BR-0250_DWR Comments

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
MEMORANDUM
NORTH CAROLINA
Environmental Quality
September 25, 2023
To: Nick Pierce, NCDOT Project Engineer, Structures Management Unit (napierce@ncdot. ov�^^s
From: Dave Wanucha, NC Division of Water Resources, Transportation Permitting Branch /25/2023
Subject: Comments on proposed bridge replacements in NCDOT Division 11 (BR-0250) comprising three bridges:
Bridge 149 in Avery County; Bridge 252 in Caldwell County; and, Bridge 231 in Watauga County.
Reference correspondence dated September 18, 2023, in which you requested comments for the referenced project.
Preliminary analysis of the project reveals the potential for impacts to streams and jurisdictional wetlands in the
project. More specifically, impacts to:
Stream
Stream Index
303(d)
Stream and Bridge
River Basin
County
Classifications
Number
Listing
Horse Creek
French Broad
WS-V; Trout
7-2-9
Avery
Bride 149
UT to Zacks Fork Creek
Bride 252
Catawba
C
11-39-1
Caldwell
no
Norris Fork
Bridge 231
New
C; Trout
10-1-10-2
Watauga
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 project.
Project Specific Comments:
General Project Comments:
1. 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 Toolbox manual, such as grassed
swales, buffer areas, preformed scour holes, retention basins, etc.
2. 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 and wetland
impacts greater than 0.10 acre. 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. 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.
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

4. NCDWR is very concerned with sediment and erosion impacts that could result from this project. 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.
5. Horse Creek and Norris Fork are classified as Trout (Tr) waters of the State. The NCDWR recommends that
the most protective sediment and erosion control BMPs be implemented to reduce the risk of turbidity
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 maximum extent practicable (MEP), be selected and designed to
reduce TSS and avoid a sustained increase in the receiving water temperature. Given the potential for impacts
to these resources during project implementation, 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.
6. 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.
7. Where streams must be crossed, 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, NCDOT should
not install the bridge bents in the creek, to the maximum extent practicable.
8. 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.
9. Sediment and erosion control measures should not be placed in wetlands or streams.
10. 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.
11. 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. Please refer to the most recent version of the North Carolina Department of
Transportation Stormwater Best Management Practices Toolbox manual for approved measures.
12. 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.
13. 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 NCDWR. If
this condition is unable to be met due to bedrock or other limiting features encountered during construction,
Q7: > North Carolina Department of Environmental Quality I Division of Water Resources
a:E
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000

please contact NCDWR for guidance on how to proceed and to determine whether or not a permit
modification will be required.
14. 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.
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.
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 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. NCDOT is reminded that issuance of a 401 Water Quality
Certification (or applicable General 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 [phone] or [e-mail].
Electronic copy:
File
Q7: > North Carolina Department of Environmental Quality I Division of Water Resources
a:E
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
919.707.9000