SW6160401_20201228 SCM Supplement_Infiltration Basin_Rev.5_20201229

Permit No.
(to be provided by DWQ)
�OF WATFgo
��H -n r r
lei STORMWATER MANAGEMENT PERMIT APPLICATION FORM o
NCDENR 401 CERTIFICATION APPLICATION FORM
INFILTRATION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) 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, Resubmitted 12/28/2020
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 %
Design rainfall depth
1.80 in
Peak Flow Calculations
1-yr, 24-hr rainfall depth
1-yr, 24-hr intensity
Pre -development 1-yr, 24-hr discharge
Post -development 1-yr, 24-hr discharge
Pre/Post 1-yr, 24-hr peak flow control
Storage Volume: Non -SA Waters
Minimum design volume required
Design volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre -development 1-yr, 24-hr runoff volume
Post -development 1-yr, 24-hr runoff volume
Minimum required volume
Volume provided
Soils Report Summary
Soil type
Infiltration rate
SHWT elevation
Basin Design Parameters
Drawdown time
Basin side slopes
Basin bottom elevation
Storage elevation
Storage Surface Area
Top elevation
Basin Bottom Dimensions
Basin length
Basin width
Bottom Surface Area
s. iu in
0.13 in/hr
31.83 ft3/sec
8.68 ft3/sec
-23.15 ft3/sec
11,334.00 ft3
18,128.00 ft3 OK for non -SA waters
ft3
ft3
ft3
ft3
ft3
HSG "A"
7.50 in/hr
255.00 fmsl
0.10
days OK
N/A
:1 OK
267.00
fmsl OK
269.33
fmsl
10,800.00
ftZ
269.53
fmsl
180.00 ft
60.00 ft
10,800.00 ftZ
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 1 of 3

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-i n
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
Manufactured Treatment Device
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 2 of 3

Permit No.
(to be provided by DWQ)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
NTJ Ex. Permit
1. Plans (1" 50' or larger) of the entire site showing:
Design at ultimate build -out,
Off -site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
NTJ Ex. Permit
2. Partial plan (1" = 30' or larger) and details for the infiltration basin showing:
Bypass structure,
Maintenance access,
Basin bottom dimensions,
Basin cross-section with benchmark for sediment cleanout,
Flow distribution detail for inflow,
Vegetated filter, and
Pretreatment device.
NTJ Ex. Permit
3. Section view of the infiltration basin (1" = 20' or larger) showing:
Pretreatment and treatment areas, and
Inlet and outlet structures.
NTJ Ex. Permit
4. A table of elevations, areas, incremental volumes & accumulated volumes to verify the volume provided.
NTJ Ex. Permit
5. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. The
results of the soils report must be verified in the field by DWQ, by completing & submitting the soils
investigation request form. County soil maps are not an acceptable source of soils information.
NTJ CG501
6. A construction sequence that shows how the infitlration basin will be protected from sediment until the
entire drainage area is stabilized.
NTJ Narrative
7. The supporting calculations.
NTJ Narrative
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
N/A N/A
9. A copy of the deed restrictions (if required).
Form SW401-Infiltration Basin-Rev.4 Page 3 of 3 Part III. Required Items Checklist, Page 3 of 3