20080535 Ver 1_WRC Comments_20080404

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q North Carolina Wildlife Resources Commission 9
MEMORANDUM (? ??Q`fn?7? D
TO: Amanda Jones, USACOE I?
Asheville Regulatory Field Office APR 4 , 2008
FROM: Ron Linville Regional Coordinator / jER QUA?JT
AND ST13vwB
Habitat Conservation Program YanmDs DENR VW ER
DATE: March 27, 2008
SUBJECT: Landstar Development - Alpine Creek Subdivision, Cranberry Creek, Avery County
The applicant proposes to install multiple culverts to provide site 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 subdivide the property into 28 private lots. Four (4) culverts are indicated as necessary to access the
property and individual lots. Creek crossings are indicated for perennial streams ranging in size from 6-foot to 16-
foot in width. Total impacts are indicated to be 205 linear feet of channel. Total imperviousness is indicated as 4.6
percent. Wild Brown trout are known for Cranberry Creek.
Our application review led us to be concerned about culvert slope, design, and installation methods being used for
this project. No end views or plan views were providing showing the width of streams or any designs specifically
provided to ensure aquatic life passage and continued floodplain and stream functionality. No photographic site
details were provided. We are also concerned about the use of multiple barreled pipes placed on the same elevation,
the use of slick walled plastic pipes, and steep pipe slopes. These concerns were discussed with project engineers
and consultants on March 24, 2008.
Due to time constraints, a site visit was not done. Based on our review of the submittal and providing that aquatic
life passage is occurring now, we will not object to the project providing the following conditions are implemented:
1. In stream work and land disturbance within the 25-foot wide buffer zone should be prohibited during
the brown and brook trout spawning season of October 15 through April 15 to protect the egg and fry
stages of trout from off-site sedimentation during construction.
2. Bridges are recommended for all permanent crossings of streams, floodplains and associated wetlands
to eliminate fill in active streams and floodplains. Floodplain capacities and floodplain functions
should be maintained or restored. Where culverts must be used, culverts should be designed and
constructed to ensure passage of storm flow events and passage of aquatic organisms during low flow
conditions. 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 least a foot (12")
below the streambed. Culverts less than 48" diameter must be buried to a depth equal to or greater
Mailing Address: Division of Inland Fisheries • 1721 Mail Service Center • Raleigh, NC 27699-1721
Telephone: [phone] • Fax: [phone]
Landstar - Alpine Creek Subdivision Page 2
March 27, 2008
than twenty (20) percent of their diameter. Depth of burial must be based on the stream's natural
thalweg 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. Piping should be large enough to prevent
high velocity erosion (faucet effect) on the downstream end and erosive swirling on the upstream end.
Bottomless arch culverts should be large enough and installed in a manner that a) the active stream and
bank full benching can be accommodated within the structure and b) significant floodwaters can access
the floodplain without structural or riparian zone damage. Flat concrete aprons between wing-walls
must not be used. Riprap must not be placed in the streambed unless absolutely necessary and if used
in charnel, it must provide natural channel dimensions. If multiple barrels are installed, base flow
barrels 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 with a floor material
easily used by terrestrial wildlife. Plastic pipes should be corrugated (not smooth or slick) on the
inside so that bed load materials can be established to provide and maintain natural substrates.
3. Remaining jurisdictional waters and wetlands should be buffered, either through protection or
provision of undisturbed forested buffer zones. Buffers should be permanently preserved as common
contiguous forest areas instead of being subdivided into portions of individual lots. For streams that
do not support federally listed threatened or endangered aquatic species, we recommend 50'
intermittent and 100' perennial stream buffers. Maximum available buffers should be provided;
however, the twenty-five (25) foot trout buffer should remain undisturbed to the maximum extent
practicable. Community walking trails may be placed in the buffer zone providing they are kept away
from streams to the maximum extent practicable and the buffer widths do not exceed minimum width
requirements specified in the Americans with Disabilities Act (ADA).
4. Sediment and erosion control measures should adhere to the design standards for sensitive watersheds
(15A NCAC 413.0124).
5. If any concrete will be used, work must be accomplished so that wet concrete does not contact stream
water.
6. 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.
7. Temporary or permanent native herbaceous vegetation should be established on all bare soil within
five (5) days of ground disturbing activities in the twenty-five (25) foot trout buffer to provide long-
term erosion control. Disturbed streams should be planted with autochthonous (native) plants like
silky dogwood, rhododendron, dog hobble, red maple, silky willow, tag alder, black willow, sycamore,
river birch, or other native woody species. Natural fiber matting is recommended over plastic matting
that can impinge and entrap small animals.
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: Kevin Barnett, DWQ-ARO