HomeMy WebLinkAboutBridge 87 Watauga Co_DWR_CommentsROY COOPER
Governor
DIONNE DELLFGATTI
Secretary
S. DANIEL SMITH
Director
MEMORANDUM
NORTH CAROLINA
Environmental Quality
March 26, 2021
To: Luke Heavner (TGS Engineers) for NCDOT Division 11 (lheavner@tgsengineers.com)
DS
From: Dave Wanucha, NC Division of Water Resources, Winston Salem Regional Offic �g�lJ 3/26/2021
Subject: Scoping comments on proposed Bridge 87 replacement on SR 1227 (North Fork Road) over North Fork
Cove Creek in Watauga County. WBS No. BPI I.R002.
Reference your correspondence dated March 19, 2021 in which you requested comments for the referenced project.
Preliminary analysis of the projects reveals the potential for multiple impacts to streams and jurisdictional wetlands
in the project areas. More specifically, impacts to:
North Fork Cove Creek; Classification C; Index No. 8-15-2; Watauga River Basin, WAT01 (04-02-01).
Further investigations at a higher resolution should be undertaken to verify the presence of other streams and/or
jurisdictional wetlands in the area. If any jurisdictional areas are identified, the Division of Water Resources
requests that NCDOT consider the following environmental issues for the proposed projects:
General Project Comments:
1. Further environmental assessments should provide a detailed and itemized presentation of the proposed
impacts to wetlands and streams with corresponding mapping. If mitigation is necessary as required by 15A
NCAC 211.0506(h), it is preferable to present a conceptual (if not finalized) mitigation plan with the
environmental documentation. Appropriate mitigation plans will be required prior to issuance of a 401 Water
Quality Certification.
2. In accordance with the Environmental Management Commission's Rules (15A NCAC 2H.0506[h]),
mitigation will be required for impacts of greater than 300 linear feet to any perennial stream. If mitigation is
required, the mitigation plan shall be designed to replace appropriate lost functions and values. The North
Carolina Division of Mitigation Services may be available for assistance with stream mitigation.
3. The NCDWR is concerned with sediment and erosion impacts that could result from this project. The
NCDOT shall address these concerns by describing the potential impacts that may occur to the aquatic
environments and any mitigating factors that would reduce the impacts.
4. The NCDOT is respectfully reminded that all impacts, including but not limited to, bridging, fill, excavation
and clearing, and rip rap to jurisdictional wetlands, streams, and riparian buffers need to be included in the
final impact calculations. These impacts, in addition to any construction impacts, temporary or otherwise,
also need to be included as part of the 401 Water Quality Certification Application.
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512 North Salisbury Street 1 1617 Mail Service Center I Raleigh, North Carolina 27699-1617
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5. Bridge deck drains shall not discharge directly into the stream. Stormwater shall be directed across the bridge
and pre-treated through site -appropriate means (grassed swales, pre -formed scour holes, vegetated buffers, etc.)
before entering the stream. Please refer to the most recent version of the North Carolina Department of
Transportation Stormwater Best Management Practices Toolbox manual for approved measures.
6. Sediment and erosion control measures should not be placed in wetlands or streams.
7. Borrow/waste areas should avoid wetlands to the maximum extent practical. Impacts to wetlands in
borrow/waste areas will need to be presented in the 401 Water Quality Certification and could precipitate
compensatory mitigation.
8. The 401 Water Quality Certification application will need to specifically address the proposed methods for
stormwater management. More specifically, stormwater shall not be permitted to discharge directly into
streams or surface waters.
Based on the information presented in the document, the magnitude of impacts to wetlands and streams may
require a Nationwide (NW) permit application to the Corps of Engineers and corresponding 401 Water
Quality Certification. Please be advised that a 401 Water Quality Certification requires satisfactory protection
of water quality to ensure that water quality standards are met, and no wetland or stream uses are lost. Final
permit authorization will require the submittal of a formal application by the NCDOT and written concurrence
from the NCDWR. Please be aware that any approval will be contingent on appropriate avoidance and
minimization of wetland and stream impacts to the maximum extent practical, the development of an
acceptable stormwater management plan, and the inclusion of appropriate mitigation plans where appropriate.
10. If concrete is used during construction, a dry work area shall be maintained to prevent direct contact between
curing concrete and stream water. Water that inadvertently contacts uncured concrete shall not be discharged
to surface waters due to the potential for elevated pH and possible aquatic life and fish kills. Concrete shall
be handled in accordance with the NPDES Construction General Permit NCGO 10000.
11. If temporary access roads or detours are constructed, the site shall be graded to its preconstruction contours
and elevations. Disturbed areas shall be seeded or mulched to stabilize the soil and appropriate native woody
species shall be planted. When using temporary structures, the area shall be cleared but not grubbed.
Clearing the area with chain saws, mowers, bush -hogs, or other mechanized equipment and leaving the
stumps and root mat intact allows the area to re -vegetate naturally and minimizes soil disturbance.
12. Unless otherwise authorized, placement of culverts and other structures in waters and streams shall be placed
below the elevation of the streambed by one foot for all culverts with a diameter greater than 48 inches, and
20 percent of the culvert diameter for culverts having a diameter less than 48 inches, to allow low flow
passage of water and aquatic life. Design and placement of culverts and other structures including temporary
erosion control measures shall not be conducted in a manner that may result in dis-equilibrium of wetlands or
streambeds or banks, adjacent to or upstream and downstream of the above structures. The applicant is
required to provide evidence that the equilibrium is being maintained if requested in writing by the NCDWR.
If this condition is unable to be met due to bedrock or other limiting features encountered during construction,
please contact the NCDWR for guidance on how to proceed and to determine whether or not a permit
modification will be required.
13. If multiple pipes or barrels are required, they shall be designed to mimic natural stream cross section as
closely as possible including pipes or barrels at flood plain elevation, floodplain benches, and/or sills may be
required where appropriate. Widening the stream channel should be avoided. Stream channel widening at the
inlet or outlet end of structures typically decreases water velocity causing sediment deposition that requires
increased maintenance and disrupts aquatic life passage.
14. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved
under General 401 Certification Number 4085/Nationwide Permit No. 6 for Survey Activities.
15. Sediment and erosion control measures sufficient to protect water resources must be implemented and
maintained in accordance with the most recent version of North Carolina Sediment and Erosion Control
Planning and Design Manual and the most recent version of NCS000250.
16. All work in or adjacent to stream waters shall be conducted in a dry work area. Approved BMP measures
from the most current version of the NCDOT Construction and Maintenance Activities manual such as
sandbags, rock berms, cofferdams and other diversion structures shall be used to prevent excavation in
flowing water.
17. Heavy equipment should be operated from the bank rather than in stream channels in order to minimize
sedimentation and reduce the likelihood of introducing other pollutants into streams. This equipment shall be
inspected daily and maintained to prevent contamination of surface waters from leaking fuels, lubricants,
hydraulic fluids, or other toxic materials.
18. Riprap shall not be placed in the active thalweg channel or placed in the streambed in a manner that precludes
aquatic life passage. Bioengineering boulders or structures should be properly designed, sized and installed.
19. Riparian vegetation (native trees and shrubs) shall be preserved to the maximum extent possible. Riparian
vegetation must be reestablished within the construction limits of the project by the end of the growing season
following completion of construction.
Thank you for requesting our input at this time. The NCDOT is reminded that issuance of a 401 Water Quality
Certification requires that appropriate measures be instituted to ensure that water quality standards are met and
designated uses are not degraded or lost. If you have any questions or require additional information, please contact
Dave Wanucha at (336) 403-5655 or Dave.Wanucha@ncdenr.gov.
Electronic copy only distribution:
Kevin Hining, NCDOT, Division 11 DEO
Lori Beckwith, USACE, Asheville Office
Stacy Oberhausen, PE, TGS Engineers (soberhousen@tgsengineers.com)
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