19970722 Ver 1_More Info Letter_19980720 (2)

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
July 20, 1998
Andrea M. Spangler
Environmental and Special Projects Manager
Piedmont Triad Regional Water Authority
Wilmington Building, Suite 207
2216 West Meadowview Road
Greensboro, NC 27407-3480
Dr. Gerald McCrain
EcoScience Corporation
612 Wade Avenue
Raleigh, NC 27604
Re: Randleman Lake Compensatory Mitigation Proposal
Dear Ms. Spangler and Dr. McCrain:
Pete Colwell, Ron Linville, and I have reviewed the latest proposal submitted by
EcoScience for the wetland mitigation for the Randleman Lake project. The proposal
identifies 10 potential wetland mitigation sites, which are projected to yield 122 acres of
wetland restoration, or creation, which will satisfy the 1:1 wetland mitigation
requirement for the project. At six of the sites a total of 69 acres of wetlands are
proposed to be restored or created by the use of in-stream structures to put water back
onto existing floodplains. The remaining 4 sites will create wetlands through "green tree
impoundments" along the associated stream.
Generally, the Division feels that the proposed wetland mitigation sites are
worthy of further examination. Listed below are some of the concerns expressed during
our review.
1) Minimal release of water with the instream structures to maintain existing
uses in the streambed.
2) Design criteria that might allow for fish migration in the larger streams.
3) Maintenance and management of the water control structures, particularly
with the green tree impoundments.
4) Possible use of "forebays" to collect sediments and protect the wetland
mitigation sites downstream.
Environmental Sciences Branch 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
The Division also recommends that you calculate the watershed size that may be
treated with the wetland mitigation sites and provide any supporting documentation as to
the nutrient removal effectiveness of these areas for the overall watershed management
plan. We also encourage the Authority to identify some additional potential mitigation
sites should any of those proposed fail to produce the wetland acres estimated or are
simply not available for mitigation. Should you have any questions or wish to discuss
additional mitigation sites please contact Pete Colwell or myself at 919-733-1786.
Sincerely,
4Wtlands n R. D ey
/ 401 Gro
cc: Ed Powell, DMP
Ron Linville, DWQ Winston-Salem Regional Office
David Franklin, US Army Corps of Engineers
Pete Colwell, DWQ Central Office