HomeMy WebLinkAbout20200579 Ver1_Whirligig SMP Approval Letter 06052020
June 5, 2020
DWR # 2020-0579v1
Wilson County
Noah Parsons, Stormwater Compliance Specialist
City of Wilson
Post Office Box 10
Wilson, North Carolina 27894-0010
Subject: APPROVAL OF SAND FILTER SCM TO GENERATE NUTRIENT OFFSET CREDITS
Whirligig Station Sand Filter System
Dear Mr. Parsons:
The Division of Water Resources (Division) recently received a Stormwater Management Plan (SMP) for
the Whirligig Station from McAdams Company on behalf of the City of Wilson. The proposed Stormwater
Control Measure (SCM) is a sand filter system that will be constructed by and for the City of Wilson with
the intent to generate nutrient load reductions for nutrient offset credits under 15A NCAC 02B .0703. The
design of the sand filter system and its associated nutrient reduction calculations were reviewed by the
Division for compliance with 15A NCAC 02H .1050 through .1062 and parts of 15A NCAC 02B .0703 (c-
d).
By copy of this letter, the Division hereby approves the SCM and authorizes that the proposed design for
the sand filter system meets the minimum design criteria as set out in 15A NCAC 02H .1050 and 1056.
Additionally, if designed, constructed and implemented in accordance with the SMP and supporting
documentation submitted to the Division, the project meets the nutrient offset credit approval standard
outlined in15A NCAC 02B .0703 (c). Any changes or modifications to the SCM may require additional
review and prior approval from the Division.
By copy of this letter, the Division also approves the applicant’s request to use the Neuse Method 2 Nutrient
Offset Calculations as the appropriate method to quantify the nitrogen nutrient offset credits that are
anticipated to be generated by this system. The calculations provided in the SMP estimate that the proposed
nutrient reduction project is likely to generate approximately 63.89 pounds (lbs.) of Nitrogen nutrient offset
credits per year if designed, constructed, implemented and sustained as proposed.
Additional project approval standards will be required if the City of Wilson decides to use the nutrient offset
credits from this nutrient reduction project as a Nutrient Offset Bank. Rule requirements for nutrient offset
banks and associated providers of the nutrient offset credits are defined more sp ecifically in 15A NCAC
02B .0703 (e-g). If you have any questions or concerns regarding nutrient offset banks, please contact Katie
Merritt at katie.merritt@ncdenr.gov.
DocuSign Envelope ID: D35A5166-5244-4F78-98AB-C06E79DAF832
DWR # 2020-0579v1
Page 2 of 2
If you have any questions or concerns regarding the SMP, please contact Chonticha McDaniel at
chonticha.mcdaniel@ncdenr.gov.
Sincerely,
Paul Wojoski, Supervisor
401 & Buffer Permitting Branch
cc: Rebecca Stubbs, PE – McAdams Company (via email)
Trish D'Arconte – DWR, Non-Point Source Planning Branch (via email)
Jim Hawhee – DWR, Non-Point Source Planning Branch (via email)
DWR 401 & Buffer Permitting Branch File
DocuSign Envelope ID: D35A5166-5244-4F78-98AB-C06E79DAF832