HomeMy WebLinkAbout20201005_A0009CFinalEA_DWRComments
North Carolina Department of Environmental Quality | Division of Water Resources
512 North Salisbury Street | 1617 Mail Service Center | Raleigh, North Carolina 27699-1617
919.707.9000
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
October 5, 2020
MEMORANDUM____________________________________________________
To: Lyn Hardison, Environmental Coordinator, Office of Legislative and Intergovernmental Affairs
Through: Amy Chapman
From: Kevin Mitchell, Division of Water Resources, Asheville Regional Office
Subject: Comments on the Environmental Assessment related to proposed improvements to Appalachian
Development Highway System Corridor K in Graham County, Federal Aid Project No. APD-
0074(178), STIP Project No. A-0009C.
This office has reviewed the referenced document dated August 26, 2020. The NC Division of Water Resources
(NCDWR) is responsible for the issuance of the Section 401 Water Quality Certification for activities that impact
Waters of the U.S., including wetlands. It is our understanding that the project as presented will result in impacts to
jurisdictional wetlands, streams, and other surface waters. The NCDWR offers the following comments based on
review of the aforementioned document:
Project Specific Comments:
1. This project is being planned as part of the 404/NEPA Merger Process. As a participating team member, the
NCDWR will continue to work with the team.
2. To meet the requirements of NCDOT’s NPDES permit NCS000250, the road design plans shall provide
treatment of the stormwater runoff through BMPs as detailed in the most recent version of the North Carolina
Department of Transportation Stormwater Post-Construction Stormwater Program Manual, and the Best
Management Practices Toolbox Manual. The BMPs should, to the MEP, be selected and designed to reduce
impacts of the target pollutants of concern (POCs) for the receiving waters.
3. Review of the project reveals the presence of surface waters classified as Water Supply Critical Area in the
project study area. Given the potential for impacts to these resources during the project implementation, the
NCDWR requests that the NCDOT strictly adhere to North Carolina regulations entitled Design Standards in
Sensitive Watersheds (15A NCAC 04B .0124) throughout design and construction of the project. This would
apply for any area that drains to streams having WS CA (Water Supply Critical Area) classifications.
4. Sweetwater, Tulula, and Stecoah Creeks are class Trout waters of the State. The NCDWR recommends that
the most protective sediment and erosion control BMPs be implemented to reduce the risk of turbidity
North Carolina Department of Environmental Quality | Division of Water Resources
512 North Salisbury Street | 1617 Mail Service Center | Raleigh, North Carolina 27699-1617
919.707.9000
violations in trout waters. In addition, all disturbances within trout buffers should be conducted in accordance
with NC Division of Land Resources and NC Wildlife Resources Commission requirements. Post-
construction stormwater BMPs should, to the MEP, be selected and designed to reduce TSS and avoid a
sustained increase in the receiving water temperature.
5. Prior to commencing ground disturbing activities, an acceptable monitoring and mitigation plan for the
presence of sulfide-bearing rock must be approved by the NCDWR.
General Comments:
1. The environmental document 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
2H.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. Environmental impact statement alternatives shall consider design criteria that reduce the impacts to streams
and wetlands from storm water runoff. To meet the requirements of NCDOT’s NPDES permit NCS000250
these alternatives should include road designs that allow for treatment of the storm water runoff through best
management practices as detailed in the most recent version of the North Carolina Department of
Transportation Stormwater Best Management Practices Toolbox manual, which includes BMPs such as
grassed swales, buffer areas, preformed scour holes, retention basins, etc.
3. After the selection of the preferred alternative and prior to an issuance of the 401 Water Quality Certification,
the NCDOT is respectfully reminded that they will need to demonstrate the avoidance and minimization of
impacts to wetlands (and streams) to the maximum extent practical. In accordance with the Environmental
Management Commission’s Rules (15A NCAC 2H.0506[h]), mitigation will be required for impacts of
greater than 0.1 acre to wetlands. In the event that 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 to assist with wetland mitigation.
4. 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 single stream. In the event that
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 to assist with stream mitigation.
5. Future documentation, including the 401 Water Quality Certification Application, shall continue to include an
itemized listing of the proposed wetland and stream impacts with corresponding mapping.
6. The NCDWR is very 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.
7. 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.
8. Where streams must be crossed, the NCDWR prefers bridges be used in lieu of culverts. However, we realize
that economic considerations often require the use of culverts. Please be advised that culverts should be
countersunk to allow unimpeded passage by fish and other aquatic organisms. Moreover, in areas where high
North Carolina Department of Environmental Quality | Division of Water Resources
512 North Salisbury Street | 1617 Mail Service Center | Raleigh, North Carolina 27699-1617
919.707.9000
quality wetlands or streams are impacted, a bridge may prove preferable. When applicable, the NCDOT
should not install the bridge bents in the creek, to the maximum extent practicable.
9. Whenever possible, the NCDWR prefers spanning structures. Spanning structures usually do not require work
within the stream or grubbing of the streambanks and do not require stream channel realignment. The
horizontal and vertical clearances provided by bridges shall allow for human and wildlife passage beneath the
structure. Fish passage and navigation by canoeists and boaters shall not be blocked. Bridge supports (bents)
should not be placed in the stream when possible.
10. 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. To meet the requirements of NCDOT’s NPDES permit NCS000250, please
refer to the most recent version of the North Carolina Department of Transportation Stormwater Best
Management Practices Toolbox manual for approved measures.
11. Sediment and erosion control measures should not be placed in wetlands or streams.
12. 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.
13. 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.
14. Based on the information presented in the document, the magnitude of impacts to wetlands and streams may
require an Individual Permit (IP) 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.
15. 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 NCG010000.
16. 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.
17. 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.
North Carolina Department of Environmental Quality | Division of Water Resources
512 North Salisbury Street | 1617 Mail Service Center | Raleigh, North Carolina 27699-1617
919.707.9000
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.
18. 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.
19. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved
under General 401 Certification Number 4132/Nationwide Permit No. 6 for Survey Activities.
20. 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.
21. 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.
22. While the use of National Wetland Inventory (NWI) maps, NC Coastal Region Evaluation of Wetland
Significance (NC-CREWS) maps and soil survey maps are useful tools, their inherent inaccuracies require
that qualified personnel perform onsite wetland delineations prior to permit approval.
23. 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.
24. 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.
25. 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.
The NCDWR appreciates the opportunity to provide comments on your project. Should you have any questions or
require any additional information, please contact Kevin Mitchell at (828) 296-4650 or kevin.mitchell@ncdenr.gov.
Electronic copy only distribution:
Crystal Amschler, US Army Corps of Engineers, Asheville Field Office
Chris Militscher, US Environmental Protection Agency
Aaron Williams, Federal Highway Administration
File Copy