HomeMy WebLinkAboutDiv 11 Bridge Scope June' .
PAT MCCRORY
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DONALD R. VAN DER VAART
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WaterResources S. JAY ZIMMERMAN
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June 6, 2016
MEMORANDUM
TO: Chrisry Huff, NCDOT (chuff@ncdot.gov)
FROM: Dave Wanucha, NC Division of Water Resources, Winston Salem Office �tY �' ���
SUBJECT: Scoping Review of NCDOT's Proposed Bridge Replacement Projects
In reply to your electronic correspondence dated May 20, 2016 in which you requested comments for the projects
referenced below in Table l, the NC Division of Water Resources offers the following:
Table 1. NCDOT Division 11 bridge proiects in Wata
Bridge Number I Stream I Stream Index I Stream
.-�..___r__.
Middle Fork
136 SouthForkNew ]0-1-2-(6)
River
22 Beaver Dam 8 19
Creek
WS IV; Tr+
C; Tr
River Basin
New
Watauga
303(d) List
No
Yes; Poor Fish
Both streams listed above are 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 shall be conducted in accordance with NC Division of
Land Resources and NC Wildlife Resources Commission requirements.
2. Review of the project reveals the presence of surface waters with a special designation "+" which identifies
waters subject to a special management strategy specified in 15A NCAC 2B. 0225 the Outstanding Resource
Waters (ORW) Rule, in order to protect downstream waters designated as ORW. The water quality
classification of ORW is one ofthe highest classifications in the State. The NCDWR is e�:tremely concerned
with any impacts that may occur to streams with this classification. It is preferred that these resources be
avoided if at all possible. If it is not possible to avoid these resources, the impacts shouid be minimized to the
greatest extent possible. 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 A124) throughout design and construction of the project.
3. Provided the project meets the requirements ofNCDOT NPDES permit NCS000250, no application for
individual SYate Stormwater permit will be required (Streamlining State Stormwater Permitting for NCDOT
Projects letter, July 26, 2013).
S[a[e of North Cazolina IEnvironmen[al Quality � Water Resources
1617 Mail Service Center, Raleigh, North Camlina 2769&1617
Ceneral Comments Regarding Bridge Replacement Projects
4. The NCDWR is very concerned with sediment and erosion impacts that could result from this project. NC DOT
shall address these concems by describing the potential impacts that may occur to the aquatic environments and
any mitigating factors that would reduce the impacts.
5. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved under
General 401 Certification Number 3883/Nationwide Permit No. 6 for Survey Activities.
6. 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 (ACE) to determine the
required permit(s).
7. If the old bridge is removed, no dischazge of bridge material into surface waters is allowed unless otherwise
authorized by the ACE. Strict adherence to the Corps of Engineers guidelines for bridge demolition will be a
condition of the 401 Water Quality Certification.
8. 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.
9. 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 NCS0000250, please refer
to the most recent version of the North Carolina Department of Transportation Stormwater Best Management
Practices Toolbox manual for approved measures
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.
l l. Bridge supports (bents) shall not be placed in the stream when possible.
12. [f temporary access roads or detours aze 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 deared 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.
l3. 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.
14. 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.
15. 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.
16. In most cases, the NCDWR prefers the replacement of the existing structure at the same location with road
closure. [f road closure is not feasible, a temporary detour shall be designed and located to avoid wetland
impacts, minimize the need for cleariog and to avoid destabilizing stream banks. [f 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.
17. Placement of culverts and other structures in waters, streams, and wetlands shall be 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 encouotered 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 induding pipes or barrels at flood plain elevation and/or sills where appropriate. Widening the
stream channel shall be avoided. Stream channel widening at the inlet or outlet end of structures typically
decreases water velociry causing sediment deposition that requires increased maintenance and disrupts aquatic
life passage.
19. Riprap shall not be placed i� the active thalweg channel or placed in the streambed in a manner that precludes
aquatic liFe passage. Bioengineering boulders or structures shall be properly designed, sized and installed.
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
Dave Wanucha at (336) 776-9703 or at Dave.Wanucha@ncdenr.gov.
Electronic copy only distribution:
Steve Kichefsky, US Army Corps of Engineers, Asheville Field Office
NC Division of Water Resources Raleigh Central Office
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