SW6201101_trn_dlq_swm_letter_20201217_20201217

® Stantec
Stantec Consulting Services Inc.
801 Jones Franklin Road, Suite 300, Raleigh, NC 27606
December 17, 2020
File: 178451236: Military Working Dog — Stormwater Management Permit Submittal
N.C. DEQ Energy, Mineral and Land Resources — Stormwater Program
1612 Mail Service Center
Raleigh, N.C. 27699-1612
Attention: Mr. Corey Anen
Reference: Request for Additional Information Stormwater Permit No. SW6201101 Military Working
Dog Facility PN 752426 Cumberland County
Dear Mr. Anen,
Stantec is pleased to respond to your request for additional information dated December 7, 2020 for
the referenced stormwater permit application. Please find our responses to the request for additional
information in the pages following this cover letter.
Enclosed please find the following:
1. Two (2) copies of revised plans CG401, C504, C-509, SWM 102, and SWM 102
2. One (1) copy of the revised EZ supplemental form
4. One (1) copy of responses to request for additional information (included with cover letter)
Please let us know if you have any questions or need any additional information.
Sincerely,
STANTEC
Dan Saltsman, PE
Project Manager
Attachment: Enclosures

(3 Stantec
December 17, 2019
Responses to Request for Additional Information
Page 2 of 2
RESPONSES TO REQUEST FOR ADDITIONAL INFORMATION
1. Please provide a plan that clearly labels all BUA within the project area, including
the BUA that drains to the infiltration system, existing BUA, and offsite BUA. Based on
the drainage area plan (SWM 102), the BUA draining to the SCM appears to be much
lower than reported in the application, calculations, and Supplement EZ. The existing
BUA within the drainage area also appears to be larger than reported on the application
form (3,265 sf).
Response: SWM102 has been updated to better define the different BUA's.
2. According to the Supplement EZ, the infiltration basin does not treat the net increase
in BUA as required by 15A NCAC 02H .1003(3)(d). The form says that the new BUA on
the entire site is 61,544 sf as opposed to 44,391 sf treated by the infiltration basin.
Response: SWM102 has been updated to better define the different BUA's.
The infiltration basin currently treats 91,731 sf total impervious surface
comprised of off -site existing and new BUA.
3. The design volume reported in Field 2 of the infiltration basin Supplement EZ
sheet is less than the calculated minimum design volume (5,180 cf vs. 7,796 cf).
Response: The 5,810 cf was an older calculation that did not get updated
before the submittal. The correct design volume of the SCM is 8,650 cf.
4. Please provide a detail of the infiltration basin that meets the requirements of 15A
NCAC 02H .1042(2)(h).
Response: The infiltration basin detail (C8) has been revised with more
information per 15A NCAC on sheet C-504 of the plan set.
5. Please add a note that states that the infiltration will be cleaned out after
construction and converted to its approved design state [15A NCAC 02H .1050(7)].
Please also complete Field 10 of the infiltration basin Supplement EZ sheet.
Response: A note was added in the Construction Sequence on CG101 for the
contractor to clean out the SCM after construction. Field 10 on the Supplemental
EZ sheet was answered (YES).
6. Some of the runoff from the BUA is collected in catch basins and discharged directly
into the infiltration basin without pretreatment. Pretreatment is required for all runoff
discharged into an infiltration system [15A NCAC 02H .1051(4)].
Response: An 18" sump was added to manhole A3 (the last structure before
discharging into the infiltration basin), see sheet CG401 and C-509.