20120450_Scoping Comments_20090914

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NC®ENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
September 14, 2009
MEMORANDUM
TO: Brenna Poole, NCDOT
FROM: David Wainwright, NCDWQ
Dee Freeman
Secretary
SUBJECT: Scoping Review of NCDOT's Proposed Bridge Replacement Project B- 4488; Bridge No. 176 on
SR 1763 over Slocum Creek in Craven County
in reply to your correspondence dated September 1, 2009 (received September 9, 2009) in which you requested
comments fdr the above referenced projects, the NCDWQ offers the following comments:
Project-Specific Comments
Slocum Creek is class C;Sw,NSW waters of the State. The NCDWQ is very concerned with sediment and
erosion impacts that could result from this project. The NCDWQ recommends that highly protective
sediment and erosion control BMPs be implemented to reduce the risk of nutrient runoff to Slocum Creek.
NCDWQ requests that road design plans provide treatment of the storm water runoff through best
management practices as detailed in the most recent version of NCDWQ's Stormwater Best Management
Practices.
2. This project is within the Neuse River Basin. Riparian buffer impacts should be avoided and minimized to
the greatest extent possible pursuant to 15A NCAC 2B.
3. Any anticipated dewatering or access structures necessary for construction of bridges should be addressed
in the CE. It is understood that final designs are not determined at the time the CE is developed. However,
the CE should discuss the potential for dewatering and access measures necessary due to-bridge
construction.
General Comments Regarding Bridge Replacement Projects
4. The NCDWQ is very concerned with sediment and erosion impacts that could result from this project. The
NCDOT should 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. If foundation test borings are necessary; it should be noted in the document. Geotechnical work is approved
under General 401 Certification Number 3687/Nationwide Permit No. 6 for Survey Activities.
6. 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.
7. Whenever possible, the NCDWQ 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 should allow for human and wildlife passage beneath
Transportation Permitting Unit
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Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
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the structure. Fish passage and navigation by canoeists and boaters should not be blocked. Bridge supports
(bents) should not be placed in the stream when possible.
8. Bridge deck drains should not discharge directly into the stream. Stormwater should 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 the NCDWQ's
Stormwater Best Management Practices.
9. If concrete is used during construction, a dry work area should be maintained to prevent direct contact
between curing concrete and stream water. Water that inadvertently contacts uncured concrete should not
be discharged to surface waters due to the potential for elevated pH and possible aquatic life and fish kills.
10. If temporary access roads or detours are constructed, the site should be graded to its preconstruction
contours and elevations. Disturbed areas should be seeded or mulched to stabilize the soil and appropriate
native woody species should be planted. When using temporary structures the area should 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.
11. 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.
12. All work in or adjacent to stream waters should be conducted in a dry work area unless otherwise approved
by NCDWQ. 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
should be used to prevent excavation in flowing water.
13. 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
should be inspected daily and maintained to prevent contamination of surface waters from leaking fuels,
lubricants, hydraulic fluids, or other toxic materials.
14. In most cases, the NCDWQ prefers the replacement of the existing structure at the same location with road
closure. If road closure is not feasible, a temporary detour should 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 should be removed and the approach fills removed from the 100-year
floodplain. Approach fills should be removed and restored to the natural ground elevation. The area should
be stabilized with grass and planted with native tree species. Tall fescue should not be used in riparian
areas.
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 David Wainwright at [phone].
cc: William Wescott, US Army Corps of Engineers, Washington Field Office
Kathy Matthews, Environmental Protection Agency (electronic copy only)
Travis Wilson, NC Wildlife Resources Commission (electronic copy only)
Steve Sollod, Division of Coastal Management
Garcy Ward, NCDWQ Washington Regional Office
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