HomeMy WebLinkAboutM-0540A Shoreline stabilizationROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
MEMORANDUM
NORTH CAROUNA
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January 28, 2021
To: Colin Mellor, NCDOT Environmental Policy Unit
From: Joanne Steenhuis, NC Division of Water Resources, Wilmington Regional Office"�� �Z vvytrLGC�
Subject: Scoping comments on proposed repair of the roadway embankment/causeway along NC 24 in Onslow and
Carteret Counties, State Project No. M-05430A.
Reference your correspondence dated January 5, 2021 in which you requested comments for the referenced project.
Preliminary analysis of the project reveals the potential for multiple impacts to streams and jurisdictional wetlands
in the project area. More specifically, impacts to:
Stream Name
River Basin
Stream Classification(s)
Stream Index
Number
303(d) Listing
White Oak River
White Oak
SA;H W
20- 18 / 20- 18 d
N/A
White Oak River
White Oak
SA;H W
20- 18 /20- 18 e2
N/A
White Oak River
White Oak
SA;H W
20- 18 /20- 18 c7
N/A
Further investigations at a higher resolution should be undertaken to verify the presence of other streams and/or
jurisdictional wetlands in the area. In the event that any jurisdictional areas are identified, the Division of Water
Resources requests that NCDOT consider the following environmental issues for the proposed project:
Project Specific Comments:
1. Review of the project reveals the presence of surface waters classified as SA;HQW High Quality Waters of the
State in the project study area. This is one of the highest classifications for water quality.
General Project Comments:
2. 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.
4.er� I D—W QW �� �
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000
3. Environmental impact statement alternatives shall consider design criteria that reduce the impacts to streams
and wetlands from storm water runoff. These alternatives shall include road designs that allow for treatment of
the storm water runoff through BMPs as detailed in the most recent version of the North Carolina Department
of Transportation Stormwater Best Management Practices Tool box manual, such as grassed swales, buffer
areas, preformed scour holes, retention basins, etc.
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 1 acre to wetlands. In the event that mitigation is required, the mitigation plan shall be designed to replace
appropriate lost functions and values. North Carolina Division of Mitigation Services may be available for
assistance with wetland mitigation.
5. 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. 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 for assistance with stream mitigation.
6. 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.
7. 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.
8. An analysis of cumulative and secondary impacts anticipated as a result of this project is required. The type and
detail of analysis shall conform to the NC Division of Water Resource Policy on the assessment of secondary
and cumulative impacts dated April 10, 2004.
9. 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.
i o. 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
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.
11. 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.
12. 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.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000
13. Sediment and erosion control measures should not be placed in wetlands or streams.
14. 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.
15. 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. 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.
16. Based on the information presented in the document and presentation 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.
17. 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 NCGO10000.
18. 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.
19. 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.
20. 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.
DHFQ: North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000
21. 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.
22. 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.
23. 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.
24. 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.
25. 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.
26. 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.
27. 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
Joanne Steenhuis at (910) 796-7306 or joanne.steenhuis@ncdenr.gov or Garcy Ward at (252) 948-3917 or
garcy.ward@ncdenr.gov
Electronic copy only distribution:
Brad Shaver, US Army Corps of Engineers, Wilmington Field Office
Tom Steffens, US Army Corps of Engineers, Washington Field Office
Mason Herndon, NCDOT Division 3 Environmental Program Supervisor
Jay Johnson, NCDOT Division 2 Environmental Officer
Cathy Brittingham, NC Division of Coastal Management
Travis Wilson, NC Wildlife
Kristi Lynn Carpenter, NCDWR
Garcy Ward, NC Division of Water Resources Washington Regional Office
File Copy
e:��D—EQ North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000