SW8020422_COMPLIANCE_20190103

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO. SWA�2a�1
DOC TYPE ❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
YV COMPLIANCE EVALUATION INSPECTION
DOC DATE-
YYYYMMDD

INFILTRATION BASIN ANALYSIS
FILENAME: G:IDATAIWPDATAIWQSIINBASIN1020422.WK1
PROJECT NUMBER: 020422
DATE: 19-Jan-03
PROJECT NAME: 128 S. Water Street Building
DRAINAGE BASIN: Cape Fear
REVIEWER: L. Lewis
RECEIVING STREAM: Cape Fear River
CLASS: SC
Index No.: 18-71
If ORW, is site within the 575' AEC?
SITE AREA: acres
DRAINAGE AREA: >:39QB' Sr -
IMPERVIOUS AREA CALCULATION
Rational C
BUILDINGS
3256 0.96
PARKING/ASPHALT
CONCRETE
OTHER
TOTAL
Place a "1" here if Rational _1
% IMPERVIOUS, 1= $3 3%
RV= .05+.009 ( I) _
,. .08
ELEVATION OF SEASONAL HIGH WATER TABLE
<„i<2 FEET MSL
REPORTED INFILTRATIOK'RATE
:.:..:..:..:..:..::..:.: INCHESIHOUR
c
or 0.000023 FPS
SURFACE AREAS AND ELEVATIONS
Elev. (ft) Area, sq ft
Inc. Volume Acc. Volume
BOTTOM 6 128.6
0
}
0 0
TOP 8.2 128.6
282.92 282.92 roof drain riser
top elevation
VOLUME 1 DEPTH 1 DRAWDOWN CALCULATION
DESIGN STORM, INCHES
.:.::::1
DESIGN VOLUME
2T1'
CUBIC FEET
70TAL VOLUME AVAILABLE
82,9Z
CUBIC FEET
DEPTH OF RUNOFF
FEET
TIME TO DRAWDOWN
::::>6d
HOURS MUST BE <120
25 YEAR 24 HOUR STORM NIA
Intensity, i = .33 inches 1 hour
Or-- C i A = '
nla CFS
Qp through the bottom of the basin=
s
nla CFS Must be > Qr
10 YEAR 10 MIN HIGH INTENSITY EVENT
Intensity, i = 6.3 inches 1 hour
Volume for 10 yr. 10 min. event =
nla CF < CF
COMMENTS
Volume and drawdown are (not) within Design Requirements.