Scoping Comments Bridge 29_BR-0194_Onslow Co

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

May 19, 2023
MEMORANDUM ____

TO: Derek R. Pielech, NCDOT

FROM: Hannah Sprinkle, NC Division of Water Resources, Wilmington Office

SUBJECT: Scoping comments for the proposed replacement of Bridge 29 over Chainey Creek on US 17 in Onslow
County, BR-0194.

In reply to your correspondence dated May 15, 2023, in which you requested comments for the above referenced
projects. Preliminary analysis of the project reveals the potential for multiple impacts to streams and jurisdictional
wetlands in the project area. The NC Division of Water Resources offers the following comments:

Stream Name River Basin Stream Classification(s) Stream Index
Number
303(d)
Listing
Chainey Creek White Oak SC; NSW 19-10 n/a
*surface water present in the general vicinity of project area

Project Specific Comments:
1. Chainey Creek are class SC; NSW waters of the State. The NCDWR is very concerned with sediment and
erosion impacts that could result from this project. The NCDWR recommends that highly protective
sediment and erosion control BMPs be implemented to reduce the risk of nutrient runoff to Chainey Creek.
Post-construction stormwater BMPs should, to the MEP, be selected and designed to reduce nutrients.
General Project Comments:

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 Program Manual, and the Stormwater 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. 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(c), 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. 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.

5. 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[c]), mitigation will be required

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

for impacts of greater than 1/10th 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.

6. In accordance with the Environmental Management Commission’s Rules (15A NCAC 2H.0506[c]),
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.

7. 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.

8. The NCDWR is very concerned with sediment and erosion impacts that could result from this project. NC
DOT 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.

9. 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.

10. 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.

11. 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.

12. Whenever possible, the NCDWR prefers spanning structures. Spanning structures usually do not require
work within the stream or grubbing of the stream banks and do not require stream channel realignment.
The horizontal and vertical clearances provided by bridges allow for human and wildlife passage beneath
the structure, do not block fish passage and do not block navigation by canoeists and boaters.

13. 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 current version of NCDWR Stormwater
Best Management Practices.

14. Sediment and erosion control measures should not be placed in wetlands or streams.

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. If a bridge is being replaced with a hydraulic conveyance other than another bridge, the NCDWR believes
the use of a Nationwide Permit may be required. Please contact the US Army Corp of Engineers to
determine the required permit(s).

17. If the old bridge is removed, no discharge of bridge material into surface waters is allowed unless otherwise
authorized by the US ACOE. Strict adherence to the Corps of Engineers guidelines for bridge demolition
will be a condition of the 401 Water Quality Certification.

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

18. Bridge supports (bents) shall not be placed in the stream when possible.

19. 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.

20. 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.

21. 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.

22. All work in or adjacent to stream waters shall be conducted in a dry work area unless otherwise approved
by the NCDWR. Approved BMP measures from the most current version of 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.

23. Heavy equipment shall 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.

26. 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.

27. In most cases, the NCDWR prefers the replacement of the existing structure at the same location with road
closure. If road closure is not feasible, a temporary detour shall be designed and located to avoid wetland
impacts, minimize the need for clearing and to avoid destabilizing stream banks. If the structure will be on
a new alignment, the old structure shall be removed and the approach fills removed from the 100-year
floodplain. Approach fills shall be removed and restored to the natural ground elevation. The area shall be
stabilized with grass and planted with native tree species. Tall fescue shall not be used in riparian areas.

28. Based on the information presented in the document, the magnitude of impacts to wetlands and streams
may require an Individual Permit (IP) or Nationwide (NW) application to the Corps of Engineers and

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

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.

Thank you for requesting our input at this time. The DOT 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
Hannah Sprinkle at [e-mail].
.

Electronic copy only distribution:

Mason Herndon, NCDOT
Thomas A. Steffens, USACE Washington Regulatory Field Office (via email)
Travis Wilson, NC Wildlife Resources Commission  
Kimberlee Harding, Department of Marine Fisheries