SW4191202_Matcor - Response to Request for Additional Information - 1st Submittal_1/20/2020

Triad Design Group Response to Request for Additional Information
Date: January 17, 2020
To: Corey Anen
From: L. Allan Hill
Subject: Matcor Metal Fabrication Site Improvements - 1st Submittal
Stormwater Permit No. SW4191202
1. When the applicant is a corporation, documentation from the NC Secretary of State or
other official documentation showing the titles and positions held by the person who
signed the application is required [15A NCAC 02H .1042(2)(b)(ii)]. Because the
individual who signed the application (Tony Coomer) is not listed as an officer of the
corporation by the NC Secretary of State, additional documentation is required to show
that the individual has the authority to apply for the permit on behalf of the corporation.
This can be done by submitting a signed letter from one of the individuals listed by the
NC Secretary of State's website or other official documentation from the corporation.
I have attached a letter from Andrew McGillis giving Tony Coomer permission to act on Matcor's behalf for items
relating to the stormwater permit.
2. Please provide stage storage data for both the forebay and main pool individually to
verify that the volumes used in the calculations are correct.
TDG has provided stage -storage data for both the forebay and main pool in the revised calculations.
3. Please provide a detail of the outlet control structure for the wet pond.
The outlet control structure (riser/barrel) is located on sheet C1.8 right center of the sheet.
4. The wet pond detail on Sheet C1.8 and the Supplement EZ form say that the slope of the
vegetated shelf is 10H:1 V. However, the elevation change shown is 1' over a 6' wide
vegetated shelf. Note that in accordance with Wet Pond MDC 6 the vegetated shelf can
have a maximum slope of 6H:1 V.
TDG has corrected all plans and documents to agree. The proposed vegetated shelf is to be 6' wide with a 6H:1V
slope.
5. Please provide calculations showing that all inlets and outlets are designed with sufficient
outlet protection to prevent erosion during the peak flow from the 10-year storm (General
MDC 4).
TDG has provided calculations for the energy dissipator for the 18" RCP inlet into the pond. The pond outlet ties
directly into a proposed storm drain system so an energy dissipator is not required.
6. On the Drainage Areas sheet of the Supplement EZ form, please complete both columns.
The first should cover the entire project area and the second should cover only the
drainage area to the wet pond. Also on this sheet, for the design volume of the SCM,
please enter the minimum calculated treatment volume based on runoff from the 1"
storm.
TDG has completed both columns on the Drainage Areas Sheet. We changed the SCM design volume to the
minimum calculated treatment volume based on runoff from the 1" storm.
7. 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:Hedocs.deq.nc.gov/Forms/SW—Project—Submittal