SW6160401_Supplement_Infiltration Basin Part I and II 200902_20201002

Permit No.
(to be provided by DWQ)
o�OF WATE9oc
A70A� STORMWATER MANAGEMENT PERMIT APPLICATION FORM o 7
NCDENR 401 CERTIFICATION APPLICATION FORM
INFILTRATION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project Name USAJFKSWCS D-Area Campus Regional Stormwater System
Contact Person Lewis Hutchins
Phone Number 7579617750
Date 7/28/2020
Drainage Area Number As identified on plans
II. DESIGN INFORMATION
Site Characteristics
Drainage area
839,375.00 ftZ
Impervious area
477,853.00 ftZ
Percent impervious
56.93 0
Design rainfall depth
1.80 in
Peak Flow Calculations
1-yr, 24-hr rainfall depth
3.10
in
1-yr, 24-hr intensity
0.13
in/hr
Pre -development 1-yr, 24-hr discharge
31.83
ft3/sec
Post -development 1-yr, 24-hr discharge
8.68
ft3/sec
Pre/Post 1-yr, 24-hr peak flow control
-23.15
—ft'/sec
Storage Volume: Non -SA Waters
Minimum design volume required
11,334.00
ft3
Design volume provided
18,128.00
ft3
Storage Volume: SA Waters
1.5" runoff volume
ft3
Pre -development 1-yr, 24-hr runoff volume
ft3
Post -development 1-yr, 24-hr runoff volume
ft3
Minimum required volume
ft3
Volume provided
ft3
Soils Report Summary
Soil type
HSG "A"
Infiltration rate
7.50
in/hr
SHWT elevation
255.00
fmsl
Basin Design Parameters
Drawdown time
0.10
days
Basin side slopes
N/A
:1
Basin bottom elevation
267.00
fmsl
Storage elevation
269.33
fmsl
Storage Surface Area
10,800.00
ftZ
Top elevation
269.53
fmsl
Basin Bottom Dimensions
Basin length
180.00
ft
Basin width
60.00
ft
Bottom Surface Area
10,800.00
ftZ
OK for non -SA waters
OK
OK
OK
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 1 of 2

Permit No
(to be provided by DWQ)
Additional Information
Maximum runoff to each inlet to the basin?
Length of vegetative filter for overflow
Distance to structure
Distance from surface waters
Distance from water supply well(s)
Separation from impervious soil layer
Naturally occuring soil above shwt
Bottom covered with 4-in of clean sand?
Proposed drainage easement provided?
Capures all runoff at ultimate build -out?
Bypass provided for larger storms?
Pretreatment device provided
ac-in
N/A
ft
OK
16.00
ft
OK
600.00
ft
OK
>1000
ft
OK
25.00
ft
OK
25.00
ft
OK
Y
(Y or N)
OK
Y
(Y or N)
OK
Y
(Y or N)
OK
Y
(Y or N)
OK
Skimmer basins
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 2 of 2