20120977 Ver 0_Scoping Comments_20081117

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November 17, 2008
MEMORANDUM
To Tracy A Walter, Bridge Project Planning Engineer
Project Development and Environmental Analysis Branch
NC Department of Transportation
From Michael R Parker, NC Division of Water Quality, Asheville Regional Office 1410
Subject Scoping comments on proposed replacement of Bridge No 11, NC Highway 175 in Clay
County, Federal Aid Project No BRSTP-175(7), WBS Element No 38506 1 1,
TIP Project No B-4733
This office has reviewed the correspondence dated October 28, 2008 in which you requested comments
for the referenced project The Division of Water Quality (DWQ) is responsible for the issuance of the
Section 401 Water Quality Certification for activities that impact Waters of the U S , including wetlands
Based on a preliminary review of the project study area, tributaries, wetlands and riparian buffers
associated with the following named stream(s) that could be impacted by the proposed project
Stream Name River Basin Stream
Classification(s) Stream Index
Number
Chatu e Lake Hiwassee B 1-(1)
DWQ has the following comments
Project Specific Comments
B-4733, Bridge No 11 over Chatuge Lake in Clay County
Lake Chatuge is class B waters of the State DWQ has no specific comments regai ding this
project
2 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
Any anticipated bank stabilization associated with bridge construction 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 bank stabilization necessary due to bridge
construction
N ehCar
Nouturs
North Carolina Division of Water Quality 2090 US Highway 70 Swannanoa NC 28778 Phone [phone] Customer Service
Internet www ncwaterquality org FAX [phone]
Michael F Easley Governor
William G Ross Jr, Secretary
North Carolina Department of Environment and Natural Resources
Coleen Sullins, Director
Division of Water Quality
An Equal Opportunity/Affirmative Action Employer- 50% Recycled/10% Post Consumer Paper
General Comments Regarding Bridge Replacement Projects-
4 The environmental document shall 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 2H 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
5 Environmental assessment 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 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
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 {I SA 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 shall be designed to replace appropriate lost
functions and values The NC Ecosystem Enhancement Program may be available for use as
wetland mitigation
7 In accordance with the Environmental Management Commission's Rules (I 5A 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 shall be designed to
replace appropriate lost functions and values The NC Ecosystem Enhancement Program may be
available for use as stream mitigation
R DWQ is very conceined with sediment and erosion impacts that could result from this project
NC DO F shall address these concet us by desci ibing the potential impacts that may occur to the
aquatic environments and any mitigating factors that would reduce the impact-
9 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)
10 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
11 Bridge supports (bents) shall not be placed in the stream when possible
12 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
13 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
14 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 sui face waters due to the potential for elevated pH and
possible aquatic life and fish kills
15 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 should 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
16 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 encounteied 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
17 If multiple pipes or bariels are iequiied, they shall be designed to mimic natural stream cross
section as closely as possible including pipes or Wirels at flood plain elevation and/or sills wheie
appropriate Widening the stream channel shall be avoided Stieam channel widening at the inlet
or outlet end of structures typi(,ally decreases water velocity causing sediment deposition that
requnes incieased maintenance and disiupts aquatic life passage
18 If foundation test borings are necessary, it should be noted in the document Geotechnical work
is approved under General 401 Certification Number 3624/Nationwide Permit No 6 for Survey
Activities
19 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
20 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 should be used to prevent excavation in flowing water
21 Sediment and erosion control measures shall not be placed in wetlands and streams
22 Borrow/waste areas shall avoid wetlands to the maximum extent practical Impacts to wetlands
in borrow/waste areas could precipitate compensatory mitigation
23 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
24 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
25 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 shall 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 shall be stabilized with grass and planted with
native tree species Tall fescue shall not be used in riparian areas
26 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
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 of requite
additional information, please contact Mike Parker at [phone]
cc David Baker, US Army Corps of Enguieef s, Asheville Field Office
Clarence Coleman, Federal Highway Administfation
Marla Chambers, NC Wildlife Resources Commission
Transportation Permitting Unit
Asheville Regional Office Copy