20072096 Ver 1_WRC Comments_20080108

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~ North Carolina Wildlife Resources Commission ~
MEMORANDUM
TO: John Thomas, USACOE
Raleigh Regulatory Field Office
Cyndi Karoly, 401 Certification Unit
NC Division of Water Quality
Ron Linville Re Tonal Coordinator
FROM: ~ g
Habitat Conservation Program
DATE: January 4, 2008
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SUBJECT: Fearrington Forrest Subdivision, Tomahawk Creek, DWQ No. 20072096, Tomahawk
Creek, Forsyth County
The applicant proposes to install culverts to provide subdivision connectivity and access. 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 project will include installation of a 96' x 48 RCP and a dual 90' x 66 RCP. Both culverts will have
concrete headwalls. Total impacts to waters are indicated to be 230 linear feet, including riprap. The
Brook floater, Alasmidonta varicosa (NCE/FSC) is known downstream for the Yadkin River. Mussels
are dependent on mobile host species that disperse juveniles. Maintaining passage for host species
throughout headwaters and their tributaries is important.
Based on our review of the submittal, we will not object to the project as proposed providing the
following conditions are implemented:
1. Sediment and erosion control measures should adhere to the design standards for sensitive
watersheds (15A NCAC 4B .0124).
2. Appropriate mitigation should be provided, preferably within the sub basin where these
impacts occur.
3. 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.
Mailing Address: Division of lnland Fisheries 1.721 Mail Service Center Raleigh, N(: L ibyy-i i~~
Telephone: [phone] Fax: [phone]

• Fearrington Forrest -Page 2 - January 4, 2008
Fooodplain capacities and floodplain functions must be maintained with bridges and culverts. if
culverts must be used, culverts must be designed and constructed to ensure passage of aquatic
organisms. Culverts should be as short as possible. Culverts 48" diameter or larger must be
buried at least a foot (12") below the streambed. Culverts less than 48" diameter must be buried
to a depth equal to or greater than twenty (20) percent of their diameter. Depth of burial must be
based on the stream's .natural thalwea depth. 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. Ripran must not be placed
in the streambed unless absolutely necessary and if used in channel, it must provide natural
channel dimensions. If multiple barrels are needed, base flow barrel(s) must be installed as
indicated above while any additional barrel(s) should be placed with floors located at the active
floodplain or bank full elevation. These elevated barrels must 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 with a floor material easily used for terrestrial wildlife passage.
4. Work must be accomplished so that wet concrete does not contact stream water.
Heavy equipment should be operated from the bank rather than in the stream channel in order
to minimize sedimentation and reduce the likelihood of introducing other pollutants into the
stream. If equipment must be used in the channel, it should be new or clean, low-hour and
well maintained. Spill containment equipment should be readily available if equipment will
be used in the buffer and in the stream.
6. Due to listed species in the river basin, temporary or permanent herbaceous vegetation should
be planted on all bare soil within five (5) days of ground disturbing activities in the buffer
zone to provide long term erosion control. We encourage the use of native onsite vegetation
and materials for stream bank stabilization when practicable.
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