SW8111203_COMPLIANCE_20120202

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW$""��O-3
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
YYYYMMDD

WET DETENTION POND ANALYSIS - ALL RULES
FILE NAME:
S:IWQSISTORMWATERIEXCELSPREADSHEETSIPOND1111203
PROJECT #: SW8
1111203 1
REVIEWER:
c. baker
Initial Run Date
fe, b. 2, 2012
PROJECT NAME:
State Employees Credit Union
Last modified
02-Feb-12
Receiving Stream;
lGibbs Creek
Class:
ISA
Drainage Basin:
LWhite Oak
Within 112 mile SA?
Site Area
ODrainage Area
Rules- "2008" or "Ph2"
IMPERVIOUS AREAS - BUA
Buildings
Street
SW
Future
Offsite
Other
TOTAL
Index No. 121-35-1-10 I
2.87 JaCres
86965.00 Isquare feet DA Area 2.00 acres
6701.00
square feet
1
46616.00
square feet
0.98
3634.00
square feet
0,95
3200.00
square feet
0.95
square feet
o.95
square feet
0-95
square feet
0.95
60151.00 square feet
0
SURFACE AREA CALCULATION (with added DA and BUA at different design storm)
Overall % Impervious
69.17%
SA/DA Ratio
6.92%
Average Design Depth
3.5
1
feet Req. SA
6015 sf
TSS, 85 or 90:
90
% Prov. SA
6823 sf
TEMPORARY POOL AND FOREBAY VOLUME CALCULATIONS
New BUA
Old BUA
Drainage Area®
86965.00
sf
BUA
60151.00
0.00
sf
Post development Rv=
0.673
#DIV/0!
unitless
Old BUA Design Storm
inches
Old BUA Design Volume
0
1.5" New BUA Design Storm Volume
7311
1 yr. 24 hour precipitation depth (inches)
3.70
from NOAA chart
Predevelopment Rv value
0.05
Use 0.05 if no existing BUA
1 yr. 24 hr. Pre -development volume
1341
cubic feet
1 yr. 24 hr. Post -development volume
18033
cubic feet
2008 Design Volume 16692 cubic feet
Phase 2 Design Volume
16692
cubic feet
Required Volume
16692
of
Area, sf
Inc. volume
Acc. volume
Top of Sediment
1.50
msl .........
658.00
0.00
0.00
Bottom of Sheff
6.50
msl..........
4683.00
13352.50
13352.50
Permanent Pool
7.00
msl.........
6823.00
2876.50
16229.00
Top of Shelf
7.50
msl..........
8872.00
3923.75
20152.75
Temporary Pool
8.94
IMS1.........
10954.00 1
13878.20
34030.95
Volume met at elev
9.29
msl
FOREBAY
Vol. Prov. at TP 17801,95
cf
Perm. Pool Volume=
16229
Req. Forebay Volume=
3246
Provided Volume=
Percent=
0.0%
Calculated Averacte Depth, feet
13.27
Max Pumo HP
NIA
ORIFICE CALCULATION
Average Head
Flow 02, cfs
Flow 05, cfs
No. of Orifices
Diameter, inches
Drawdown =
1 yr 24 hr intensity, in/hr
Runoff Coefficient
1 yr 24 hr peak Q
Orifice flow< 1yr24hr ?
feet Q2 Area = 3.71
cfs Q5 Area = 1 A8
cfs Orifice Area = 3.14
Avg. Flow Q= 0.082
or weir H x W in x
days '# of end contractions, N =
NOAA chart @t discharge coefficient, C =
unitiess Effective weir length, L
cfs
sq. inches
sq. inches
sq. inches
cfs
0.61
0.097
0,039
1
2.00
2.4
0.15
3.34
o.75
10.00
0.23
YES -OK