20240462 Ver 1_Polk County - B13 - NCWRC Comment Letter (10.31.23)_20240325

9 North Carolina Wildlife Resources Commission 9
Cameron Ingram, Executive Director
October 31, 2023
Patrick J. Breedlove
Division PDEA Engineer
N.C. Department of Transportation, Division 14
345 Toot Hollow Road
Bryson City, N.C. 28713
Subject Scoping Comments on Replacement of Bridge 13 over North Pacolet River on Howard
Gap Road (SR 1128), Polk County. BP14.R042.3
Dear Patrick,
The North Carolina Department of Transportation (NCDOT) invited comments from the North Carolina
Wildlife Resources Commission (NCWRC) on the subject bridge replacement. The project is being
developed as an emergency design -build. The NCWRC offers the following comments on the project to
conserve the affected wildlife resources and to promote wildlife -based recreation in accordance with the
applicable provisions of the state and federal Environmental Policy Acts (G.S. 113A-lthrough 113-10; 1
NCAC 25 and 42 U.S.C. 4332(2)(c), respectively), the Clean Water Act of 1977 (33 U.S.C. 466 et seq.)
and the Fish and Wildlife Coordination Act (48 Stat. 401, as amended; 16 U.S.C. 661-667d).
Standard Comments (NOTE specific recommendations follow these standard comments)
NCWRC standard recommendations for bridge and culvert replacement projects of this scope include:
1. New bridges or other channel spanning structures are recommended over culverts because they
typically require minimal if any stream impacts. The clearances of bridges allow for human access
and wildlife passage, fish passage, and navigation by boaters. Unlike bridges, culverts can prove
difficult to dewater during construction, which can lead to extended periods of channel instability and
erosion.
2. Bridge deck drains should not discharge directly into streams.
3. Live concrete should not be allowed to contact water in or discharge to streams
4. If possible, bridge supports (bents) should not be placed in stream channels.
Mailing Address: Habitat Conservation • 1721 Mail Service Center • Raleigh, NC 27699-1721
Telephone: [phone] • Fax: [phone]

BP14.R042.3 Page 2 October 31, 2023
Polk County
5. Applicable measures from the current NCDOT Erosion and Sediment Control Design and
Construction Manual should be implemented and maintained during construction. Matting used in
riparian areas should not contain nylon mesh because it entangles and kills wildlife. Coir matting
should be used on unstable stream banks that are steep or susceptible to high water and matting
should be securely anchored with wooden stakes according to NCDOT specifications.
6. Temporary detours and access roads should be designed and located to avoid wetland impacts, to
minimize clearing, and avoid destabilizing stream banks. Tree stumps and root mats should be left
where possible under and along temporary access roads to limit streambank disturbance and promote
regrowth of vegetation. Temporary fills should be removed to original ground elevations upon the
completion of the project. Disturbed areas should be seeded, or mulched, and native tree species
should be planted with a spacing of 10'x10'.
7. A clear strip of streambank (rip rap free) of 10 feet in width should remain on each side of the
channel underneath bridges to facilitate wildlife passage. Smaller widths are also beneficial where
there are narrow abutment setbacks. Alternatively, a "wildlife path" can be constructed with a top -
dressing of finer stone if full bank plating is required. These measures should also incorporate any
ditch line plating.
8. NCDOT biologists should be notified about streams that contain threatened or endangered species.
Special measures to protect these sensitive species may be required. NCDOT should also contact the
U.S. Fish and Wildlife Service for information on requirements of the Endangered Species Act as it
relates to the project.
9. All work in or adjacent to streams should be conducted in dry work areas. Sandbags, cofferdams, or
other clean diversion structures should be used where possible to avoid excavation in flowing water.
10. Heavy equipment should be operated from the banks rather than in stream channels to minimize
sedimentation and reduce the likelihood of introducing other pollutants into streams.
11. Only clean, sediment -free rock should be used as temporary fill (causeways) and fill material should
be removed with minimal disturbance of the natural stream bottom when construction is completed.
12. During geotechnical investigations, equipment should be inspected daily and maintained to prevent
contamination of surface waters from leaking fuels, lubricants, and hydraulic fluids.
The following recommendations apply to corrugated pipes, reinforced concrete pipes, or concrete box
culvert structures:
1. Culverts and pipes must be designed to allow for aquatic life passage in accordance with current
NCDOT Guidelines for Drainage Studies and Hydraulic Design. This typically includes burial of a
single low flow barrel at least 1 foot below the natural streambed and backfilling with native material.
If multiple barrels are required, then the high flow barrel(s) should be placed on or near a bankfull
elevation. These "flood" barrels should be reconnected to benches and include sills on the upstream
ends to restrict or divert base flow into the low barrel. Barrels with sills should be filled with
sediment to avoid standing water. If rip rap is used for backfilling, then it should also be topped with
native or other finer material to facilitate wildlife passage. In accordance with NCDOT Guidelines

BP 14.R042.3
Polk County
Page 3 October 31, 2023
for Drainage Studies and Hydraulic Design, alternating or notched baffles should typically be
installed in base flow culverts that are steep or longer than 40-50 linear feet in a manner that mimics
the existing stream flow pattern and profile.
2. Riprap should be minimized on banks and avoided on streambeds except where bed scour may be
expected. Rip rap placed on the streambed should be embedded or "keyed -in" to prevent or shorten
the duration of subsurface streamflow.
3. If multiple pipes or cells are used, then at least one pipe or box should be designed to remain dry
during normal flows to allow for wildlife passage.
4. Culverts or pipes should be aligned with the existing channel alignment whenever possible. Channel
widening should be avoided. Stream channel widening at the inlet or outlet end of structures typically
decreases water velocity, disrupts aquatic life passage, and causes sediment deposition that requires
increased maintenance.
Replacement of the existing bridge or culvert in the same location with road closure is typically
recommended to minimize impacts. If road closure is not feasible, then a temporary detour should be
designed and located to avoid wetland impacts, minimize the need for clearing, and avoid destabilizing
stream banks. If the structure will be on a new alignment, then the old structure and the approach fills
should be removed from the 100-year floodplain. Approach fills should be removed down to the natural
ground elevation. The area should be stabilized with grass and planted with native tree species. NCDOT
should restore the area to wetlands if the area reclaimed was previously wetlands.
Specific Comments
The North Pacolet River (C Tr) is trout habitat that supports naturally reproducing populations of Rainbow
Trout (Oncorynchus mykiss) in its upper reaches. The lower portion of this stream is sandy and trout
spawning likely does not occur near or downstream of the bridge. This project should not need to adhere to
the trout moratorium for any applicable permits.
While trout are not a concern, Broad River Spiny Crayfish (Cambarus spicatus, NC Threatened) are found in
the North Pacolet River and may be present at the bridge site. The NCWRC would appreciate being apprised
of the construction schedule, once known, so that the bridge area can be surveyed for these crayfish and any
animals moved, as needed. A notice a few weeks before construction, or an invitation to any preconstruction
meeting, is requested. My contact information can be used in any communication with construction staff
(e.g., green sheet commitments, contract notes).
Please contact me at david.mchenrya,ncwildlife.org or [phone] if you have any questions about
these comments. Thank you for the opportunity to review and comment on this project. The NCWRC
looks forward to assisting as needed as the project develops further.
Cordially,
Dave McHenry, NCWRC Western DOT Coordinator