20151193 Ver 1_Memorandum of Understanding_20101229

ZT-WAA
NC®ENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
MEMORANDUM
TO: Natalie Lockhart, Bridge Project Planning Engineer, NCDOT
Dee Freeman
Secretary
FROM: Polly Lespinasse, NC Division of Water Quality, Mooresville Regional Office
SUBJECT: Scoping Review of NCDOT's Proposed Bridge Replacement Project, STIP Project No.
B-4751, Replacement of Bridge No. 203 on State Road 1935 over Stanley Creek in Gaston
County
In reply to your correspondence dated December 29, 2010, and received electronically on December 29, 2010, in which
you requested comments for the above referenced project, the NC Division of Water Quality (DWQ) offers the following
comments:
Project Specific Comments:
Stanley Creek is a Class WS-IV, 303(d) Waters of the State. Stanley Creek is on the 303(d) list for impaired use for
aquatic life due to low dissolved oxygen. NCDW Q is very concerned with sediment and erosion impacts that could
result from this project. NCDWQ requests that road design plans provide treatment of the stormwater runoff best
management practices as detailed in the most recent version of NCDWQ Stormwater Best Management Practices.
2. Any anticipated bank stabilization associated with culvert installations or extensions should be addressed in the
Categorical Exclusion (CE) document. It is understood that final designs are not determined at the time the CE is
developed. However, the CE should discuss the potential for bank stabilization necessary due to culvert
installation.
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
DWQ 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.
2. If foundation test borings are necessary; it shall be noted in the document. Geotechnical work is approved under
General 401 Certification Number 3687/Nationwide Permit No. 6 for Survey Activities.
3. 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).
Mooresville Regional Office
Location: 610 East Center Ave., Suite 301 Mooresville, NC 28115
Phone: [phone] \ Fax: [phone] \ Customer Service: 1.877-62&6748
Internet: htlol/ooral.ncdenr.oro/wela6p
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4. 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.
5. Whenever possible, the DWQ 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.
6. 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 NC DWQ Stormwater Best Management Practices.
7. 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.
8. Bridge supports (bents) shall not be placed in the stream when possible.
9. 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.
10. 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.
11. All work in or adjacent to stream waters shall 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 shall be used to prevent
excavation in flowing water.
12. 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.
13. 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 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.
General Comments if Replacing the Bridge with a Culvert
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.
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2. 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 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
velocity causing sediment deposition that requires increased maintenance and disrupts aquatic life passage.
3. 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 shall 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 implemented 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 [phone].
cc: Liz Hair, US Army Corps of Engineers, Asheville Field Office (electronic copy)
Chris Militscher, Environmental Protection Agency (electronic copy)
Marla Chambers, INC Wildlife Resources Commission (electronic copy)
Marella Buncick, US Fish and Wildlife Service (electronic copy)
Sonia Gregory, DWQ Central Regional Office (electronic copy)
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