SW6190503_2017.0643 Stormwater Round 2 CRL_7/25/2019

INTERPLANJ
Over 40 years and 40,000 projects
July 24, 2019
Corey Anen
North Carolina Department of Environmental Quality- DEMLR
512 North Salisbury Street -1612 Mail Service Center
Raleigh, NC 27699-1612
919.707.3649
[e-mail]
Reference: KinderCare Learning Center - Spout Springs
Stormwater Permit # SW6190503
I P # 2017.0643
Response to: Request for Additional Information
Dear Mr. Anen,
Please accept the following in response to comments dated July 16, 2019:
604 COURTLAND STREET
SUITE 1DO
ORLANDO, FL 32804
ph: 407,645.5008
fx: 407.629.9124
AA 003420 1 CA 8660
www.interplantic.com
1. Comment: The infiltration basin must have sufficient volume below the first outlet to
store the water quality design volume. The outlet should be elevated to
provide the required volume in the basin. (General MDC 1)
Response: Page 5 of Appendix E of the previously submitted stormwater report
summarizes the total system storage in the infiltration basin and
underground storage. The total system capacity below the water quality
orifice is 3,183 cf; which exceeds the required water quality volume of
3,139 cf.
Only the bottom area of the infiltration basin is used to calculate the
recovery time. Full water quality and infiltration calculations are provided
in Appendix F of the previously submitted stormwater report.
2. Comment: Please submit a signed and notarized operation and maintenance plan
and agreement for the infiltration system. (General MDCs 1 1 and 12).
Response: A notarized O&M plan and agreement for the infiltration system are
included with this submittal.
ORLANDO CHICAGO DALLA5IFOAT WORTH
ARCHITECTURE ENGINEERING INTERIOR DESIGN PERMITTING
PHILADELPHIA MIAMI
PERMITTING ENTITLEMENTS DUE DILIGENCE

INTERPLAW,
KinderCare Learning Center - Spout Springs
July 24, 2019
Page 2 of 2
3. Comment: The easement for inspection and maintenance access must include the
SCM. (General MDC 9)
Response: The access and maintenance easement on Sheet C1 is revised to include
the entire infiltration basin in addition to the 10' access berm.
4. Comment: On the Supplement Form:
a) The design storm was indicated as 6 inches rather than 1 inch. (Row 18)
b) The design volume for the SCM does not reflect the actual provided
volume in the calculations. (Row 18)
c) The calculation method should reflect the method for calculating the
design runoff volume (i.e., Simple Method or Discrete NRCS Method). (Row
19)
Response: The Supplement Form is revised as requested. The SCM design volume is
listed as the provided water quality volume from the previously submitted
stormwater report.
5. Comment: Drainage structure 17 on Sheet C3.1 should be lowered to be even with
the ground elevation to prevent standing water.
Response: Drainage Structure 17 is revised to be even with the bottom of the swale as
requested.
6. Comment: Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, and 1
hardcopy of other documents. Pdfs must be uploaded using the form at:
https://edocs.deq.nc.gov/Forms/SW Project Submittal
Response: Acknowledged, pdfs have been uploaded and 2 hardcopies are
provided.
Please feel free to contact me if you have any questions or require additional information. If I
am not available, George Georgy is the Project Manager and will be able to answer your
questions.
Sincerely,
INTERPLAN LLC
Stuart Anderson, PE, LEED AP
Director of Civil Engineering