SW8060211_COMPLIANCE_20060214

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
YYYYMMDD

DETENTION POND ANALYSIS FILENAME: G:\DATA\WPDATA\WQS\POND1060211.WK1
PROJECT#: SW8 060211 REVIEWER: P.Bartlett
PROJECT NAME: Tri-Coast Plaza
DATE: 14-Feb-06
Receiving Stream: Burgaw Creek Class: C; Sw
Drainage Basin: Cape Fear Index No. 18-74-39
Site Area 1.87 acres
Drainage Area square feet Area
1.87 acres
IMPERVIOUS AREAS
OS Bldgs
OS Prkg
OS Sidewalks
TOTAL
SURFACE AREA CALCULATION
14940.00 square feet
36260.00 square feet
3325.00 square feet
square feet
square feet
square feet
square feet
Rational C
o.�C� y'12/ac
Rational Cc= 0.07
% IMPERVIOUS
67.09%
SA/DA Ratio 5.71% -
Des. Depth
3
Req. SA 4640 sf
TSS,
85
Prov. SA ii8 sf
(50'vegetated filter provided)
VOLUME CALCULATION
place a "'I" in the box if Rational is used
Rational ?*
FOREBAY
Des. Storm
it
inches
Perm. Pool Volume=
5099
Rv=
0.65
Req. Forebay Volume=
1019.8
Bottom
41
msl
Provided Volurne=
1227.00
Perm. Pool
..........
1: i
msI
Percent=
Design Pool
45
msI
Design SA
5069
sf
Req. Volume
448
Gf
SA @
Prov. Volume
cf
Elevation=
ORIFICE CALCULATION
Avg. Head =
Flow Q2, cfs
Flow Q5, cfs
No. of Orifices
Diameter, inches
Drawdown =
0.48
ft
0.026
cfs
0.010
cfs
weir M x W
days
Q2 Area =
Q5 Area =
Orifice Area
Q=
in
COMMENTS
Surface Area , Volume and Orifice are within Design Guideline:
1.11
sq. in.
0.44
sq. in.
0.79
sq. in.
0.018
cfs
x
1:--':
in