HomeMy WebLinkAbout20120313 Ver 0_Scoping Comments_20090224NC®ENR
North Carolina Department of Environment and Natural Resources
Beverly Eaves Perdue
Governor
Division of Water Quality
Coleen H. Sullins
Director
Dee Freeman
Secretary
February 24, 2009
MEMORANDUM
To: Greg Blakeney, Bridge Project Planning Engineer, NCDOT PDEA
From: Polly Lespinasse, NC Division of Water Quality, Mooresville Regional Office
Subject: Scoping Comments on Proposed Replacement of Bridge No. 6 on SR 2014 (Lakeview
Road) in Gaston County, Federal Aid Project No. BRSTP-2014(3), WBS 38524.1.1, TIP No.
B-4752
Please reference the correspondence dated February 12, 2009, in which you requested comments for the
above referenced project. Preliminary analysis of the project reveals the potential for multiple impacts to
perennial streams and jurisdictional wetlands in the project area. More specifically, impacts to:
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The Division of Water Quality (DWQ) requests that NCDOT consider the following environmental issues for the
proposed project:
General Project Comments:
1. 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 21-1.0506(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.
2. Environmental assessment alternatives should consider design criteria that reduce the impacts to
streams and wetlands from storm water runoff. These alternatives should include road designs that
allow for treatment of the storm water runoff through best management practices as detailed in the
most recent version of NC DWQ Stormwater Best Management Practices, such as grassed swales,
buffer areas, preformed scour holes, retention basins, etc.
Mooresville Regional Office
Location: 610 East Center Ave., Suite 301 Mooresville, NC 28115
Phone: (704) 663-16991 Fax: (704) 663 60401 Customer Service: 1-877-623.6748
Internet: www.ncwalerqual ty.org
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Mr. Greg Blakeney
Page Two
3. 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 should be designed to replace appropriate lost functions and values. The NC
Ecosystem Enhancement Program may be available for use as wetland mitigation.
4. In accordance with the Environmental Management Commission's Rules (15A NCAC 2H.0506(h)),
mitigation will be required for impacts of greater than 150 linear feet to any single perennial stream. In
the event that mitigation is required, the mitigation plan should be designed to replace appropriate lost
functions and values. The NC Ecosystem Enhancement Program may be available for use as stream
mitigation.
5. DWQ is very concerned with sediment and erosion impacts that could result from this project. 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.
6. If a bridge is being replaced with a hydraulic conveyance other than another bridge, DWQ believes the
use of a Nationwide Permit may be required. Please contact the US Army Corp of Engineers to
determine the required permit(s).
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.
8. Bridge supports (bents) should not be placed in the stream when possible
9. Whenever possible, the DWQ 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 allow for human and wildlife passage
beneath the structure, do not block fish passage and do not block navigation by canoeists and boaters.
10. 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 NC
DWQ Stormwater.Best Management. Practices.
11. 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.
12. If temporary access roads or detours are constructed, the site shall 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.
Mr. Greg Blakeney
Page Three
13. 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 down stream of the above
structures. The applicant is required to provide evidence that the equilibrium is being maintained if
requested in writing by DWQ. If this condition is unable to be met due to bedrock or other limiting
features encountered during construction, please contact the NC DWQ 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 should be designed to mimic natural stream cross section
as closely as possible including pipes or barrels at flood plain elevation and/or sills 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. If foundation test borings are necessary; it should be noted in the document. Geotechnical work is
approved under General 401 Certification Number 3494/Nationwide Permit No. 6 for Survey Activities.
16. 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.
17. All work in or adjacent to stream waters should be conducted in a dry work area unless otherwise
approved by NC DWQ. 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 should be used to prevent excavation in flowing water.
18. Sediment and erosion control measures should not be placed in wetlands and streams.
i
19. Borrow/waste areas should avoid wetlands to the maximum extent practical. Impacts to wetlands in
borrow/waste areas could precipitate compensatory mitigation.
20. 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.
21. 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.
22. In most cases, the DWQ 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.
Mr. Greg Blakeney
Page Four
23. Riprap should 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.
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 Polly Lespinasse at (704) 663-1699.
cc: Steve Lund, US Army Corps of Engineers, Asheville Field Office
Chris Militscher, USEPA (electronic copy)
Marla Chambers, NC Wildlife Resources Commission (electronic copy)
Marella Buncick, US Fish and Wildlife Service (electronic copy)
Sonia Gregory, DWQ Central Office