SW8060703_COMPLIANCE_20061003

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW qZl'&97o 3
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
INCOMPLIANCE EVALUATION INSPECTION
L
DOC DATE
YYYYMMDD

INFILTRATION TRENCH ANALYSIS
Filename: S:IWPDATAIWQSIINTRENCH1060703
Project# SW8 060703
Project Name Flywheel Office Park
Recvng Stream Bradley Creek
Drainage Basin Cape Fear
Site Area 3.06 acres
Impervious Area Calculation
Buildings
Streets/pkg
OS SW
Offsite
Total
Volume/Storage Calculation
26000
45507
6101
0
77608
If Rational Method is used, place a 1 in this box 0
Required
Provided
Design Storm
RV
Volume to Store
Pipe Diameter (equivalent)
Length Of a Single run of Pipe
Number of Pipe Runs in Trench
Storage In Piping
Total Storage in Piping
Date
03-Oct-06
Reviewer
P.Bartlett
Classification
SC; HQW
Index #
18-87-24-4-(1)
Drainage Area
133,294ISF
3.06 JAcres
Rational Cc (list C after each BUA)
1
1
1
1
% Impervious:
Cc: 0.67
1 lin
0.57
6376 CF
Pipe Size 1
Pipe Size 2
4.4
53
6447
0
58.2%
Feet
Feet
each
Cubic Feet
Cubic Feet
Cross -Sectional Area Of Pipe Runs 121.642 0.000 SF
Length Of Trench
Width Of Trench
Height Of Trench
Cross -Sectional Area Of Trench
Voids Volume, 40%
Total Voids Volume
Total Volume Provided
Feet
Feet
Feet
SF
CF
CF
Cubic Feet
(StormChamber: 15.17 cf/ft * 56 units * 7.587unit = 6,440 cf)
Elevation Of Bottom Of Trench 22.5 Mean Sea Level
Elevation Of SHWT 20.5 Mean Sea Level
Overflow Elevation 25.8 Mean Sea Level
Exfiltration Rate / Drawdown
Reported Hydraulic Conductivity
Bottom Surface Area
Drawdown Time
25 YEAR 24 HOUR STORM N/A
Intensity, i = .33 inches / hour
Qr=CiA=
Qp through the bottom of the basin=
10 YEAR 10 MIN HIGH INTENSITY EVENT
Intensity, i = 6.3 inches / hour
Volume for 10 yr. 10 min. event =
53
48
3.3
158.40
0.00
779
0
779
7226
0.67 CFS
1.3660 CFS
7701:03 CF <
1.9331 Cubic Feet Per Hour Per Sq Ft
2544.0 Square Feet
1.30 1 hours
Must be > Qr
7226 CF