SW6100701_Supplement Form_20120606

Permit No. 'S W4 /0o • � {
fb be provided by DWQ)
ATM o�oF w a r�gp�r
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filed out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
!. PROJECT INFORMATION"• ...` .
Project name Traemoor ViUage
Contact person Fleet Temple, Enoch Engineers, PA
Phone number 919-894-7765
Date 5/912012
Drainage area number 1
11. DESIGN INFORMATION
Site Characteristics
Drainage area
2,831,400 ft
Impervious area, post -development
1,675.669 ft
% impervious
59.18 %
Design rainfall depth
1.0 in
Storage Volume: Non -SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre -development 1-yr, 24-hr runoff
Post -development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the prelpost control of the iyr 24hr stone peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre -development
Rational C, post -development
Rainfall intensity: 1-yr, 24-hr storm
Pre -development 1-yr, 24-hr peak flow
Posi-development 1-yr, 24-hr peak flow
PrelPost 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the peen. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment deanout, bottom elevation
Sediment stbrage provided
Is there additional volume stored above the state -required temp. pool?
Elevation of the top of the additional volume
137,559 ft3
510,482 fl3
fl3
fl3
fl3
fl3
fl3
y (Y or N)
3.0 in
OK
OK, volume provided is equal to or in excess of volume required.
0.35 (unitfess)
0.64 (unitless)
2.10 inlhr OK
47.78 ft3lsec
44.03 ft3lsec
-3.75 ft3lsec
177.00 fmsl
173,50 fmsl
�3z6.A9-fersl� 1 ? 3 . Sd
174.00 fmsl
n
f F,4 '%( S ?.E?Otz-(
173.00. fmsl Data not needed for calculation option #1, but OK if provided.
169.50 imsl
168,50 fmsl Data nob needed for calculation option #1, but OK if provided.
1.00 ft
(Y or N)
177.0 fmsl OK
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Form SW401-Wet Detenfion Basin-Rev.6-9117f09 Pails i. & It. Design Summary, Page 1 of 2

Permit No.
(to be provided by DINO)
Ill.- DESIGN INFORMATION
Surface Areas
Area, temporary pool
161,488 fly
Area REQUIRED, permanent pool
99,099 ft
SAIDA ratio
3.50 (unitless)
Area PROVIDED, permanent pool, Ao,,,,
119,926 ft
OK
Area, bottom of 1 Oft vegetated shelf, Ab, r_mm
79,311 W
Area, sediment deanout, top elevation (bottom of pond), Abayo a
65,775 ft'
Volumes
Volume, temporary pool
510,482 ft'
OK
Volume, permanent pool, Vim,,,,-.
358,070 ft3
Volume, forebay (sum of forebays if more than one forebay)
71,704 ft�
Forebay % of permanent pool volume
20.0% %
OK
SA1DA Table Data
Design TSS removal
90 %
Coastal SAIDA Table Used?
n JY or N)
Mountain/Piedmont SAIDA Table Used?
y (Y or N)
SAIDA ratio
3.50 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
y (Y or N)
Volume, permanent pool, Vim, ,d
358,070 W
Area provided, permanent pool, A,,,,,_Pw
119,926 ft`
Average depth calculated
3.00 It
OK
Average depth used in SAIDA, d., (Round to nearest 0.5ft)
3.0 ft
OK
Calculation option 2 used? (See Figure 10-2b)
n (Y or N)
Area provided, permanent pool, A,,,,,_pd
119,926 W
Area, bottom of 10ft vegetated shelf, A ,w
79,311 ft
Area, sediment deanout, top elevation (bottom of pond), Abd , a
65,775 fe
'Depth" (distance b/w bottom of 10ft shelf and top of sediment)
3.50 ft
Average depth calculated
ft
Average depth used in SAIDA, d. (Round to nearest 0.511)
ft
Drawdown Calculations
Drawdown through orifice?
y (Y or N)
Diameter of orifice (if circular)
5.00 in
Area of orifice (if -non -circular)
in?
Coefficient of discharge (CD)
0,60 (unidess)
Driving head (Ho)
0.55 ft
Drawdown through weir?
n (Y or N)
Weir type
(unifless)
Coefficient of discharge (C.)
(unidess)
Length of weir (L)
ft
Driving head (H)
It
Pre -development 1-yr, 24-hr peak flow
47.78 Wlsec
Post -development 1-yr, 24-hr peak flow
1.66 ft3lsec
Storage volume discharge rate (through discharge orifice or weir)
1.66 elsec
Storage volume drawdown time
3.20 days
OK, draws down in 2-5 days.
Add'Rional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 It
OK
Length of flowpath to width ratio
7 :1
OK
Length to width ratio
7.0 :1
OK
Trash rack for overflow & orifice?
y (Y or N)
OK
Freeboard provided
1.5 ft
OK
Vegetated filter provided?
n (Y or N)
OK
Recorded drainage easement provided?
y (Y or N)
OK
Capures all runoff at ultimate build -out?
y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
Form SW401-Wet Detention Basin-Rev.e-9117109 Puts I. & 11. Design Summary, Page 2 of 2