SWA000034_CourtesyLetter_20180905

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
September 5, 2018
Mr. David E. Whittington, PE
SEPI Engineering
1025 Wade Avenue
Raleigh, NC 27605
Subject: Stormwater ATC Project No. SWA000034
Violet Solar Farm
Cabarrus County
Dear Mr. Whittington:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
TOBY VINSON
Interim Director
The Division of Energy, Mineral and Land Resources (DEMLR), received a State Stormwater Fast Track
Process: Authorization to Construct (ATC) Permit Application for the subject project on August 15, 2018.
Staff review for Fast Track Permitting usually involves only a cursory review to ensure that all required
documentation has been submitted for the Authorization to Construct Permit. A detailed review for
compliance with the stormwater regulations is performed before issuing the Final Permit. This letter is
being sent as a courtesy to make you aware that in reviewing the documents, I noted certain technical
deficiencies that would better be addressed before construction.
1) One of the ditches is shown as being lined with rip rap. The low density regulations at 15A
NCAC 02H .1003(c) require that stormwater that cannot be released as dispersed flow shall be
transported by vegetated conveyances.
2) The ditches are listed as having 2:1 side slopes. The low density regulations at 15A NCAC
02H .1003(c)i require all side slopes to be no steeper than 3:1 unless it is demonstrated that the
soils and vegetation will remain stable in perpetuity.
3) One of the ditches is shown as being lined with NAG S75. According to North American Green's
specifications online, this erosion control blanket is designed for short term applications with a
functional longevity of up to 12 months. The design permissible shear stress and velocity shown
in the specifications are also insufficient when compared to the calculated shear stress and
velocity.
The application for the ATC is complete and nothing further is required to be submitted. After
construction, the Division will review the as -built site design for compliance with the stormwater
regulations before issuing the Final Permit. I will be issuing the ATC permit shortly. If you have any
questions, please contact me at [phone] or [e-mail].
,S�inceerrely,
� �r,`i'"� a, -
cc: Melissa Parker, Project Manager — National Renewable Energy Corporation
State of North Carolina I Environmental Quality I Energy, Mineral and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9200 T