SW8060722_COMPLIANCE_20060816

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW C�Zao�
DOC TYPE
El CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
�C)�[Lp
WYYMMDD

WET DETENTION POND ANALYSIS
FILE NAME: S:IWQSIPOND1060722.WK1
PROJECT #: SW8 060722 REVIEWER: P.Bartlett ,.,_
PROJECT NAME:
[William- s W k
DATE:
16-Aug-06
Receiving Stream:
UT..Burgaw_C,rk
Class:
C; Sw
Drainage Basin:
Cape Fear
Index No.
1''8-74-39
Site Area
13.82 j acres
Drainage Area
5026.18.00 square feet
Area in Acres
11.54
IMPERVIOUS AREAS
Rational C
28 lots@3,870 sf ea.
Buildings
square feet
0.95
10836000
Parking
000,
square feet
0.95
SW
Streets
14154.00-
5763800'
square feet
square feet
0.95
0.95
40�
Other (PS)
1500.00
square feet
0.95
square feet
square feet
TOTAL
181652.00
square feet
Rational Cc= 0.47
SURFACE AREA CALCULATION
% IMPERVIOUS 36.14% SAIDA Ratio 3.19%
Des, Depth 4 Req. SA 16040 sf
TSS, 85 or 90: L90 Prov. SA 16948 sf
VOLUME CALCULATION * place a "1" in the box if Rational is used
Rational ?*
Des. Storm
1.00
inches
Rv=
0.375
Bottom
{:, 381
msl
Perm. Pool
L 42,00
msl
Design Pool
42:51 msf
Storage met @elev� 42.59 msl
Req. Volume
15718
cf
Vol. Prov. at DP
15738
cf
ORIFICE CALCULATION
FOREBAY
Perm. Pool Volume=
Req. Forebay Volume=
Provided Volume=
Percent=
Elevation Area
42.00. � 16948:00.
42.50 3628000
(slope at 20:1, vol = 15738
E 43562' 1
8712.4
8986.00 .
20.6%
Inc. Vol. Acc. Vol.
0.00
13307.00 13307.00
Avg. Head =
0.21
ft
Q2 Area =
5.96
sq. inches
Flow Q2, cfs
0.091
cfs
Q5 Area =
2.38
sq. inches
Flow Q5, cfs
0.036
cfs
Orifice Area
3.14
sq. inches
No. of Orifices
u 1.
Q=
0.048
cfs
Diameter, inches
2.00
weir H x W
in
x
F ." " "
in
Drawdown =
3.8
days
Surface Area @DP =
36280 sq. ft.
Falling Head Drawdown =
4.1 days
C= 3.290833333
L= -0.042
COMMENTS
Surface Area , Volume and Orifice are within Design Guidelines