final wake sw tool v22

8/8/2019 Final Wake Sw Tool v22

1/18Wake County Stormwater ToolVersion 2.2

09/09/2010 05:10:27

Stormwater Management Plan S/D No.: 0

0 Date: 12/30/1899

0 Designer: 0

SUMMARY INFORMATION

Site DataTotal Area: 0 acres

Zoning: 0

Number of Lots: 0

Percent Impervious: #DIV/0! %

Volume Management Calculations

Target Curve Number: 0

Proposed Curve Number: 0

Total Volume Required: #DIV/0!

Total Volume Provided: 0

Nitrogen Calculations

TN Loading from Site: #DIV/0! lbs/ac/yr

Buy-down (if in NRB): #DIV/0!

Peak Flow Management Calculations:

Pre-Development Peak Flow: #DIV/0! cfs

Post-Development Peak Flow: #DIV/0! cfs

ft3

ft3



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Stormwater Management Plan S/D No.:

Date:

Designer:

TARGET CURVE NUMBER CALCULATION

Wake County Target Curve Numbers

Zoning District A B C D

R-80W and R-80 37 60 73 79

R-40W and R-40 41 62 75 80

R-30, R-20, R-15, R-5 43 63 76 81

Site Data:Total Site Area: acres **Excludes Area of Exisitng Lakes or Ponds on site

Existing Lake/Pond Area: acres

Area used for Overall Density Calcs: 0 acres

Zoning District:

Soil Composition:Hydrologic Soil Group Site Area % Target CN

A #DIV/0! 43

B #DIV/0! 63

C #DIV/0! 76

D #DIV/0! 81

100%


Runoff (inches) = Q* = 0.00 inches



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Stormwater Management Plan S/D No.: 00 Date: 12/30/1899

0 Designer: 0

PRELIMINARY PLAN SUBMITTAL

Site Data:0 acres

Zoning District: 0

Number of Lots:

Total Area in R/W: acres

Impervious Area in R/W: acres

acres

acres

acres

%

Lot Data:

Total Lot Acreage: 0 acres

Impervious Area per Lot: sf

0 %

acresAverage Lot Size: #DIV/0! sf

Average Percent Impervious per Lot: #DIV/0! %

#DIV/0! %

Stormwater Calculations:

Woods #DIV/0! #DIV/0!

Grass/Lawn #DIV/0! #DIV/0! A

Impervious #DIV/0! #DIV/0! B

#DIV/0! D


Results:

#DIV/0!cf

Preliminary Total Nitrogen

#DIV/0! lbs/ac/yr

R=

Total Site Area:(Excluding Area in Existing Water Bodies)

reserve oo e rea:(Common Open Space to remain woods

or be reforested; Stream Buffers not onlots.)

Managed Open Space:(Grassed Common Open Space)

Other Impervious Surface:(Impervious not on lots or in R/W)

Percent of Total Imperviousthat is Disconnected:

(50% is default. See Table 3.3.)

Assumed Wooded Area:(Design Manual Table 3.1)

Additional Wooded Area:(Stream Buffer or Additional wooded area on lots.

Must be recorded on Plat.)

Percent Impervious for site*:*Using total site area plus existing lakes/ponds

Weighted CN1

Proposed Curve Number:1

1 Weighted CN method represents the CN when the landuse is evenly distributed among all on-site soils (w/exemption of R/W which is D soils); It is an approximatecurve number for Post-development and should be treated as such.

Storage Volume Required:(Approximate locations shown on Preliminary Plan)

Loading from Site:2 CNp=

2 Preliminary nitrogen loading does not include any reductions by BMPs. If loading is above3.6 lbs/ac/yr - BMPs or a buydown will be required.



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0 Date:

0 Designer:

POST-DEVELOPMENT CALCULATIONS

CURVE NUMBER:

Is Data from Preliminary Plan Still Valid?Total Area of Lots: acres

Number of Lots:

Impervious Area per Lot: sf % Impervious on Lots: #DIV/0! %

% Woods on Lots: %

% Impervious in R/W: %

#DIV/0! %

Percent of Total Disconnected Impervious: 50

HSG Land-use CN Area (acres) %0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

0 #DIV/0!

Totals: 0 #DIV/0!

Post-Development CN = 0

Runoff (inches) = Q* = 0.00 inches

Warnings/Notes:

#DIV/0!

Percent Impervious for Site*:*Using total site area plus existing lakes/ponds

% (50% is Default. See Table 3.3)


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Wake County Stormwater Tool 09/09/2010 05:10:28



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Y

N

Totals

% R/W Dis?

A


7/18Wake County Stormwater ToolVersion 2 2

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0 Date: 12/30/1899

0 Designer: 0

PRE-DEVELOPMENT CALCULATIONS

CURVE NUMBER:

HSG Land-use CN Area (acres) %

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!

98 #DIV/0!98 #DIV/0!

98 #DIV/0!

User Defined #DIV/0!




Totals: 0 #DIV/0!

Pre-development CN = #DIV/0!

Runoff (inches) = Q* = #DIV/0! inches

TIME OF CONCENTRATION:

Length (ft) Slope (ft/ft) Surface Cover

Sheet Flow:

Sheet Flow:

Shallow Flow:

Shallow Flow:

Length (ft) Slope (ft/ft) n-value Wetted Perimeter (ft)

Channel Flow:

Channel Flow:

0.08 hrs (Minimum 5 minutes)

Tt(hrs)

FlowArea (ft2) Tt (hrs)

Pre-development Tc

=



09/09/2010 05:10:28


0 Date: 12/30/1899

0 Designer: 0


Length (ft) Slope (ft/ft) Surface Cover

Sheet Flow:

Sheet Flow:

Shallow Flow:

Shallow Flow:

Length (ft) Slope (ft/ft) n-value Wetted Perimeter (ft)

Channel Flow:

Channel Flow:

0.08 hrs (Minimum 5 minutes)

POST-DEVELOPMENT CALCULATIONS

Tt(hrs)

FlowArea (ft2) Tt (hrs)

Post-development Tc

=



09/09/2010 05:10:28


0 Date: 12/30/1899

0 Designer: 0

PEAK FLOW CALCULATIONS

CURVE NUMBER:

Pre-development CN = #DIV/0!

#DIV/0!


0.08 hrs

0.08 hrs

PEAK FLOW:

Method: TR-55 Graphical Peak Discharge Method for Type II Distribution

Where:

Q* = runoff (inches)

Pre-development

#DIV/0! csm/in

0.00

Q* = #DIV/0! inches

#DIV/0!cfs

Post-development

#DIV/0! csm/in

0.00

Q* = #DIV/0! inches

#DIV/0!cfs

#DIV/0!

Post-Development CNadj

=

Pre-development Tc

=

Post-development Tc

=

Qp

= quA

mQ*

Qp

= Peak Discharge (cfs)

qu

= Unit peak discharge (csm/in) TR-55 Appendix F

Am

= Drainage Area (mi2)

qu

=

Am

= mi2

Q1-year

=

qu

=

Am

= mi2

Q1-year

=



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0 Date:

0 Designer:

PROPOSED STORAGE DEVICES

Name/Location Type of Device Additional Comment

1

2

3

4

5

6

7

8

910

11

12

13

14

15

16

17

18

19

20

Total Volume Provided: 0#DIV/0! #DIV/0! #DIV/0!

0

#DIV/0!

Total Volume Required: #DIV/0!

Post-Development Curve Number Adjustment based on Volume Provided

Source: "Modeling Infiltration Practices Using TR-20", October, 1983, Maryland Department of the Environment

200

Where:

P = Rainfall (inches) = 3 inches

Q = Runoff Depth for Proposed CN (Q*) - Volume Provided (inches)

Volume Provided (Inches) = #DIV/0! inches

Q* = 0.00 inches

Q = #DIV/0! inches

#DIV/0!

Enter only runoff volume below that will be infiltrated or drawn down over 2 to 5 days. Avolume provided in devices should not be entered in this worksheet.

Storage VolumeProvided (ft3)

ft3

Volume Required by WakeCounty Ordinance: ft3

Minimum Volume Required to Meet PeakFlows for Neuse Rules: ft3

ft3

CNadj

=(P+2Q+2) - (5PQ+4Q2)1/2

Post-Development CNadj =


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#DIV/0!

ditional


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NITROGEN CALCULATIONS

Type of Land Cover Area (acres)

0.00 0.60 0.00

#DIV/0! 1.20 #DIV/0!

#DIV/0! 21.20 #DIV/0!

TOTAL 0.00 #DIV/0!

Nitrogen Loading w/out BMP Reductions: #DIV/0! lbs/ac/yr

Neuse Buy-down w/out BMP Reductions: #DIV/0!

Nitrogen Loading with BMP Reductions

See Wake County Stormwater Design Manual Chapter 4 for Details

Drainage Area 1:


Permanently protected open space 0.60 0.00

Managed open space 1.20 0.00

Impervious surfaces 21.20 0.00

TOTAL 0.00 0.00

Nitrogen Removal Efficiency of BMP(s) %

Nitrogen Loading for DA 1: 0.00 lbs/ac/yr

Drainage Area 2:





TOTAL 0.00 0.00

Nitrogen Removal Efficiency of BMP(s) %

Nitrogen Loading for DA 2: 0.00 lbs/ac/yr

Drainage Area 3:





TOTAL 0.00 0.00

Nitrogen Removal Efficiency of BMP(s) %Nitrogen Loading for DA 3: 0.00 lbs/ac/yr

Final Nitrogen Loading from Site: #DIV/0! lbs/ac/yr

TN exportcoefficient

(lbs/ac/yr)

TN exportfrom use

(lbs/yr)

Permanently protected undisturbed openspace (forest, unmown meadow)

Permanently protected managed openspace (grass, landscaping, etc.)

Impervious surfaces (roads, parking lots,driveways, roofs, etc.)

TN coeff.(lbs/ac/yr)

TN export(lbs/yr)


TN export(lbs/yr)


TN export(lbs/yr)



09/09/2010 05:10:29

Buy-down (Neuse Only):#DIV/0!



09/09/2010 05:10:29

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0


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final wake sw tool v22

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