Mitchell Community College Health Sciences Building - 6028-MCC-NCDEQ Storm Comments Response

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May 14, 2018

Corey Anen
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources
1612 Mail Service Center
Raleigh, North Carolina 27699

Project: Mitchell Community College Health Sciences Building
Permit No.: SW3180305
Designer: LandDesign
Contact: [e-mail]

Re: Responses to Request Additional Information – Stormwater Review

1. General MDC 9 requires all SCMs and associated maintenance accesses on privately owned land
except for those located on a single family residential lots to be located in permanent recoded
easements. Please revise the plan to show the easement and maintenance access.

RESPONSE: Maintenance access easement added. See sheet C4.00.

2. Sand filters with an open bottom require 2 feet of separation from the seasonal high water
table. The separation should be established with a hydrogeologic evaluation prepared by a
licensed professional. Please provide such an evaluation to demonstrate the location of the
seasonal high water table.

RESPONSE: Evaluation provided by ECS. Summary: existing ground surface is at 910 elev, the
study reported the SHWT is greater than 10 ft below ground surface. See report enclosed.

3. The sand filter must be designed so that the storage volume in both the sediment chamber and
sand chamber is equivalent.

RESPONSE: Sand filter has been updated. Refer to sheet C4.02 and the updated Supplement-
EZ form enclosed.

4. In accordance with Sand Filter MDCs 6 and 8, the sand media must meet ASTM C33 or
equivalent and must be maintained in a manner that results in a drawdown of at least two
inches per hour at the sand surface. Please add these specifications to the design plans.

RESPONSE: Note added. Refer to sheet C4.02.

5. 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: Revised PDFs have been uploaded. Hardcopies of revised plan sets and
corresponding forms have been mailed to 1612 Mail Service Center Raleigh, North Carolina
27699
Sincerely,
GRISELDA RUAN, EI
Designer | Charlotte | (o) 704.333.0325