20100294 Ver 1_WRC Comments_20100430

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?ecvd I North Carolina Wildlife Resources Commission 9

Gordon Myers, Executive Director
MEMORANDUM
TO: Monte Matthews, USACOE
Raleigh Regulatory Field Office
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FROM: Ron Linville, Regional Coordinator L9
Habitat Conservation Program
DATE: April 22, 2010 APg 3 C. 2?t0
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SUBJECT: Town of Wilkesboro, Tucker Hole Creek, Wilkes County
The Town of Wilkesboro proposes to install a culvert for access to a sewer line. Biologists with
the North Carolina Wildlife Resources Commission are familiar with habitat values in the area.
These comments are provided in accordance with the provisions of the Fish and Wildlife
Coordination Act (48 Stat. 401, as amended; 16 U.S.C. 661-667d) and the North Carolina
Environmental Policy Act (G.S. 113A-1 through 113A-10; NCAC 25).
The Town proposes to install a triple barrel culvert with each barrel being 60" diameter on a
perennial stream. The crossing is necessary to perform required inspection and maintenance
along the sewer line. Our review of the project area did not find any listed species. Streams in
this area support warm water fisheries and provide nursery habitats for the Yadkin River.
Accordingly, maintaining aquatic life passage is important.
Based on our review of the submittal and our knowledge of area habitats, we will not object to
issuance of Clean Water Act Section 404 Permits and/or Section 401 Certifications. The culvert
should be installed in a manner that does not impede aquatic life passage during low flow
conditions. We routinely recommend the following for culverts:
Bridges are recommended for all permanent roadway crossings of streams, floodplains and
associated wetlands to eliminate the need to fill and culvert active streams and floodplains.
Floodplain capacities and floodplain functions must be maintained with bridges and culverts. If
culverts must be used, culverts should be designed and constructed to ensure passage of aquatic
organisms. Culverts should be as short as possible and culverts should not be used for non
essential or non linear crossing purposes. Culverts 48" diameter or larger should be buried at
Mailing Address: Division of Inland Fisheries - 1721 Mail Service Center - Raleigh, NC 27699-1721
Telephone: [phone] - Fax: [phone]
Town of Wilkesboro Sewer Culvert Page 2 April 22, 2010
least a foot (12") below the streambed. Culverts less than 48" diameter should be buried to a
depth equal to or greater than twenty (20) percent of their diameter. Location and depth of burial
should be based on the stream's natural thalweg depth and thalweg location. Culverts should be
aligned and situated so that no channel realignment or widening is required unless such
modification will improve natural conditions. Widening of the stream channel at the inlet or
outlet of the culvert structure causes a decrease in water depth and velocity causing
sedimentation impacts and reduction of aquatic passage. Flat concrete aprons between wing-
walls must not be used. Riprap should not be placed in the streambed unless absolutely
necessary and if used in channel, riprap should provide natural channel dimensions. If multiple
barrels are needed, a base flow barrel(s) should be installed as indicated above while additional
barrels should be placed with floors located at the active floodplain or bank full elevation. These
elevated barrels should be connected to the active floodplain or bank full benches to ensure
natural stream dimensions for the base flow channel with sufficient water depth during low flows
and drought conditions to accommodate normally anticipated aquatic movement. If culverts are
long and/or sufficient slopes exist, alternating baffles should be provided in the base flow barrel
in a manner to conform to channel bends upstream and downstream, to mimic natural meanders,
to prevent upstream scour and downstream deposition, to move and contain typical bed load
materials, and to provide resting areas for aquatic species. When multiple barrels are used, at
least one barrel should be designed and constructed on a higher level with a floor material easily
used for terrestrial wildlife passage.
Thank you for the opportunity to review and comment on this project during the early planning
stages. If you have any questions regarding these comments, please contact me at 336-769-9453.
E-copy: Sue Homewood, DWQ-WSRO