Loading...
HomeMy WebLinkAbout20120977 Ver 0_Scoping Comments_20081117o? \ NA r?9Qc r > -t T-1 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 (828) 296-4500 Customer Service Internet www ncwaterquality org FAX (828) 299-7043 1-877-623-6748 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 (828) 296-4500 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