20000250 Ver 1_More Info Letter_20010409

QF W ATFR Michael F. Easley
~O~ QG Governor
Cp ~ William G. Ross, Jr., Secretary
1 ` ~ Department of Environment and Natural Resources
O ~ `C Kerr T. Stevens
~~ Division of Water oualiry
April 9, 2001
Mr. Carlton Burton, PE
Burton Engineering
5970 Fairview Road, Suite 100
Charlotte, NC 28210
Subject: Shopton Road Industrial Park
DWO Project No. 000250
Mecklenburg County
Dear Mr. Burton:
The Wetlands Unit staff reviewed the stormwater management plans for the subject project and determined that additional
information is necessary to complete the technical review process. The required additional information is as follows:
State stormwater Permit Application Fee
A State stormwater Permit is not required for this project at this time. Therefore, the application fee is being
returned with this correspondence.
2. Draw Down Orifice Outlet
Please provide detail showing the draw down orifice on the outlet detail.
3. Trash Guard
Unprotected weir structures will experience clogging problems and increase the maintenance effort required to keep
the basin functioning properly. The Division recommends that a trash guard be fitted on weir structures to prevent
floating debris from interfering with performance.
4. Forebay and Inlet/Outlet Structure Location
The combined volume at normal pool of the remote forebay and the other forebay should be approximately 20% of
the overall normal pool volume of the entire stormwater pond including the forebays. Each forebay should be sized
proportionally for the area tributary to each. Also, the Division recommends that 3:1 side slopes be used for the
remote forebay. If 2:1 side slopes are to be used, the side slopes must be stabilized with erosion control matting or
similar erosion prevention measures. Please revise plans to show the above.
More importantly, the submitted remote forebay design will be subject to short circuiting. This issue may be
addressed through structure relocation, etc. Reference NCDENR stormwater Best Management Practices Manual,
April 1999. Please revise the engineering plans to meet this requirement.
5. Emergency Drain
An emergency drain must be provided to draw down the permanent pool volume in 24 hours or less. Reference
NCDENR stormwater Best Management Practices Manual, April 1999. Please specify this on the engineering
plans and supply calculations.
Division wetlands unit staff will strive to complete a final technical review within 10 working days of receipt of the
requested information. If you have any questions or would like to discuss this project, please contact me at (919) 733-
9584. Also, please note that the NCDENR stormwater Best Management Practices Manual, April 1999, and other
North Carolina Division of Water Quality, 401 Wetlands Certification Unit,
1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address)
2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location)
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documents and information can be downloaded from the Wetlands Unit web site at
http://h2o.ehnr.state.nc.us/ncwetlands/.
Sincerely,
~~~
Todd St. Joh , PE
Environmental Engineer
cc: John Dorney, Wetlands/401 Unit
Mooresville Regional Office
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