’d)
At Lower
Fayetteville Road
10.34 2,470 3,690 4,270 5,620
At State Highway 34 7.09 1,940 2,880 3,340 4,380
At Walt Sanders
Road
3.39 990 1,510 1,760 2,360
Approximately
2,600 feet
upstream of Walt
Sanders Road
1.78 650 990 1,150 1,540
At Interstate
Highway 85/State
Highway 403
1.12 440 680 790 1,070
*Data not available
23
3.2 Hydraulic Analyses
Analyses of the hydraulic characteristics of flooding from the sources 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 Table in the FIS
report. Flood elevations shown on the FIRM are primarily intended for flood
insurance rating purposes. For construction and/or floodplain management
purposes, users are cautioned to use the flood elevation data presented in the
initial countywide FIS report in conjunction with the data shown on the FIRM.
May 16, 2006, Countywide Analyses
Cross sections for the flooding sources studied by detailed methods were
obtained from field surveys and aerial photographs at a scale of 1:12,000 in the
county (Jack W. Berry & Associates, Inc., 1977a) and 1:1,000 in the City of
Newnan. All bridges, dams, and culverts were field surveyed to obtain elevation
data and structural geometry.
Water surface elevations for floods of the selected recurrence intervals were
computed using the USACE HEC-2 step-backwater computer program
(USACE, 1984). Starting water surface elevations were calculated using the
slope-area method.
Roughness factors (Manning’s “n”) used in the hydraulic computations were
based on field inspection and aerial photographs (Jack W. Berry & Associates,
Inc., 1977a). For the 1999 White Oak Creek revision, the values ranged from
0.035 to 0.050 for the channel and 0.030 to 0.100 for the overbanks. The values
for all other streams in the initial countywide FIS report ranged from 0.033 to
0.045 for the channels and 0.025 to 0.080 for the overbanks.
For streams studied by approximate methods, the Flood Hazard Boundary Maps
were field checked and the boundaries were revised where necessary (FIA,
1976).
February 6, 2013 Countywide Analyses
For this revision, cross sections for the flooding sources studied by detailed
methods were cut from the digital terrain model of the topographic LiDAR data
(Photo Science, 2009) at desired locations. Field survey information was
incorporated in the model where cross sections were surveyed. Field survey
information was used to supplement the channel information at cut cross sections
outside the areas where field surveys were obtained. All bridges, culverts, and
dams were field surveyed to obtain elevation data and structural geometry.
24
Water surface elevations for floods of the selected recurrence intervals were
computed using the USACE HEC-RAS Version 4.0 computer program.
Starting water surface elevations were determined using normal depth unless a
coincident peak situation is assumed. The energy slope was approximated by
using the average slope of the channel at the lower limits of the model. Under a
coincident peak situation, a known water surface elevation was implemented as
the starting water surface elevation.
Roughness factors (Manning’s “n”) used in the hydraulic computations were
chosen by engineering judgment and were based on field inspection and aerial
photographs. The Manning’s “n” values for all the detailed studied streams are
listed in Table 4, “Manning’s “n” Values.”
Table 4 – Manning’s “n” Values
Stream Channel “n” Overbank “n”
Chattahoochee River 0.033-0.053 0.078-0.112
Little Wahoo Creek 0.045-0.05 0.03-0.1
Snake Creek 0.05 0.03-0.1
Tributary 1 to Snake Creek 0.05 0.06-0.08
Tributary 1 to Wahoo Creek 0.035-0.05 0.035-0.12
Tributary 2 to Snake Creek 0.05 0.06-0.1
Tributary 2 to Wahoo Creek 0.05-0.055 0.03-0.12
Tributary 3 to Wahoo Creek 0.045-0.05 0.03-0.08
Tributary 4 to Wahoo Creek 0.045 0.05-0.08
Tributary 5 to Wahoo Creek 0.045 0.045-0.1
Tributary 6 to Wahoo Creek 0.035-0.055 0.035-0.08
Tributary 7 to Wahoo Creek 0.035-0.055 0.03-0.1
Tributary 8 to Wahoo Creek 0.05 0.03-0.1
Tributary 9 to Wahoo Creek 0.05 0.03-0.12
Tributary 10 to Wahoo Creek 0.05 0.035-0.1
Tributary 11 to Wahoo Creek 0.055 0.055-0.12
Tributary 12 to Wahoo Creek 0.045-0.055 0.03-0.08
Wahoo Creek 0.03-0.05 0.03-0.12
For streams studied by limited detailed and approximate methods, cross sections
were obtained using digital terrain model of the topographic LiDAR data (Photo
Science, 2009). For limited detail analyses, field measurements were made to
approximate the geometry for bridges and culverts in the hydraulic models.
Locations of selected cross sections used in the hydraulic analyses are shown on
the Flood Profiles (Exhibit 1). For stream segments for which a floodway was
computed (Section 4.2), selected cross section locations are also shown on the
FIRM (Exhibit 2).
25
The hydraulic analyses for this study were based on unobstructed flow. The
flood elevations shown on the Flood Profiles (Exhibit 1) are thus considered
valid only if hydraulic structures remain unobstructed, operate properly, and do
not fail.
3.3 Vertical Datum
All FIS reports 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 FIS reports and
FIRMs was the National Geodetic Vertical Datum 1929 (NGVD29). With the
finalization of the National American Vertical Datum of 1988 (NAVD88), many
FIS reports and FIRMs are being prepared using NAVD88 as the referenced
vertical datum.
All flood elevations shown in this FIS report and on the FIRM are referenced to
NAVD88. Structure and ground elevations in the community must, therefore, be
referenced to NAVD88. It is important to note that adjacent communities may
be referenced to NGVD29. This may result in differences in Base Flood
Elevations (BFEs) across the corporate limits between the communities. The
average conversion factor that was used to convert the data in the initial
countywide FIS report to NAVD88 was calculated using the National Geodetic
Survey’s VERTCON online utility (NGS, 2004). The data points used to
determine the conversion factor are listed in Table 5, “Vertical Datum
Conversion.”
Table 5-Vertical Datum Conversion
Quad Name Corner Latitude Longitude Conversion from
NGVD29 to
NAVD88
Whitesburg NE 33.50 84.88 0.105 feet
Newnan North NE 33.50 84.75 0.102 feet
Madras NE 33.50 84.62 0.105 feet
Whitesburg SW 33.38 85.00 0.131 feet
Whitesburg SE 33.38 84.88 0.085 feet
Newnan North SE 33.38 84.75 0.066 feet
Madras SE 33.38 84.62 0.059 feet
Newnan
Southwest
SE 33.25 84.88 0.043 feet
Newnan South SE 33.25 84.75 0.007 feet
Sharpsburg SE 33.25 84.62 0.013 feet
Senoia SE 33.25 84.50 0.016 feet
AVERAGE 0.067 feet
26
For more information on NAVD88, see the FEMA publication entitled
Converting the National Flood Insurance Program to the North American
Vertical Datum of 1988 (FEMA, June 1992), or contact the Vertical Network
Branch, National Geodetic Survey, Coast and Geodetic Survey, National
Oceanic and Atmospheric Administration, Silver Spring, Maryland 20910
(Internet address http://www.ngs.noaa.gov).
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 the FIS report and FIRM
for this community. Interested individuals may contact FEMA to access these
data.
4.0 FLOODPLAIN MANAGEMENT APPLICATIONS
The NFIP encourages State and local governments to adopt sound floodplain
management programs. Therefore, each FIS provides 1-percent-annual-chance flood
elevations and delineations of the 1- and 0.2-percent-annual-chance floodplain
boundaries and 1-percent-annual-chance floodway to assist communities in developing
floodplain management measures. This information is presented on the FIRM and in
many components of the FIS report, including Flood Profiles, Floodway Data Table,
and Summary of Stillwater Elevations Table. Users should reference the data presented
in the FIS report as well as additional information that may be available at the local map
repository before making flood elevation and/or floodplain boundary determinations.
4.1 Floodplain Boundaries
To provide a national standard without regional discrimination, the
1-percent-annual-chance flood has been adopted by FEMA as the base flood for
floodplain management purposes. The 0.2-percent-annual-chance flood is
employed to indicate additional areas of flood risk in the community. For
streams studied by detailed methods, streams restudied by detailed methods, and
redelineated streams, the 1- and 0.2-percent-annual-chance floodplain
boundaries have been delineated using the flood elevations determined at each
cross section. Between cross sections, the boundaries were interpolated using
digital elevation models of the topographic LiDAR data (Photo Science, 2009).
For streams studied by limited detailed or approximate method, the
1-percent-annual-chance floodplain boundaries have been delineated using the
flood elevations determined at each cross section. Between cross sections, the
boundaries were interpolated using digital elevation models of the topographic
LiDAR data (Photo Science, 2009).
27
The 1- and 0.2-percent-annual-chance floodplain boundaries are shown on the
FIRM (Exhibit 2). On this map, the 1-percent-annual-chance floodplain
boundary corresponds to the boundary of the areas of special flood hazards
(Zones A and AE), and the 0.2-percent-annual-chance floodplain boundary
corresponds to the boundary of areas of moderate flood hazards. In cases where
the 1- and 0.2-percent-annual-chance floodplain boundaries are close together,
only the 1-percent-annual-chance 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.
For the streams studied by approximate methods, only the 1-percent-annual-
chance floodplain boundary is shown on the FIRM (Exhibit 2).
4.2 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 1-percent-annual-chance 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 1-percent-annual-chance flood can be carried without substantial
increases in flood heights. Minimum Federal standards limit such increases to 1
foot, provided that hazardous velocities are not produced. The floodways in this
study are presented to local agencies as minimum standards that can be adopted
directly or that can be used as a basis for additional floodway studies.
The floodways presented in this FIS report and on the FIRM were computed for
certain stream segments on the basis of equal-conveyance reduction from each
side of the floodplain. Floodway widths were computed at cross sections.
Between cross sections, the floodway boundaries were interpolated. The results
of the floodway computations have been tabulated for selected cross sections
(Table 6). In cases where the floodway and 1-percent-annual-chance floodplain
boundaries are either close together or collinear, only the floodway boundary has
been shown.
The area between the floodway and 1-percent-annual-chance 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 1-percent-annual-chance flood more than 1
28
foot at any point. Typical relationships between the floodway and the floodway
fringe and their significance to floodplain development are shown in Figure 1.
Figure1 - Floodway Schematic
29
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
CHANDLERS CREEK
A 3,570 200 892 2.7 791.6 791.6 792.6 1.0
B 6,070 57 344 7.0 798.6 798.6 799.6 1.0
C 9,570 224 813 3.0 804.9 804.9 805.6 0.7
D 12,450 284 945 2.5 814.7 814.7 815.4 0.7
E 14,170 577 510 3.5 822.8 822.8 822.8 0.0
F 16,220 348 953 1.9 827.9 827.9 828.8 0.9
G 17,200 205 487 3.7 832.2 832.2 833.0 0.8
H 18,090 170 608 2.9 837.2 837.2 838.1 0.9
I 19,490 202 828 2.2 840.8 840.8 841.8 1.0
J 21,100 74 205 7.2 846.6 846.6 847.0 0.4
1 Feet above confluence with White Oak Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
CHANDLERS CREEK
30
FLOODING SOURCE FLOODWAY
BASE FLOOD
WATER SURFACE ELEVATION
(FEET NAVD)
CROSS SECTION DISTANCE1
WIDTH2
(FEET)
SECTION
AREA
(SQUARE
FEET)
MEAN
VELOCITY
(FEET PER
SECOND)
REGULATORY WITHOUT
FLOODWAY
WITH
FLOODWAY INCREASE
CHATTAHOOCHEE RIVER
AF 47.70 585\0 10,895 6.1 686.7 686.7 687.3 0.6 AG 48.32 778\600 12,954 5.1 688.1 688.1 688.7 0.6 AH 50.00 663\140 11,392 5.8 690.9 690.9 691.5 0.6 AI 52.15 2202\931 25,737 2.6 694.8 694.8 695.4 0.6 AJ 52.94 1,465\583 18,740 3.5 695.8 695.8 696.3 0.5 AK 53.67 1,065\910 13,148 5.1 697.1 697.1 697.6 0.5 AL 54.52 687\201 13,057 4.9 699.2 699.2 699.6 0.4 AM 54.91 501\321 7,908 8.1 699.3 699.3 699.7 0.4 AN 55.55 985\159 12,817 5.0 702.3 702.3 702.7 0.4 AO 56.77 492\314 10,521 6.1 706.3 706.3 706.8 0.5 AP 57.30 646\116 11,688 5.5 707.6 707.6 708.1 0.5 AQ 57.90 665\300 11,372 5.6 709.0 709.0 709.4 0.4 AR 58.08 853\260 15,162 4.2 711.1 711.1 711.7 0.6 AS 58.36 760\345 17,339 3.7 711.7 711.7 712.2 0.5 AT 58.62 901\406 16,606 3.9 712.5 712.5 712.9 0.4 AU 59.45 1,160\746 20,761 3.1 713.9 713.9 714.4 0.5 AV 61.77 1,248\993 20,548 3.0 716.0 716.0 716.6 0.6
1 Miles from West Point Dam
2 Total Width\Width Inside the County
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
CHATTAHOOCHEE RIVER
31
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LAKE AMLAJACK
CREEK
A 1,620 57 257 6.8 835.8 835.8 836.8 1.0
B 4,120 105 351 5.0 844.1 844.1 845.1 1.0
C 5,070 864 7,863 0.2 855.6 855.6 856.6 1.0
D 5,700 1,551 9,573 0.1 855.6 855.6 856.6 1.0
E 6,580 388 461 2.5 856.5 856.5 856.7 0.2
F 8,700 96 150 6.4 870.6 870.6 870.6 0.0
LAKE SUMMERGROVE
BRANCH
A 690 57 252 7.5 797.7 797.7 798.7 1.0
B 8,090 41 247 7.0 827.6 827.6 828.0 0.4
C 9,190 92 377 4.6 831.1 831.1 831.6 0.5
D 10,490 164 449 2.6 835.4 835.4 836.3 0.9
E 11,600 118 260 4.2 839.1 839.1 839.3 0.2
1 Feet above confluence with White Oak Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LAKE AMLAJACK CREEK - LAKE SUMMERGROVE BRANCH
32
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH2
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LINE CREEK
A 66,450 1,320/150 9,640 2.1 749.8 749.8 750.8 1.0
B 68,130 1,560/1,420 14,640 1.4 751.3 751.3 752.3 1.0
C 68,670 1,650/1,350 15,740 1.3 751.6 751.6 752.6 1.0
D 72,250 1,230/800 11,080 1.9 754.4 754.4 755.4 1.0
E 74,050 1,220/1,020 12,120 1.4 755.7 755.7 756.7 1.0
F 77,650 1,780/570 19,010 0.9 757.8 757.8 758.8 1.0
G 79,250 500/260 5,010 3.3 759.1 759.1 759.6 0.5
H 80,770 910/120 7,590 2.2 760.4 760.4 761.3 0.9
I 83,050 370/240 4,680 3.5 763.8 763.8 764.2 0.4
J 84,400 1,410/470 19,530 0.8 764.7 764.7 765.2 0.5
K 87,010 730/240 8,660 1.9 765.1 765.1 765.8 0.7
L 90,940 1,310/1,130 11,790 1.4 766.8 766.8 767.5 0.7
M 91,530 1,340/1,000 12,850 1.3 767.0 767.0 767.6 0.6
N 91,860 590/500 3,970 4.3 767.3 767.3 767.3 0.0
O 93,820 680/200 7,510 2.3 771.8 771.8 772.7 0.9
P 95,100 470/190 7,360 2.3 773.1 773.1 774.1 1.0
Q 104,870 640/310 7,730 1.3 774.2 774.2 775.2 1.0
R 106,220 460/270 6,020 1.7 785.0 785.0 785.0 0.0
S 108,700 620/450 7,190 1.4 785.9 785.9 785.9 0.0
T 110,700 230/130 1,700 6.0 788.5 788.5 788.5 0.0
U 112,260 190/110 1,230 8.3 798.1 798.1 798.1 0.0
1 Feet above mouth 2 Total width/Width within Coweta County
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LINE CREEK
33
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH2
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LINE CREEK
(CONTINUED)
V 115,250 210/150 2,620 3.9 816.0 816.0 816.8 0.8
W 116,770 200/60 2,820 3.6 817.8 817.8 818.8 1.0
X 117,250 450/45 2,220 4.6 818.4 818.4 818.4 0.0
Y 117,720 190/65 1,700 6.0 820.5 820.5 820.5 0.0
Z 118,120 210/135 3,110 3.3 826.9 826.9 827.2 0.3
AA 122,270 1,200/1,000 8,420 1.2 827.2 827.2 827.5 0.3
AB 123,790 1,270/900 9,990 1.0 827.5 827.5 827.9 0.4
AC 125,630 1,060/1,030 9,500 1.1 828.0 828.0 828.8 0.8
AD 128,030 790/500 6,720 1.3 828.9 828.9 829.7 0.8
AE 129,530 560/400 3,910 2.2 830.1 830.1 830.9 0.8
AF 130,930 370/200 3,780 2.2 832.0 832.0 832.8 0.8
AG 132,280 930/150 6,310 1.3 833.3 833.3 834.1 0.8
AH 134,580 280/180 1,990 4.2 836.4 836.4 837.2 0.8
AI 136,580 1,420/910 9,240 0.9 838.7 838.7 839.6 0.9
AJ 139,190 440/180 1,680 4.8 843.0 843.0 843.0 0.0
AK 141,370 200/100 2,240 3.6 850.1 850.1 850.9 0.8
AL 143,970 630/0 6,410 1.3 851.9 851.9 852.7 0.8
AM 145,870 160/100 1,900 4.0 852.7 852.7 853.5 0.8
AN 147,470 320/300 2,550 3.0 855.1 855.1 855.7 0.6
1 Feet above mouth
2 Total width/Width within Coweta County
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LINE CREEK
34
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH2
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LINE CREEK
(CONTINUED)
AO 148,800 390/250 4,170 1.8 856.3 856.3 857.0 0.7
AP 150,730 500/370 2,710 2.8 857.9 857.9 858.6 0.7
AQ 152,160 740/150 5,520 1.3 859.8 859.8 860.6 0.8
AR 154,010 660/230 3,800 1.9 861.2 861.2 862.0 0.8
AS 156,410 380/180 3,080 2.2 864.2 864.2 865.1 0.9
AT 157,870 330/0 2,760 2.5 866.1 866.1 867.0 0.9
AU 159,250 600/410 5,170 1.3 867.4 867.4 868.3 0.9
AV 160,730 280/140 2,610 1.6 868.2 868.2 869.0 0.8
AW 162,830 200/160 1,580 2.4 869.7 869.7 870.5 0.8
AX 165,130 500/410 3,980 1.0 871.1 871.1 871.9 0.8
1 Feet above mouth
2 Total width/Width within Coweta County
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LINE CREEK
35
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LITTLE CREEK
A 2,310 80 560 4.4 830.0 829.82
830.8 1.0
B 3,913 110 510 4.7 834.2 834.2 835.1 0.9
C 5,283 360 1,500 1.6 838.7 838.7 839.7 1.0
D 7,423 150 550 4.2 845.4 845.4 845.9 0.5
E 9,203 310 1,260 1.9 853.2 853.2 853.5 0.3
F 10,743 300 850 2.2 858.2 858.2 858.5 0.3
G 13,050 400 1,030 1.8 868.6 868.6 868.9 0.3
H 15,243 280 320 5.0 879.9 879.9 880.0 0.1
I 16,735 110 240 6.7 888.3 888.3 888.3 0.0
J 19,110 270 350 3.8 904.5 904.5 904.5 0.0
K 20,555 150 280 3.4 912.0 912.0 912.0 0.0
L 22,613 160 210 4.5 928.3 928.3 928.3 0.0
1 Feet above confluence with Line Creek
2 Elevation computed without consideration of backwater effects from Line Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LITTLE CREEK
36
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
LITTLE WAHOO CREEK
A 1,220 153 709 3.2 799.9
799.9 800.6 0.7
B 3,143 358 1,096 2.1 804.4 804.4 805.0 0.6
C 4,594 283 1,050 2.2 808.8 808.8 809.6 0.8
D 6,320 86 364 6.0 814.2 814.2 814.9 0.7
E 8,558 190 692 3.1 821.2 821.2 821.6 0.4
F 10,712 133 526 4.1 828.0 828.0 828.9 0.9
G 11,780 60 291 7.4 832.0 832.0 832.5 0.5
H 12,531 70 408 5.3 835.5 835.5 835.5 0.0
I 13,445 200 881 2.4 838.7 838.7 839.7 1.0
J 14,454 274 800 2.7 841.4 841.4 842.2 0.8
K 16,751 148 467 4.6 851.0 851.0 851.5 0.5
L 17,695 123 586 3.4 855.5 855.5 856.0 0.5
M 18,423 108 537 3.7 859.3 859.3 859.9 0.6
N 19,066 165 546 3.7 863.0 863.0 863.1 0.1
O 20,511 40 265 7.5 869.1 869.1 869.5 0.4
1 Feet above confluence with Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
LITTLE WAHOO CREEK
37
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
MINERAL SPRING
BRANCH
A 60 250 1,010 2.7 753.2 753.2 754.2 1.0
B 950 90 280 9.6 759.5 759.5 759.5 0.0
C 2,100 80 340 8.1 777.3 777.3 777.3 0.0
D 3,480 270 1,580 1.7 783.8 783.8 784.8 1.0
E 4,980 310 540 4.1 788.7 788.7 788.7 0.0
F 6,230 120 610 3.6 795.7 795.7 796.3 0.6
G 6,840 210 900 2.5 797.4 797.4 798.1 0.7
H 7,750 100 400 4.9 800.3 800.3 801.0 0.7
I 8,380 110 500 3.9 804.6 804.6 805.5 0.9
J 9,690 160 720 2.7 810.7 810.7 811.6 0.9
K 10,390 170 430 4.5 813.6 813.6 814.2 0.6
L 11,559 110 350 5.5 824.6 824.6 824.9 0.3
M 13,830 150 290 4.6 837.0 837.0 837.0 0.0
N 15,244 240 420 3.2 852.1 852.1 852.1 0.0
O 16,648 110 180 6.1 865.4 865.4 865.4 0.0
P 17,708 150 210 5.2 879.7 879.7 879.7 0.0
Q 18,381 70 200 5.6 885.2 885.2 885.2 0.0
R 18,861 70 100 11.2 889.3 889.3 889.3 0.0
S 19,629 70 80 6.5 894.2 894.2 894.2 0.0
T 21,014 70 45 7.7 909.9 909.9 909.9 0.0
1 Feet above confluence with Mountain Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
MINERAL SPRING BRANCH
38
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
PARADISE LAKES
BRANCH
A 1,7901 123 483 5.1 788.1 785.0
2 786.0 1.0
B 3,4501 111 543 4.6 791.2 791.2 792.2 1.0
C 5,5701 76 245 8.9 795.9 795.9 795.9 0.0
D 7,3901 191 490 4.5 803.5 803.5 803.5 0.0
E 9,4901 41 251 8.6 808.9 808.9 809.6 0.7
PEEKS CREEK
A 1,7503 120 750 5.0 868.9 868.9 869.8 0.9
B 4,4303 200 1,480 2.5 877.5 877.5 878.5 1.0
C 5,7803 550 3,850 1.0 879.3 879.3 880.3 1.0
D 7,3403 480 1,980 1.6 880.2 880.2 881.1 0.9
E 9,8703 240 1,320 2.3 885.6 885.6 886.5 0.9
F 11,8603 260 980 3.1 892.2 892.2 893.1 0.9
1 Feet above confluence with White Oak Creek
2 Elevation computed without consideration of backwater effects from White Oak Creek
3 Feet above confluence with Line Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
PARADISE LAKES BRANCH-PEEKS CREEK
39
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
PERSIMMON CREEK
A 1,100 180 930 2.4 865.8 865.8 866.8 1.0
B 2,550 4302 1,960 1.1 867.3 867.3 868.3 1.0
C 4,150 170 480 4.6 869.4 869.4 869.9 0.5
D 5,650 220 900 2.2 876.9 876.9 877.5 0.6
E 7,150 160 430 4.6 885.6 885.6 885.6 0.0
F 8,650 210 1,430 1.0 893.8 893.8 894.4 0.6
G 9,260 290 2,020 0.7 896.8 896.8 897.5 0.7
1 Feet above confluence with Line Creek
2 Includes combined floodway width with Tributary 1 to Persimmon Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
PERSIMMON CREEK
40
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
SANDY CREEK
A 18,370 210 1,260 3.7 712.4 712.4 713.2 0.8
B 18,870 200 1,210 3.8 713.7 713.7 714.6 0.9
C 19,450 400 1,630 2.8 715.9 715.9 716.8 0.9
D 19,930 460 2,130 2.2 717.7 717.7 718.5 0.8
E 21,290 130 770 5.7 721.2 721.2 722.0 0.8
F 21,850 280 1,660 2.6 723.3 723.3 724.3 1.0
G 22,540 280 1,680 2.6 724.7 724.7 725.7 1.0
H 23,230 640 3,630 0.8 725.4 725.4 726.4 1.0
I 24,100 240 1,020 3.0 725.9 725.9 726.8 0.9
J 32,930 320 640 4.2 752.5 752.5 752.5 0.0
K 34,070 210 750 3.3 760.4 760.4 760.4 0.0
L 34,780 210 1,020 2.4 762.9 762.9 763.3 0.4
M 35,540 240 640 3.9 765.0 765.0 766.0 1.0
N 35,990 120 580 4.3 767.8 767.8 768.5 0.7
O 36,300 290 1,490 1.7 769.6 769.6 770.1 0.5
P 37,800 200 1,260 1.9 771.9 771.9 772.9 1.0
Q 37,920 144 510 4.4 772.6 772.6 773.4 0.8
R 39,540 170 690 3.2 781.2 781.2 781.2 0.0
S 40,900 160 1,160 1.9 783.7 783.7 784.1 0.4
T 43,130 80 50 8.2 791.5 791.5 791.5 0.0
1 Feet above confluence with Mountain Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
SANDY CREEK
41
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
SANDY CREEK
(CONTINUED)
U 45,560 160 660 2.7 807.1 807.1 807.1 0.0
V 47,390 160 370 4.2 814.6 814.6 814.6 0.0
W 48,590 20 70 10.8 821.0 821.0 821.0 0.0
X 49,590 60 150 4.9 834.2 834.2 834.2 0.0
Y 50,250 40 120 6.4 841.7 841.7 841.7 0.0
Z 51,050 70 120 6.5 858.6 858.6 858.6 0.0
AA 52,070 20 70 7.6 867.4 867.4 867.4 0.0
AB 53,030 100 140 3.7 885.9 885.9 885.9 0.0
AC 53,580 110 140 1.9 896.8 896.8 896.8 0.0
AD 54,040 20 50 5.7 901.1 901.1 901.1 0.0
1 Feet above confluence with Mountain Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
SANDY CREEK
42
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
SHOAL CREEK
A 3,650 310 1,980 3.7 774.5 774.5 775.3 0.8
B 4,790 320 2,320 3.1 778.5 778.5 779.4 0.9
C 6,130 660 4,070 1.8 781.3 781.3 782.2 0.9
D 8,830 260 2,100 3.4 785.5 785.5 786.3 0.8
E 10,230 230 1,750 4.0 788.8 788.8 789.6 0.8
F 11,900 170 1,900 3.6 792.2 792.2 793.1 0.9
G 13,460 250 2,170 3.2 794.5 794.5 795.3 0.8
H 15,400 220 2,000 3.5 797.4 797.4 798.2 0.8
I 17,300 1,110 8,020 0.7 798.1 798.1 798.9 0.8
J 18,260 380 2,370 2.5 798.1 798.1 798.9 0.8
K 19,900 210 750 7.7 800.0 800.0 800.0 0.0
L 22,330 940 4,970 1.2 806.2 806.2 806.5 0.3
M 23,600 150 530 10.9 807.8 807.8 807.8 0.0
N 26,300 440 2,730 2.0 817.9 817.9 818.4 0.5
O 28,970 360 2,140 2.5 822.2 822.2 823.1 0.9
P 31,130 380 1,830 2.7 828.3 828.3 829.2 0.9
Q 33,630 410 2,230 2.2 835.1 835.1 836.0 0.9
R 35,900 380 3,050 1.5 837.9 837.9 838.7 0.8
S 38,400 340 1,100 3.4 841.5 841.5 842.2 0.7
T 39,830 410 2,070 1.8 847.3 847.3 848.2 0.9
U 41,200 100 410 8.3 852.7 852.7 852.7 0.0
1 Feet above confluence with Line Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
SHOAL CREEK
43
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
SHOAL CREEK
(CONTINUED)
V 43,790 210 1,410 2.1 862.9 862.9 863.5 0.6
W 45,440 250 1,020 2.5 865.4 865.4 866.2 0.8
X 47,080 290 1,230 1.8 867.7 867.7 868.6 0.9
Y 49,000 250 500 4.3 875.1 875.1 875.1 0.0
Z 51,000 330 1,490 1.3 881.0 881.0 881.6 0.6
1 Feet above confluence with Line Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
SHOAL CREEK
44
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
SNAKE CREEK
A 2,014 257 719 3.2 799.2
798.32
799.1 0.8
B 3,645 360 1,047 2.2 804.4 804.4 805.3 0.9
C 5,764 252 809 2.8 814.6 814.6 814.6 0.0
D 9,469 184 531 4.4 829.4 829.4 830.0 0.6
E 12,276 49 298 7.8 843.1 843.1 843.6 0.5
F 12,477 85 818 2.8 848.1 848.1 848.6 0.5
G 13,855 58 277 7.0 851.9 851.9 851.9 0.0
H 14,132 135 1,240 2.2 863.7 863.7 863.7 0.0
I 15,022 205 1,214 2.3 864.1 864.1 864.1 0.0
J 15,595 169 1,445 2.0 869.1 869.1 869.1 0.0
K 16,430 129 994 2.8 875.2 875.2 875.5 0.3
L 17,383 117 617 2.8 880.5 880.5 881.0 0.5
M 18,110 176 971 1.8 891.5 891.5 891.6 0.1
N 18,462 107 369 2.7 891.5 891.5 891.6 0.1
O 18,979 68 172 5.7 898.1 898.1 898.2 0.1
P 19,314 71 263 3.7 902.8
902.8
902.8 0.0
Q 19,462 105 401 2.5 907.4 907.4 908.0 0.6
R 20,089 27 104 9.4 909.2 909.2 909.3 0.1
S 20,522 104 177 5.5 917.3 917.3 917.3 0.0
T 21,157 20 87 11.2 927.1 927.1 927.1 0.0
1 Feet above confluence with Wahoo Creek
2 Elevation computed without consideration of backwater effects from Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
SNAKE CREEK
45
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO LINE
CREEK
A 7001 1,300
2 450 4.0 773.4 764.2
3 765.2 1.0
B 2,4701 150 600 3.0 773.4 771.0
4 772.0 1.0
C 3,8501 220 920 1.8 775.5 775.5 776.5 1.0
D 5,9801 110 340 4.2 784.4 784.4 785.1 0.7
E 7,3001 130 490 2.9 789.7 789.7 790.5 0.8
TRIBUTARY 1 TO
MINERAL SPRING
BRANCH
A 5005 370 290 4.0 785.1 785.1 785.1 0.0
B 2,0805 250 270 3.2 797.0 797.0 797.0 0.0
C 3,7505 100 90 9.4 810.5 810.5 810.5 0.0
D 4,4505 90 120 6.8 821.9 821.9 821.9 0.0
E 6,8705 70 80 5.6 857.5 857.5 857.5 0.0
F 8,9305 60 60 7.6 893.3 893.3 893.3 0.0
1 Feet above confluence with Line Creek
5 Feet above confluence with Mineral Spring Branch
2 Includes combined floodway width with Line Creek
3 Elevation computed without consideration of flooding controlled by Line Creek
4 Elevation computed without consideration of backwater effects from Line Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO LINE CREEK-
TRIBUTARY 1 TO MINERAL SPRING BRANCH
46
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO
PERSIMMON CREEK
A 8651 430
2 180 3.4 867.3 864.0
3 865.0
1.0
B 3,0601 130 170 3.7 890.4 890.4 890.4 0.0
C 5,3901 110 180 3.4 912.7 912.7 912.7 0.0
TRIBUTARY 1 TO
SANDY CREEK
A 504 240 510 2.1 718.3 715.6
5 716.6 1.0
B 1,5804 150 530 2.0 724.4 724.4 725.4 1.0
C 2,8004 110 240 4.0 733.4 733.4 733.7 0.3
1 Feet above confluence with Persimmon Creek
2 Includes combined floodway width with Persimmon Creek
3 Elevation computed without consideration of flooding controlled by Persimmon Creek
4 Feet above confluence with Sandy Creek
5 Elevation computed without consideration of backwater effects from Sandy Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO PERSIMMON CREEK-
TRIBUTARY 1 TO SANDY CREEK
47
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO
SHOAL CREEK
A 1001 400 1,210 2.6 797.8 791.8
2 792.8
1.0
B 2,3301 120 740 4.1 799.9 799.9 800.9 1.0
1 Feet above confluence with Shoal Creek
2 Elevation computed without consideration of backwater effects from Shoal Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO SHOAL CREEK
48
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO
SNAKE CREEK
A 2651
31 36 5.3 875.3
873.22
873.2 0.0
B 5311
25 91 2.1 880.5 880.5 880.5 0.0
C 9341
21 37 5.2 888.5 888.5 889.0 0.5
D 1,2971
24 63 3.0 893.1 893.1 893.8 0.7
TRIBUTARY 1 TO
TURKEY CREEK
A 1,5403 37 277 4.6 876.3 876.3 877.3 1.0
B 1,6403 663 5,403 0.2 896.5 896.5 896.5 0.0
C 4,3203 330 2,033 0.6 896.5 896.5 896.5 0.0
1 Feet above confluence with Snake Creek
2 Elevation computed without consideration of backwater effects from Snake Creek
3 Feet above confluence with Turkey Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO SNAKE CREEK-
TRIBUTARY 1 TO TURKEY CREEK
49
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO
WAHOO CREEK
A 386 36 79 6.7 842.1 838.52
838.7 0.2
B 708 87 387 1.4 843.1 843.1 843.5 0.4
C 1,090 248 940 0.9 857.9 857.9 857.9 0.0
D 2,064 204 238 3.4 858.2 858.2 858.2 0.0
E 3,434 30 129 6.2 872.0 872.0 872.4 0.4
F 3,902 241 1,780 0.5 889.3 889.3 889.3 0.0
G 4,239 90 222 2.6 889.4 889.4 889.4 0.0
H 5,065 15 68 8.4 907.2 907.2 907.3 0.1
I 5,427 28 171 3.3 917.4 917.4 918.4 1.0
J 5,943 19 58 10.1 941.0 941.0 941.5 0.5
1
Feet above confluence with Wahoo Creek
2 Elevation computed without consideration of backwater effects from Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO WAHOO CREEK
50
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 1 TO
WHITE OAK CREEK
A 1,300 94 366 5.2 804.1 804.1 805.1 1.0
B 2,410 79 285 6.7 808.4 808.4 809.3 0.9
C 3,210 131 366 5.2 811.2 811.2 812.2 1.0
D 4,030 77 231 8.2 814.8 814.8 815.5 0.7
E 5,110 95 362 5.2 820.5 820.5 821.4 0.9
F 6,110 196 795 2.4 823.8 823.8 824.5 0.7
G 7,030 72 236 8.1 831.5 831.5 831.5 0.0
H 8,920 27 159 6.6 842.8 842.8 843.1 0.3
1 Feet above confluence with White Oak Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 1 TO WHITE OAK CREEK
51
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 2 TO
MINERAL SPRING
BRANCH
A 210 280 370 2.7 830.2 825.32
825.3
0.0
B 2,180 100 180 5.6 836.4 836.4 836.4 0.0
C 3,630 60 100 7.7 847.9 847.9 847.9 0.0
D 4,430 50 120 6.3 856.0 856.0 856.0 0.0
E 5,100 80 80 9.8 866.8 866.8 866.8 0.0
F 5,920 70 35 7.6 879.0 879.0 879.0 0.0
G 6,320 70 45 5.8 887.7 887.7 887.7 0.0
H 6,690 70 30 8.2 895.9 895.9 895.9 0.0
I 7,300 70 30 8.0 916.3 916.3 916.3 0.0
1 Feet above confluence with Mineral Spring Branch
2 Elevation computed without consideration of backwater effects from Mineral Spring Branch
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 2 TO MINERAL SPRING BRANCH
52
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 2 TO
SANDY CREEK
A 2501 120 200 5.2 795.3 795.3 795.3 0.0
B 2,4501 60 100 3.6 813.2 813.2 813.2 0.0
C 4,3101 20 50 7.9 855.9 855.9 855.9 0.0
TRIBUTARY 2 TO
SHOAL CREEK
A 7002 370 1,260 2.0 838.7 834.6
3 835.5
0.9
B 2,9202 170 660 3.5 843.2 843.2 844.1 0.9
C 4,7002 140 660 3.5 848.6 848.6 849.6 1.0
D 6,2002 170 420 4.5 853.4 853.4 854.1 0.7
E 8,2202 270 400 4.7 860.3 860.3 860.4 0.1
1 Feet above confluence with Tributary 3 to Sandy Creek 2 Feet above confluence with Shoal Creek
3 Elevation computed without consideration of backwater effects from Shoal Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 2 TO SANDY CREEK-
TRIBUTARY 2 TO SHOAL CREEK
53
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 2 TO
SNAKE CREEK
A 315
16 55 11.0 891.5 890.42
890.4 0.0
B 574
20 93 6.4 897.6 897.6 898.3 0.7
C 864
27 270 2.2 908.6 908.6 909.0 0.4
D 1,224
71 370 1.6 918.1 918.1 918.1 0.0
E 1,395
37 274 2.2 918.2 918.2 918.2 0.0
F 1,877
12 53 11.4 927.5 927.5 927.6 0.1
1 Feet above confluence with Snake Creek
2 Elevation computed without consideration of backwater effects from Snake Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 2 TO SNAKE CREEK
54
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 2 TO
WAHOO CREEK
A 982 144 274 4.0 861.3 861.3 861.3 0.0
B 1,553 39 231 4.8 864.2 864.2 864.5 0.3
C 2,142 60 330 3.3 867.9 867.9 868.1 0.2
D 2,847 60 229 2.4 868.4 868.4 869.3 0.9
E 3,151 267 682 1.7 871.3 871.3 871.4 0.1
F 3,850 34 118 5.6 872.4 872.4 872.4 0.0
G 4,059 31 120 5.5 876.5 876.5 876.5 0.0
H 4,756 32 156 3.5 880.8 880.8 881.4 0.6
I 4,996 38 337 1.6 891.8 891.8 891.8 0.0
J 5,472 41 428 1.3 899.9 899.9 899.9 0.0
K 6,168 61 219 2.5 903.7 903.7 903.8 0.1
L 6,334 59 456 1.2 908.7 908.7 909.5 0.8
M 6,690 40 151 3.7 909.5 909.5 910.4 0.9
N 7,377 31 103 5.4 920.4 920.4 921.0 0.6
1 Feet above confluence with Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 2 TO WAHOO CREEK
55
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 3 TO
SANDY CREEK
A 6,600 260 880 3.1 740.0 740.0 740.7 0.7
B 8,300 160 940 2.9 744.7 744.7 745.5 0.8
C 9,700 460 770 3.5 748.8 748.8 749.1 0.3
D 12,000 260 630 4.3 758.1 758.1 758.1 0.0
E 14,400 460 870 2.8 766.0 766.0 766.1 0.1
F 16,100 290 580 4.1 777.9 777.9 777.9 0.0
G 17,640 310 1,350 1.8 784.3 784.3 784.7 0.4
H 19,900 100 470 4.5 790.6 790.6 790.9 0.3
I 22,500 210 310 5.7 804.6 804.6 804.6 0.0
J 27,680 160 490 2.1 832.4 832.4 832.4 0.0
K 29,180 70 170 6.2 836.1 836.1 836.1 0.0
L 30,630 180 360 2.8 848.0 848.0 848.0 0.0
1 Feet above confluence with Sandy Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 3 TO SANDY CREEK
56
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 3 TO
SHOAL CREEK
A 4751 220 420 2.2 854.0 853.4
2 853.4 0.0
B 2,2951 170 484 1.9 859.9 859.9 859.9 0.0
C 3,3151 200 240 3.9 871.0 871.0 871.0 0.0
D 5,0151 220 350 1.3 883.8 883.8 883.8 0.0
E 6,7451 25 50 8.5 896.4 896.4 896.4 0.0
TRIBUTARY 3 TO
WAHOO CREEK
A 2273
71 430 0.5 868.2 868.2 868.4 0.2
B 5303
176 833 0.8 870.6 870.6 870.9 0.3
C 1,2923
61 118 1.6 870.9 870.9 871.0 0.1
D 1,5463
70 50 3.7 876.2 876.2 876.2 0.0
E 2,0723
48 191 1.0 885.4 885.4 885.4 0.0
1 Feet above confluence with Shoal Creek
2 Elevation computed without consideration of backwater effects from Shoal Creek
3 Feet above confluence with Tributary 2 to Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 3 TO SHOAL CREEK-
TRIBUTARY 3 TO WAHOO CREEK
57
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 4 TO
WAHOO CREEK
A 3001
96 147 1.5 871.0 871.0 871.0 0.0
B 6841
41 51 4.3 873.2 873.2 873.2 0.0
C 7711
25 38 5.7 876.7 876.7 876.9 0.2
D 9671
203 829 0.3 884.7 884.7 884.7 0.0
TRIBUTARY 5 TO
WAHOO CREEK
A 2802
22 37 1.7 879.1 879.1 879.4 0.3
B 5792
16 12 5.0 887.9 887.9 888.0 0.1
TRIBUTARY 6 TO
WAHOO CREEK
A 2442
7 13 5.1 881.4 881.4 882.0 0.6
B 5922
132 862 0.1 896.7 896.7 896.7 0.0
1 Feet above confluence with Tributary 3 to Wahoo Creek
2 Feet above confluence with Tributary 2 to Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 4 TO WAHOO CREEK –
TRIBUTARY 5 TO WAHOO CREEK –
TRIBUTARY 6 TO WAHOO CREEK
58
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 7 TO
WAHOO CREEK
A 464 27 112 9.7 859.7 855.62
856.0 0.4
B 647 123 1,159 0.9 864.5 864.5 865.3 0.8
C 1,540 63 330 3.3 865.1 865.1 865.7 0.6
D 1,718 245 1,180 0.9 881.2 881.2 881.2 0.0
E 2,392 58 143 7.6 881.7 881.7 881.7 0.0
F 2,453 75 161 6.2 887.0 887.0 887.0 0.0
G 2,973 27 97 10.3 890.7 890.7 890.7 0.0
H 3,426 30 106 9.3 898.3 898.3 898.5 0.2
TRIBUTARY 8 TO
WAHOO CREEK
A 668 50 117 4.3 865.6 865.6 865.8 0.2
B 1,132 23 121 4.1 870.1 870.1 870.2 0.1
C 1,785 30 70 7.1 891.4 891.4 892.1 0.7
D 2,160 22 127 3.9 898.6 898.6 899.3 0.7
TRIBUTARY 9 TO
WAHOO CREEK
A 672 29 60 6.3 875.7 875.7 875.7 0.0
B 1,334 50 71 5.4 883.0 883.0 883.2 0.2
C 1,815 42 59 6.5 904.7 904.7 905.1 0.4
1 Feet above confluence with Wahoo Creek
2 Elevation computed without consideration of backwater effects from Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 7 TO WAHOO CREEK-
TRIBUTARY 8 TO WAHOO CREEK
TRIBUTARY 9 TO WAHOO CREEK
59
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 10 TO
WAHOO CREEK
A 302 29 49 5.5 883.1 883.1 883.2 0.1
B 1,106 119 90 3.0 896.5 896.5 896.5 0.0
C 2,326 21 50 5.3 914.9 914.9 915.2 0.3
D 3,321 19 42 6.3 934.3 934.3 934.6 0.3
TRIBUTARY 11 TO
WAHOO CREEK
A 343 229 559 2.1 881.1 881.1 881.1 0.0
B 719 69 163 7.2 882.6 882.6 882.8 0.2
C 986 75 247 4.8 888.3 888.3 888.3 0.0
D 1,240 70 410 2.9 894.0 894.0 894.6 0.6
E 1,676 58 252 4.7 894.6 894.6 895.3 0.7
F 2,601 59 257 4.6 905.9 905.9 906.1 0.2
1 Feet above confluence with Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 10 TO WAHOO CREEK-
TRIBUTARY 11 TO WAHOO CREEK
60
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TRIBUTARY 12 TO
WAHOO CREEK
A 507 58 128 6.5 898.0 898.0 898.2 0.2
B 1,017 30 89 9.4 903.9 903.9 903.9 0.0
C 1,712 21 77 10.9 911.9 911.9 911.9 0.0
D 1,934 91 196 4.3 918.3 918.3 918.8 0.5
E 2,502 33 126 6.6 924.6 924.6 925.0 0.4
F 3,000 48 167 5.0 935.4 935.4 935.4 0.0
G 3,215 19 187 4.5 940.3 940.3 941.2 0.9
H 3,634 33 122 6.8 944.1 944.1 944.9 0.8
1 Feet above confluence with Wahoo Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TRIBUTARY 12 TO WAHOO CREEK
61
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
TURKEY CREEK
A 2,700 67 339 9.2 791.1 790.32 791.1 0.8
B 4,510 107 371 8.4 797.0 797.0 797.1 0.1
C 7,930 145 499 6.3 805.9 805.9 806.2 0.3
D 8,005 103 314 10.0 813.2 813.2 813.2 0.0
E 8,030 965 3,310 0.9 814.9 814.9 814.9 0.0
F 10,400 112 319 6.8 816.2 816.2 816.3 0.1
G 11,720 216 739 3.0 820.9 820.9 821.5 0.6
H 14,400 70 330 6.1 831.1 831.1 831.1 0.0
I 16,730 34 191 10.5 847.0 847.0 847.1 0.1
J 18,640 71 225 8.9 863.8 863.8 863.8 0.0
K 20,550 383 1,567 0.9 870.1 870.1 871.1 1.0
L 21,230 153 493 2.8 870.3 870.3 871.3 1.0
M 22,210 129 300 4.7 872.9 872.9 873.2 0.3
N 22,290 89 206 6.8 874.3 874.3 874.3 0.0
O 23,370 28 128 11.0 882.5 882.5 882.5 0.0
P 24,490 63 203 6.9 889.5 889.5 889.5 0.0
1 Feet above confluence with White Oak Creek
2 Elevation computed without consideration of backwater effects from White Oak Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
TURKEY CREEK
62
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
WAHOO CREEK
A 2,698 766 7,178 1.3 700.6 698.32
698.3 0.0
B 3,641 343 2,697 3.4 700.6 698.32
698.3 0.0
C 6,823 165 1,468 6.2 702.1 702.1 702.9 0.8
D 8,904 122 1,128 8.0 715.0 715.0 715.3 0.3
E 10,680 133 1,568 5.8 719.5 719.5 720.0 0.5
F 13,544 156 1,850 4.8 722.6 722.6 723.0 0.4
G 15,103 277 3,916 2.3 725.9 725.9 726.5 0.6
H 17,548 1,012 11,747 0.8 726.9 726.9 727.6 0.7
I 19,148 510 4,513 2.0 727.0 727.0 727.7 0.7
J 19,558 573 4,887 1.8 727.2 727.2 727.9 0.7
K 21,753 988 6,376 1.4 729.0 729.0 729.8 0.8
L 22,893 697 4,837 1.8 731.6 731.6 732.2 0.6
M 24,791 551 3,153 2.8 733.0 733.0 733.5 0.5
N 27,109 187 1,050 8.4 736.1 736.1 736.5 0.4
O 27,918 130 935 9.4 739.9 739.9 740.1 0.2
P 28,169 166 1,111 7.9 749.9 749.9 749.9 0.0
Q 29,294 114 641 12.6 753.5 753.5 753.5 0.0
R 29,358 122 1,246 6.5 760.1 760.1 760.6 0.5
S 30,321 268 2,081 3.9 777.5 777.5 777.6 0.1
T 31,693 290 1,980 4.1 779.5 779.5 779.5 0.0
U 33,263 1,104 6,753 1.4 783.6 783.6 784.2 0.6
1 Feet above confluence with Chattahoochee River
2 Elevation computed without consideration of backwater effects from Chattahoochee River
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
WAHOO CREEK
63
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
WAHOO CREEK
(CONTINUED)
V 35,956 474 1,921 4.9 784.4 784.4 784.8 0.4
W 38,983 170 1,037 9.1 790.8 790.8 790.8 0.0
X 40,335 358 3,707 2.5 797.2 797.2 797.7 0.5
Y 41,917 5122
5,121 1.8 798.9 798.9 799.9 1.0
Z 44,685 432 2,022 2.3 799.7 799.7 800.6 0.9
AA 47,848 211 1,641 2.8 810.2 810.2 811.0 0.8
AB 49,980 419 2,418 1.9 812.4 812.4 813.1 0.7
AC 51,440 453 3,425 1.3 816.7 816.7 816.9 0.2
AD 54,418 422 1,061 4.0 820.6 820.6 820.9 0.3
AE 55,565 226 1,356 2.7 825.6 825.6 826.3 0.7
AF 56,195 530 4,461 0.8 831.7 831.7 831.9 0.2
AG 58,077 246 809 4.5 832.2 832.2 832.6 0.4
AH 59,614 301 1,944 1.9 839.3 839.3 839.8 0.5
AI 60,104 358 1,980 1.8 839.4 839.4 840.0 0.6
AJ 61,306 314 2,096 1.4 842.2 842.2 842.6 0.4
AK 63,427 128 806 2.3 848.6 848.6 849.0 0.4
AL 64,567 210 856 2.1 849.1 849.1 849.8 0.7
AM 65,415 698 6,892 0.7 859.3 859.3 860.0 0.7
AN 67,855 85 508 3.5 859.8 859.8 860.3 0.5
AO 68,970 312 2,135 1.4 867.1 867.1 867.1 0.0
1 Feet above confluence with Chattahoochee River
2 Includes combined floodway width with Snake Creek
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
WAHOO CREEK
64
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1 WIDTH
(FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
WAHOO CREEK
(CONTINUED)
AP 71,697 240 738 4.0 871.9 871.9 872.4 0.5
AQ 72,975 257 1,113 2.8 880.4 880.4 880.4 0.0
AR 73,865 243 448 2.6 881.6 881.6 881.6 0.0
AS 74,825 29 135 8.5 887.3 887.3 887.8 0.5
AT 75,603 235 650 0.9 896.6 896.6 896.7 0.1
AU 76,612 19 67 8.6 905.5 905.5 906.1 0.6
AV 77,421 19 92 6.3 919.4 919.4 919.6 0.2
AW 77,898 47 574 1.0 935.4 935.4 936.3 0.9
AX 78,241 19 116 5.0 935.4 935.4 936.1 0.7
AY 78,808 14 53 11.0 944.7 944.7 944.7 0.0
1 Feet above confluence with Chattahoochee River
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
WAHOO CREEK
65
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
WHITE OAK CREEK
A 36,400 391 4,059 3.4 772.5 772.5 773.5 1.0
B 38,740 220 2,899 4.3 775.2 775.2 776.0 0.8
C 41,650 1,136 15,143 0.8 776.6 776.6 777.4 0.8
D 42,500 419 5,418 2.3 776.6 776.6 777.4 0.8
E 44,900 574 6,699 1.6 777.6 777.6 778.4 0.8
F 46,780 389 4,325 2.5 779.4 779.4 780.0 0.6
G 49,090 898 9,445 1.1 780.5 780.5 781.1 0.6
H 51,600 681 5,170 2.1 780.9 780.9 781.9 1.0
I 54,380 393 3,959 2.7 783.8 783.8 784.3 0.5
J 57,650 286 2,988 3.2 787.6 787.6 788.3 0.7
K 60,380 1,150 7,799 1.0 788.8 788.8 789.7 0.9
L 63,160 920 5,139 1.5 790.6 790.6 791.1 0.5
M 66,010 610 3,042 2.1 792.2 792.2 793.0 0.8
N 68,240 700 2,287 2.7 797.4 797.4 797.4 0.0
O 68,760 405 1,912 2.9 797.5 797.5 797.6 0.1
P 70,560 320 870 6.3 799.5 799.5 799.7 0.2
Q 71,660 467 1,922 2.8 801.6 801.6 802.5 0.9
R 74,260 468 1,210 4.5 807.2 807.2 807.7 0.5
S 76,360 400 1,381 3.1 813.4 813.4 813.9 0.5
T 77,840 539 2,897 1.3 816.7 816.7 816.8 0.1
U 78,840 217 703 5.5 817.1 817.1 817.2 0.1
1 Feet above county boundary
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
WHITE OAK CREEK
66
FLOODING SOURCE FLOODWAY 1-PERCENT-ANNUAL-CHANCE-FLOOD
WATER SURFACE ELEVATION
CROSS SECTION DISTANCE1
WIDTH (FEET)
SECTION AREA
(SQUARE FEET)
MEAN VELOCITY (FEET PER SECOND)
REGULATORY (FEET NAVD)
WITHOUT FLOODWAY (FEET NAVD)
WITH FLOODWAY (FEET NAVD)
INCREASE (FEET)
WHITE OAK CREEK
(CONTINUED)
V 80,930 369 1,628 2.4 823.3 823.3 824.3 1.0
W 82,950 103 608 5.5 826.5 826.5 827.1 0.6
X 85,190 150 538 6.2 831.5 831.5 832.1 0.6
Y 86,000 300 1,341 2.5 833.2 833.2 833.7 0.5
Z 87,240 400 3,054 0.6 837.8 837.8 837.8 0.0
AA 88,140 500 1,329 1.3 837.8 837.8 837.8 0.0
AB 89,730 197 432 4.1 841.0 841.0 841.0 0.0
AC 91,200 309 850 2.1 846.7 846.7 847.0 0.3
AD 93,100 155 501 2.3 853.2 853.2 853.5 0.3
AE 94,400 222 303 3.8 861.0 861.0 861.1 0.1
AF 97,000 336 436 1.8 872.0 872.0 872.1 0.1
AG 98,550 72 151 5.2 881.9 881.9 882.6 0.7
1 Feet above county boundary
TA
BL
E 6
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA
AND INCORPORATED AREAS
FLOODWAY DATA
WHITE OAK CREEK
67
5.0 INSURANCE APPLICATIONS
For flood insurance rating purposes, flood insurance zone designations are assigned to a
community based on the results of the engineering analyses. These zones are as follows:
Zone A
Zone A is the flood insurance risk zone that corresponds to the 1-percent-annual-chance
floodplains that are determined in the FIS by approximate methods. Because detailed
hydraulic analyses are not performed for such areas, no BFEs or base flood depths are
shown within this zone.
Zone AE
Zone AE is the flood insurance risk zone that corresponds to the 1-percent-annual-chance
floodplains that are determined in the FIS by detailed methods. In most instances, whole-
foot BFEs derived from the detailed hydraulic analyses are shown at selected intervals
within this zone.
Zone X
Zone X is the flood insurance risk zone that corresponds to areas outside the 0.2-
percent-annual-chance floodplain, areas within the 0.2-percent-annual-chance floodplain,
areas of 1-percent-annual-chance flooding where average depths are less than 1 foot,
areas of 1-percent-annual-chance flooding where the contributing drainage area is less
than 1 square mile, and areas protected from the 1-percent-annual-chance flood by levees.
No BFEs or base flood depths are shown within this zone.
6.0 FLOOD INSURANCE RATE MAP
The FIRM is designed for flood insurance and floodplain management applications.
For flood insurance applications, the map designates flood insurance risk zones as
described in Section 5.0 and, in the 1-percent-annual-chance floodplains that were
studied by detailed methods, shows selected whole-foot BFEs or average depths.
Insurance agents use the zones and BFEs 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 1- and 0.2-percent-annual-chance floodplains, floodways, and the locations of
selected cross sections used in the hydraulic analyses and floodway computations.
This countywide FIRM presents flooding information for the entire geographic area of
Coweta County. Previously, FIRMs were prepared for each incorporated community and
68
the unincorporated areas of the county identified as flood-prone. This countywide FIRM
also includes flood-hazard information that was presented separately on Flood Boundary
and Floodway Maps, where applicable. Historical data relating to the maps prepared for
each community are presented in Table 7, “Community Map History.”
7.0 OTHER STUDIES
This report either supersedes or is compatible with all previous studies on streams studied
in this report and should be considered authoritative for purposes of the NFIP.
8.0 LOCATION OF DATA
Information concerning the pertinent data used in the preparation of this study can be
obtained by contacting FEMA, Federal Insurance and Mitigation Division, Federal
Regional Center, 3003 Chamblee-Tucker Road, Atlanta, Georgia 30341.
9.0 BIBLIOGRAPHY AND REFERENCES
1. 2010 U.S. Census: Coweta County, Georgia. Retrieved on April 19, 2011,
from http://factfinder2.census.gov
2. Dewberry and Davis LLC, Georgia Department of Natural Resources
Cooperating Technical Partner Mapping Activity Statement No. FY09.09,
FEMA Contract Number: EMA-2009-CA-5930, Chattahoochee River
Hydrologic Study: Buford Dam to West Point Lake, April 2011.
3. Dewberry and Davis LLC, Georgia Department of Natural Resources
Cooperating Technical Partner Mapping Activity Statement No. FY09.09,
FEMA Contract Number: EMA-2009-CA-5930, Chattahoochee River
Hydraulic Study, May 2011.
4. Dewberry and Davis LLC, Georgia Department of Natural Resources
Cooperating Technical Partner Mapping Activity Statement No. FY09.09,
FEMA Contract Number: EMA-2009-CA-5930, Coweta County, GA:
Hydrology Report, October 2010.
5. Dewberry and Davis LLC, Georgia Department of Natural Resources
Cooperating Technical Partner Mapping Activity Statement No. FY09.09,
FEMA Contract Number: EMA-2009-CA-5930, Coweta County, GA:
Hydraulic Report, October 2010.
69
COMMUNITY NAME
INITIAL IDENTIFICATION
FLOOD HAZARD BOUNDARY MAP REVISION DATE
FIRM EFFECTIVE DATE
FIRM REVISION DATE
Coweta County (Unincorporated Areas)
April 30, 1976 None August 2, 1982 September 8, 1999
Grantville, City of May 16, 2006 None May 16, 2006 None
Haralson, Town of May 16, 2006 None May 16, 2006 None
Moreland, Town of April 18, 1975 None September 27, 1985 None
Newnan, City of May 31, 1974 February 6, 1976 November 15, 1978 None
Senoia, City of April 4, 1975 None July 1, 1987 None
Sharpsburg, Town of N/A N/A N/A N/A
Turin, Town of May 16, 2006 None May 16, 2006 None
TA
BL
E 7
FEDERAL EMERGENCY MANAGEMENT AGENCY
COWETA COUNTY, GA AND INCORPORATED AREAS
COMMUNITY MAP HISTORY
Table 1 - Community
70
6. Federal Emergency Management Agency, Flood Insurance Study, Coweta
County, Georgia (Unincorporated Areas), Flood Insurance Study, February 2,
1982; Flood Insurance Rate Map, August 2, 1982.
7. Federal Emergency Management Agency, Flood Insurance Study, Coweta
County, Georgia (Unincorporated Areas), September 8, 1999.
8. Federal Emergency Management Agency, Guidelines and Specifications for
Flood Hazard Mapping Partners, 2003.
9. Federal Emergency Management Agency, Flood Insurance Study, Coweta
County, Georgia and Incorporated Areas, May 16, 2006.
10. Interagency Advisory Committee on Water Data, Guidelines for determining
flood flow frequency: Bulletin 17B of the Hydrology Subcommittee, Office of
Water Data Coordination, U.S. Geological Survey, Reston, VA, 1982.
11. Jack W. Berry & Associates, Inc., Aerial Photographs, Coweta County,
Georgia, Scale 1:12,000, 1977a.
12. Jack W. Berry & Associates, Inc., Topographic Maps, Scale 1:4,800, Contour
Interval 5 feet: Coweta County, Georgia, 1977b.
13. NGS: VERTCON-North American Vertical Datum Conversion Utility.
Retrieved on November 18, 2004, from http://www.ngs.noaa.gov/
14. Photo Science, Inc., Coweta County countywide topographic LiDAR dataset,
2007.
15. U.S. Army Corps of Engineers, Hydrologic Engineering Center, HEC-2 Water
Surface Profiles, Davis, California, November 1976, revised April 1984.
16. U.S. Department of Agriculture, Soil Conservation Service, Technical Release
No. 20, Computer Program, Project Formulation, Hydrology, Washington,
D.C., May 1965.
17. U.S. Department of Agriculture, Soil Conservation Service, Technical Release
No. 55, Urban Hydrology for Small Watersheds, 1975.
18. U.S. Department of Agriculture, Natural Resources Conservation Service,
Technical Release No. 55, Urban Hydrology for Small Watersheds, 1986.
19. U.S. Department of Agriculture, Natural Resources Conservation Service,
Hydrographs, National Engineering Handbook, Part 630 Hydrology: Chapter
16, 2007.
71
20. U.S. Department of Housing and Urban Development, Federal Insurance
Administration, Flood Hazard Boundary Map, Coweta County, Georgia
(Unincorporated Areas), Scale 1:24,000, April 1976.
21. U.S. Department of Urban and Housing Development, Federal Insurance
Administration, Flood Insurance Study, City of Newnan, Coweta County,
Georgia, May 15, 1978.
22. U.S. Geological Survey, 7.5-Minute Series Topographic Maps, Scale 1:24,000,
Contour Interval 20 Feet: Brooks, Georgia, 1965; Fairburn, Georgia, 1954,
photorevised 1968 and 1973; Grantville, Georgia, 1964, photorevised 1973;
Haralson, Georgia, 1971; Hogansville, Georgia, 1964, photorevised 1973;
Hollonville, Georgia 1971; Lowell, Georgia, 1964; Lutherville, Georgia, 1971;
Madras, Georgia, 1965, photorevised 1973; Newnan North, Georgia, 1965,
photorevised 1973; Newnan South, Georgia, 1965, photorevised 1973; Newnan
SW, Georgia 1965; Palmetto, Georgia, 1954, photorevised 1968; Rico,
Georgia, 1958, photorevised, 1968; Senoia, Georgia, 1965; Sharpsburg,
Georgia, 1965; Tyrone, Georgia, 1965; Whitesburg, Georgia, 1965.
23. U.S. Geologic Survey, Flood-Frequency Analysis for Small Natural Streams in
Georgia by H.G. Golden and McG. Price, July 1976
24. U.S. Geological Survey, Preliminary Flood-Frequency Relations, Urban
Streams, Metropolitan Atlanta, Georgia by V.B. Sauer, Atlanta, Georgia,
unpublished.
25. U.S. Geological Survey, Flood-Frequency Relations for Urban Streams in
Georgia, 1994 Update, Atlanta, Georgia, 1995.
26. U.S. Geological Survey, The National Flood-Frequency Program – Methods for
Estimating Flood Magnitude and Frequency in Rural and Urban Areas in
Georgia, 1999.
27. U.S. Geological Survey, Magnitude and frequency of rural floods in the
southeastern United States, 2006: Volume 1, Georgia by A.J. Gotvald, T.D.
Feaster, and J.C. Weaver, 2009.
28. U.S. Weather Bureau, Technical Paper No. 40, Rainfall Frequency Atlas of the
United States, 1961.
600
620
640 640
660 660
680 680
700 700
720 720
740 740
760 760
780 780
47.50 48.00 48.50 49.00 49.50 50.00 50.50 51.00 51.50 52.00 52.50 53.00 53.50 54.00
ELE
VA
TIO
N IN
FEET
(N
AV
D 8
8)
STREAM DISTANCE IN MILES FROM WEST POINT DAM
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
FLO
OD
PR
OFIL
ES
CH
AT
TA
HO
OC
HEE R
IVER
05P
AF AG AH AI
AJ AK
CO
UN
TY
BO
UN
DA
RY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
LIM
IT O
F F
LOO
DIN
G A
FFEC
TIN
G C
OM
MU
NIT
Y
620
640
660 660
680 680
700 700
720 720
740 740
760 760
780 780
800 800
54.00 54.50 55.00 55.50 56.00 56.50 57.00 57.50 58.00 58.50 59.00 59.50 60.00 60.50
ELE
VA
TIO
N IN
FEET
(N
AV
D 8
8)
STREAM DISTANCE IN MILES FROM WEST POINT DAM
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
FLO
OD
PR
OFIL
ES
CH
AT
TA
HO
OC
HEE R
IVER
06P
AL AM AN AO AP AQ AR AS AT
AU
ST
AT
E R
OU
TE 1
6
CO
NFL
UEN
CE O
F T
HO
MA
S C
REEK
CO
NFL
UEN
CE O
F M
OO
RE C
REEK
CO
NFL
UEN
CE O
F W
AH
OO
CR
EEK
CO
NFLU
EN
CE O
F C
ED
AR
CR
EEK
RA
ILR
OA
D
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
620
640
660 660
680 680
700 700
720 720
740 740
760 760
780 780
800 800
60.50 61.00 61.50 62.00 62.50 63.00 63.50 64.00 64.50 65.00 65.50 66.00 66.50 67.00
ELE
VA
TIO
N IN
FEET
(N
AV
D 8
8)
STREAM DISTANCE IN MILES FROM WEST POINT DAM
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
FLO
OD
PR
OFIL
ES
CH
AT
TA
HO
OC
HEE R
IVER
07P
AV AW
CO
UN
TY
BO
UN
DA
RY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
LIM
IT O
F F
LOO
DIN
G A
FFEC
TIN
G C
OM
MU
NIT
Y
740
745
750 750
755 755
760 760
765 765
770 770
775 775
780 780
785 785
0 500 1000 1500 2000 2500 3000 3500 4000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
FLO
OD
PR
OFI
LES
KEG
CR
EEK
08P
*LI
MIT
OF D
ET
AIL
ED
ST
UD
Y
LEGEND
0.2% ANNUAL CHANCE FLOOD*
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD*
10% ANNUAL CHANCE FLOOD*
STREAM BED
CROSS SECTION LOCATION
HUTCHINS LAKE FREEMAN LAKE
* DATA NOT AVAILABLE* LIMIT OF DETAILED STUDY IS APPROXIMATELY
40 FEET UPSTREAM OF ROCKAWAY ROAD
750
755
760 760
765 765
770 770
775 775
780 780
785 785
790 790
795 795
4000 4500 5000 5500 6000 6500 7000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE *LIMIT OF DETAILED STUDY
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
FLO
OD
PR
OFI
LES
KEG
CR
EEK
09P
LIM
IT O
F D
ET
AIL
ED
ST
UD
Y
LEGEND
0.2% ANNUAL CHANCE FLOOD*
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD*
10% ANNUAL CHANCE FLOOD*
STREAM BED
CROSS SECTION LOCATION
* DATA NOT AVAILABLE 40 FEET UPSTREAM OF ROCKAWAY ROAD
* LIMIT OF DETAILED STUDY IS APPROXIMATELY
770
780
790 790
800 800
810 810
820 820
830 830
840 840
850 850
860 860
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
LIT
TLE
WA
HO
O C
REEK
25P
A B C
D
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
RO
SC
OE R
OA
D
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
780
790
800 800
810 810
820 820
830 830
840 840
850 850
860 860
870 870
6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
LIT
TLE
WA
HO
O C
REEK
26P
E F
G H
FA
ST
GU
AR
D F
AR
MS
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
800
810
820 820
830 830
840 840
850 850
860 860
870 870
880 880
890 890
13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
LIT
TLE
WA
HO
O C
REEK
27P
I J K L
M
BR
IDG
E
BR
IDG
E
BR
IDG
E
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
830
840
850 850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
19000 19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
LIT
TLE
WA
HO
O C
REEK
28P
N O
LIM
IT O
F S
TU
DY
PO
ND
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
855
860
865 865
870 870
875 875
880 880
885 885
890 890
895 895
900 900
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH LINE CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y,
GA
AN
D I
NC
OR
PO
RA
TED
AR
EA
S
F LO
OD
PR
OFI
LES
PEEK
S C
REEK
36P
A B C D E
F
CO
NFL
UEN
CE W
ITH
LIN
E C
REEK
1% ANNUAL CHANCE BACKWATER EFFECTS FROM LINE CREEK
FLOODING CONTROLLED BY LINE CREEK
CO
LLIN
SW
OR
TH
RO
AD
LIM
IT O
F D
ET
AIL
ED
ST
UD
Y
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
770
780
790 790
800 800
810 810
820 820
830 830
840 840
850 850
860 860
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
SN
AK
E C
REEK
51P
A B
C
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
790
800
810 810
820 820
830 830
840 840
850 850
860 860
870 870
880 880
6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
SN
AK
E C
REEK
52P
D
E F
NEW
NA
N B
YP
AS
S
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
820
830
840 840
850 850
860 860
870 870
880 880
890 890
900 900
910 910
13000 13500 14000 14500 15000 15500 16000 16500 17000 17500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
SN
AK
E C
REEK
53P
G H I J K L
HO
SP
ITA
L R
OA
D
CH
RIS
TIA
N D
RIV
E
PA
RK
VIE
W D
RIV
E
TA
LIA
FER
RO
DR
IVE
CO
NFL
UEN
CE O
F T
RIB
UT
AR
Y 1
TO
SN
AK
E C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
CULVERT
CULVERT
870
880
890 890
900 900
910 910
920 920
930 930
940 940
950 950
960 960
17500 18000 18500 19000 19500 20000 20500 21000 21500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
SN
AK
E C
REEK
54P
M N O P
Q
R S T
LIM
IT O
F S
TU
DY
WIL
LOW
DR
IVE
DIX
ON
ST
REET
CU
LVER
T
CU
LVER
T
CU
LVER
T
CO
NFL
UEN
CE O
F T
RIB
UT
AR
Y 2
TO
SN
AK
E C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
COWETA COUNTY
COWETA COUNTY, GEORGIA
AND INCORPORATED AREAS Community Community Name Number COWETA COUNTY (UNINCORPORATED AREAS) 130298 GRANTVILLE, CITY OF 130443 HARALSON, TOWN OF 130299 MORELAND, TOWN OF 130300 NEWNAN, CITY OF 130062 SENOIA, CITY OF 130301
∗SHARPSBURG, TOWN OF 130581 TURIN, TOWN OF 130475
∗ Non-Floodprone
Revised: February 6, 2013
FLOOD INSURANCE STUDY NUMBER
13077CV002B
VOLUME 2 OF 2
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) report may not contain all
data available within the Community Map Repository. Please contact the
Community Map Repository for any additional data.
The Federal Emergency Management Agency (FEMA) may revise and republish
part or all of this FIS report at any time. In addition, FEMA may revise part of
this FIS report by the Letter of Map Revision process, which does not involve
republication or redistribution of the FIS report. Therefore, users should consult
with community officials and check the Community Map Repository to obtain the
most current FIS report components.
Initial Countywide FIS Effective Date: May 16, 2006
Revised Countywide FIS Effective Date: February 6, 2013
i
TABLE OF CONTENTS
Volume 1
1.0 INTRODUCTION.............................................................................................. 1
1.1 Purpose of Study .......................................................................................... 1
1.2 Authority and Acknowledgements ................................................................ 1
1.3 Coordination ................................................................................................ 2
2.0 AREA STUDIED ............................................................................................... 3
2.1 Scope of Study ............................................................................................. 3
2.2 Community Description ............................................................................... 6
2.3 Principal Flood Problems ............................................................................. 7
2.4 Flood Protection Measures ........................................................................... 7
3.0 ENGINEERING METHODS ............................................................................ 8
3.1 Hydrologic Analyses .................................................................................... 8
3.2 Hydraulic Analyses .................................................................................... 23
3.3 Vertical Datum ........................................................................................... 25
4.0 FLOODPLAIN MANANGEMENT APPLICATIONS .................................. 26
4.1 Floodplain Boundaries ............................................................................... 26
4.2 Floodways .................................................................................................. 27
5.0 INSURANCE APPLICATIONS ..................................................................... 67
6.0 FLOOD INSURANCE RATE MAP ............................................................... 67
7.0 OTHER STUDIES ........................................................................................... 68
8.0 LOCATION OF DATA ................................................................................... 68
9.0 BIBLIOGRAPHY AND REFERENCES ........................................................ 68
ii
TABLE OF CONTENTS
Volume 1 (continued)
FIGURES
Figure 1 – Floodway Schematic .......................................................................................... 28
TABLES
Table 1 – Stream Studied by Detailed Methods ..................................................................... 3
Table 2 – Streams Name Changes ......................................................................................... 5
Table 3 – Summary of Discharges ....................................................................................... 10
Table 4 – Manning’s “n” Values.......................................................................................... 24
Table 5 – Vertical Datum Conversion .................................................................................. 25
Table 6 – Floodway Data Table ........................................................................................... 29
Table 7 – Community Map History ..................................................................................... 69
EXHIBITS
Exhibit 1 - Flood Profiles
Chandlers Creek Panels 01P-04P
Chattahoochee River Panels 05P-07P
Keg Creek Panels 08P-09P
Lake Amlajack Creek Panels 10P-11P
Lake Summergrove Branch Panel 12P
Line Creek Panels 13P-22P
Little Creek Panels 23P-24P
Little Wahoo Creek Panels 25P-28P
Mineral Spring Branch Panels 29P-33P
Paradise Lakes Branch Panels 34P-35P
Peeks Creek Panel 36P
Persimmon Creek Panels 37P-39P
Sandy Creek Panels 40P-45P
Shoal Creek Panels 46P-50P
Snake Creek Panels 51P-54P
Tributary 1 to Line Creek Panels 55P-56P
Tributary 1 to Mineral Spring Branch Panels 57P-60P
iii
TABLE OF CONTENTS
Volume 2
EXHIBITS (continued)
Exhibit 1 - Flood Profiles
Tributary 1 to Persimmon Creek Panels 61P-62P
Tributary 1 to Sandy Creek Panels 63P-64P
Tributary 1 to Shoal Creek Panel 65P
Tributary 1 to Snake Creek Panel 66P
Tributary 1 to Turkey Creek Panel 67P
Tributary 1 to Wahoo Creek Panel 68P
Tributary 1 to White Oak Creek Panels 69P-70P
Tributary 2 to Mineral Spring Branch Panels 71P-74P
Tributary 2 to Sandy Creek Panels 75P-76P
Tributary 2 to Shoal Creek Panels 77P-78P
Tributary 2 to Snake Creek Panel 79P
Tributary 2 to Wahoo Creek Panels 80P-81P
Tributary 3 to Sandy Creek Panels 82P-83P
Tributary 3 to Shoal Creek Panels 84P- 85P
Tributary 3 to Wahoo Creek Panel 86P
Tributary 4 to Wahoo Creek Panel 87P
Tributary 5 to Wahoo Creek Panel 88P
Tributary 6 to Wahoo Creek Panel 89P
Tributary 7 to Wahoo Creek Panel 90P
Tributary 8 to Wahoo Creek Panel 91P
Tributary 9 to Wahoo Creek Panel 92P
Tributary 10 to Wahoo Creek Panel 93P
Tributary 11 to Wahoo Creek Panel 94P
Tributary 12 to Wahoo Creek Panel 95P
Turkey Creek Panels 96P-101P
Wahoo Creek Panels 102P-114P
White Oak Creek Panels 115P-120P
Exhibit 2 - Flood Insurance Rate Map Index
Flood Insurance Rate Map
840
850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
0 500 1000 1500 2000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SNAKE CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y ,
GA
AN
D IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
1 T
O S
NA
KE C
REEK
66P
A B C D
CO
NFL
UEN
CE W
ITH
SN
AK
E C
REEK
LIM
IT O
F S
TU
DY
PIC
KEN
S D
RIV
E
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM SNAKE CREEK
CULVERT
810
830
850 850
870 870
890 890
910 910
930 930
950 950
970 970
990 990
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
1 T
O W
AH
OO
CR
EEK
68P
A B C D E F G
H I J
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
VET
ER
AN
S C
LUB
RO
AD
WA
HO
O H
ILL
RO
AD
MIL
LAR
D F
AR
MER
IN
DU
ST
RIA
L B
OU
LEV
AR
D
OV
ER
BR
OO
K C
OU
RT
WO
OD
TR
AIL
WEIR
ST
RU
CT
UR
E
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
CULVERT
CULVERT
CULVERT
CULVERT
870
880
890 890
900 900
910 910
920 920
930 930
940 940
950 950
960 960
0 500 1000 1500 2000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH SNAKE CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
2 T
O S
NA
KE C
REEK
79P
A B C D E F
CO
NFL
UEN
CE W
ITH
SN
AK
E C
REEK
LIM
IT O
F S
TU
DY
WIL
LOW
DR
IVE
MA
PLE
DR
IVE
MA
PLE
DR
IVE
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM SNAKE CREEK
CULVERT
CULVERT
CULVERT
840
850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
2 T
O W
AH
OO
CR
EEK
80P
A B C D E F G H
I J
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
BU
LLS
BO
RO
DR
IVE
AS
HL E
Y P
AR
K B
OU
LEV
AR
D
AS
HLE
Y P
AR
K D
RI V
E
BU
LLS
BO
RO
DR
IVE
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 3
TO
WA
HO
O C
REEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 5
TO
WA
HO
O C
REEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 6
TO
WA
HO
O C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
CULVERT
CULVERT
CULVERT
CULVERT
880
890
900 900
910 910
920 920
930 930
940 940
950 950
960 960
970 970
5500 6000 6500 7000 7500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
2 T
O W
AH
OO
CR
EEK
81P
K L M N
LIM
IT O
F S
TU
DY
PA
RK
ING
LO
T
JEFFE
RS
ON
ST
REET
CO
WET
A C
RO
SS
ING
SH
OP
PIN
G C
EN
TER
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT CULVERT
850
860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
940 940
0 500 1000 1500 2000 2500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TRIBUTARY 2 TO WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
3 T
O W
AH
OO
CR
EEK
86P
A B C D E
CO
NFL
UEN
CE W
ITH
TR
IBU
TA
RY
2 T
O W
AH
OO
CR
EEK
LIM
IT O
F S
TU
DY
BU
LLS
BO
RO
DR
IVE
CU
LVER
T
MA
TA
DO
R W
AY
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 4
TO
WA
HO
O C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
CULVERT
855
860
865 865
870 870
875 875
880 880
885 885
890 890
895 895
900 900
0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TRIBUTARY 3 TO WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
4 T
O W
AH
OO
CR
EEK
87P
A B C D
CO
NFL
UEN
CE W
ITH
TR
IBU
TA
RY
3 T
O W
AH
OO
CR
EEK
LIM
IT O
F S
TU
DY
DET
EN
TIO
N P
ON
D
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
865
870
875 875
880 880
885 885
890 890
895 895
900 900
905 905
910 910
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TRIBUTARY 2 TO WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
5 T
O W
AH
OO
CR
EEK
88P
A B
CO
NFL
UEN
CE W
ITH
TR
IBU
TA
RY
2 T
O W
AH
OO
CR
EEK
LIM
IT O
F S
TU
DY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
870
875
880 880
885 885
890 890
895 895
900 900
905 905
910 910
915 915
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TRIBUTARY 2 TO WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
6 T
O W
AH
OO
CR
EEK
89P
A B
CO
NFL
UEN
CE W
ITH
TR
IBU
TA
RY
2 T
O W
AH
OO
CR
EEK
LIM
IT O
F S
TU
DY
AS
HLE
Y P
AR
K D
RI V
E
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
840
850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
0 500 1000 1500 2000 2500 3000 3500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
7 T
O W
AH
OO
CR
EEK
90P
A B C D E
F
G H
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
CU
LVER
TJEFFE
RS
ON
ST
REET
MA
RA
TH
ON
ST
REET
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
CULVERT
840
850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
8 T
O W
AH
OO
CR
EEK
91P
A B C D
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
860
870
880 880
890 890
900 900
910 910
920 920
930 930
940 940
950 950
0 500 1000 1500 2000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
9 T
O W
AH
OO
CR
EEK
92P
A B C
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
870
880
890 890
900 900
910 910
920 920
930 930
940 940
950 950
960 960
0 500 1000 1500 2000 2500 3000 3500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
10
TO
WA
HO
O C
REEK
93P
A B C D
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM WAHOO CREEK
850
860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
940 940
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
11
TO
WA
HO
O C
REEK
94P
A B C D E F
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
RO
BER
TS
RO
AD
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
880
890
900 900
910 910
920 920
930 930
940 940
950 950
960 960
970 970
0 500 1000 1500 2000 2500 3000 3500 4000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH WAHOO CREEK
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
TR
IBU
TA
RY
12
TO
WA
HO
O C
REEK
95P
A B C D E F G H
CO
NFLU
EN
CE W
ITH
WA
HO
O C
REEK
LIM
IT O
F S
TU
DY
PIN
SO
N S
TR
EET
SA
VA
NN
AH
ST
REET
CA
LHO
UN
ST
REET
DEW
EY
ST
REET
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
CULVERT
CULVERT
660
670
680 680
690 690
700 700
710 710
720 720
730 730
740 740
750 750
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
102P
A B
CO
NFLU
EN
CE W
ITH
CH
AT
TA
HO
OC
HEE R
IVER
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
1% ANNUAL CHANCE BACKWATER EFFECTS FROM CHATTAHOOCHEE RIVER
660
670
680 680
690 690
700 700
710 710
720 720
730 730
740 740
750 750
6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
103P
C D E
WEIR
ST
RU
CT
UR
E
BR
IDG
E
WA
GER
S M
ILL
RO
AD
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
680
690
700 700
710 710
720 720
730 730
740 740
750 750
760 760
770 770
13000 13500 14000 14500 15000 15500 16000 16500 17000 17500 18000 18500 19000 19500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
104P
F G H
I
SW
EET
CH
AR
RIO
T R
OA
D
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
690
700
710 710
720 720
730 730
740 740
750 750
760 760
770 770
780 780
19500 20000 20500 21000 21500 22000 22500 23000 23500 24000 24500 25000 25500 26000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
105P
J K L
M
WELC
OM
E T
O S
AR
GEN
T R
OA
DLEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
710
720
730 730
740 740
750 750
760 760
770 770
780 780
790 790
800 800
26000 26500 27000 27500 28000 28500 29000 29500 30000 30500 31000 31500 32000 32500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
106P
N O P Q
R
HEN
RY
BR
YA
NT
RO
AD
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
750
760
770 770
780 780
790 790
800 800
810 810
820 820
830 830
840 840
30000 30500 31000 31500 32000 32500 33000 33500 34000 34500 35000 35500 36000 36500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
107P
S T U
V
RA
ILR
OA
D
ST
AT
E H
IGH
WA
Y 1
6
BIB
BS
LA
KE D
AM
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
750
760
770 770
780 780
790 790
800 800
810 810
820 820
830 830
840 840
36500 37000 37500 38000 38500 39000 39500 40000 40500 41000 41500 42000 42500 43000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
108P
W X
Y
WIT
CH
ER
RO
AD
CO
NFL
UEN
CE O
F S
NA
KE C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
770
780
790 790
800 800
810 810
820 820
830 830
840 840
850 850
860 860
43000 43500 44000 44500 45000 45500 46000 46500 47000 47500 48000 48500 49000 49500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
109P
Z AA
CO
NFLU
EN
CE O
F L
ITT
LE W
AH
OO
CR
EEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
780
790
800 800
810 810
820 820
830 830
840 840
850 850
860 860
870 870
49500 50000 50500 51000 51500 52000 52500 53000 53500 54000 54500 55000 55500 56000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
110P
AB AC AD
RO
SC
OE R
OA
D
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
800
810
820 820
830 830
840 840
850 850
860 860
870 870
880 880
890 890
55500 56000 56500 57000 57500 58000 58500 59000 59500 60000 60500 61000 61500 62000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
111P
AE AF AG AH AI
AJ
TH
E B
OU
LEV
AR
D
WEIR
ST
RU
CT
UR
E
OLD
AT
LAN
TA
HIG
HW
AY
JA
CK
SO
N S
TR
EET
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 1
TO
WA
HO
O C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
825
835
845 845
855 855
865 865
875 875
885 885
895 895
905 905
915 915
62000 62500 63000 63500 64000 64500 65000 65500 66000 66500 67000 67500 68000 68500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
112P
AK AL AM
AN
MIL
LAR
D F
AR
MER
IN
DU
ST
RIA
L B
OU
LEV
AR
D
RA
ILR
OA
D
JEFFE
RS
ON
ST
REET
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 2
TO
WA
HO
O C
REEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 7
TO
WA
HO
O C
REEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
CULVERT
840
850
860 860
870 870
880 880
890 890
900 900
910 910
920 920
930 930
68000 68500 69000 69500 70000 70500 71000 71500 72000 72500 73000 73500 74000 74500
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
113P
AO AP
AQ AR
BU
LLS
BO
RO
DR
IVE
GR
EIS
ON
TR
AIL
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 8
TO
WA
HO
O C
REEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 9
TO
WA
HO
O C
REEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 1
0 T
O W
AH
OO
CR
EEK
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 1
1 T
O W
AH
OO
CR
EEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION
CULVERT
CULVERT
875
885
895 895
905 905
915 915
925 925
935 935
945 945
955 955
965 965
74500 75000 75500 76000 76500 77000 77500 78000 78500 79000 79500 80000 80500 81000
ELE
VA
TIO
N IN
FEET
(N
AV
D)
STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH CHATTAHOOCHEE RIVER
FED
ER
AL
EM
ER
GEN
CY
MA
NA
GEM
EN
T A
GEN
CY
CO
WET
A C
OU
NT
Y, G
AA
ND
IN
CO
RP
OR
AT
ED
AR
EA
S
FLO
OD
PR
OFI
LES
WA
HO
O C
REEK
114P
AS AT AU AV AW AX AY
LIM
IT O
F S
TU
DY
E B
RO
AD
ST
REET
CU
LVER
T
PA
UL
ST
REET
CO
NFLU
EN
CE O
F T
RIB
UT
AR
Y 1
2 T
O W
AH
OO
CR
EEK
LEGEND
0.2% ANNUAL CHANCE FLOOD
1% ANNUAL CHANCE FLOOD
2% ANNUAL CHANCE FLOOD
10% ANNUAL CHANCE FLOOD
STREAM BED
CROSS SECTION LOCATION