Biological assessment
PROPOSED AVOIDANCE AND MINIMIZATION MEASURES
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- STANDARD MEASURES
- Bridge Deck Drainage
- Preconstruction Survey
- Agency Coordination
- PROJECT SPECIFIC MEASURES
PROPOSED AVOIDANCE AND MINIMIZATION MEASURESThe following measures are proposed by NCDOT to avoid/minimize potential impacts from construction activities to the Appalachian elktoe and Designated Critical Habitat and Virginia spiraea. These measures are incorporated as “Environmental Commitments” in the construction contract. STANDARD MEASURESA number of avoidance and minimization measures have been incorporated into NCDOT projects that occur within or upstream of water bodies that contain federally protected aquatic species. Erosion Control MeasuresWhenever projects occur in watersheds that contain protected aquatic species, NCDOT develops erosion control measures that exceed the standard BMPs, incorporating the Design Standards in Sensitive Watersheds [15A NCAC 04B .0124 (b) – (e)], regardless of the DWQ stream classification. The areas adjacent to jurisdictional water-bodies in the Cane River and South Toe River watersheds will be identified as “Environmentally Sensitive Areas” on the Sedimentation and Erosion Control Plans for this project. By definition, the Environmentally Sensitive Areas will be identified as a 50-foot (15.2-meter) buffer zone on both sides of the stream measured from top of streambank. Within the identified 50-foot (15.2-meter) Environmentally Sensitive Areas, the following shall apply: In areas identified as Environmentally Sensitive Areas, the Contractor may perform clearing operations, but not grubbing operations until immediately prior to beginning grading operations. Once grading operations begin in identified Environmentally Sensitive Areas, work shall progress in a continuous manner until complete. In areas identified as Environmentally Sensitive Areas, erosion control devices shall be installed immediately following the clearing operation. In areas identified as Environmentally Sensitive Areas, “Seeding and Mulching” shall be performed on the areas disturbed by construction immediately following final grade establishment. In areas identified as Environmentally Sensitive Areas, seeding and mulching shall be done in stages on cut and fill slopes that are greater than 20 feet (6.1 meters) in height measured along the slope, or greater than 2 acres (0.81 hectares) in area, whichever is less. All sedimentation and erosion control measures, throughout the project limits, must be cleaned out when ½ full with sediment, to ensure proper function of the measures. Bridge Deck DrainageNCDOT makes every attempt to eliminate direct deck drainage into water bodies crossed whenever protected aquatic species are present. The design for all bridges within the Cane River and South Toe River watersheds will be designed to eliminate deck drains into the water bodies they cross. Although design information has not been finalized for the R-2519B section of the project, bridges within the North Toe River drainage will also be designed to eliminate direct discharge. Currently drainage from the decks of these existing structures flows directly into the water bodies they cross. The amount of direct discharge from the roadway entering these water bodies will be reduced with the new structures. This commitment has been incorporated in the Structure Design Plans for the R-2518B and R-2519A segments of the project and will be incorporated into the R-2519B segment. Preconstruction SurveyNCDOT conducts final surveys (just prior to construction) in the project footprint of projects impacting waters known to contain protected mussel species. NCDOT is anticipating that the Appalachian elktoe will be found in surveys of the project footprint at the South Toe River crossing, and possibly the Cane River crossing, and is proposing to relocate these mussels to appropriate upstream habitat. The pre-construction survey will be incorporated into the relocation plan that has been developed (See Conservation Measures-Proposed Measures to Offset Impacts, Section 7.1). NCDOT and the Catena Group Inc. have successfully relocated other federally protected freshwater mussel species, including the Appalachian elktoe from other project footprints. Agency CoordinationNCDOT will invite representatives from USFWS and the NCWRC to the pre-construction meeting for these projects, as well as to all subsequent field inspections prior to construction, to insure compliance with all special project commitments. PROJECT SPECIFIC MEASURESAvoidance and minimization measures specific to this project have been developed to avoid/minimize adverse impacts to water quality and in turn the Appalachian elktoe. Additionally, due to concerns raised by the US Fish and Wildlife Services over Japanese knotweed, the North Carolina Department of Transportation has identified the existence of Japanese Knotweed within the project limits of R-2518 and R-2519 and measures have been developed to minimize the threat of this invasive species on the Appalachian elktoe and Virginia spiraea. Retaining Walls NCDOT has designed retaining walls to be constructed at various stream crossings to reduce/avoid stream impacts (Table 12). Although these stream segments do not provide suitable habitat for the Appalachian elktoe, they flow into a reach of either the South Toe River, or North Toe River, which are occupied by the Appalachian elktoe and is also Designated Critical Habitat. Reducing impacts in these streams will minimize potential downstream impacts, such as sedimentation, erosion, and stream-bank instability (See Direct Impacts) to the Appalachian elktoe and Critical Habitat. Table 12. Retaining walls designed to reduce stream impacts.
* Reduce/eliminate fill in floodplain Selection of Bridge vs. Culvert The decision to use culverts to convey stream flow and gain access over a waterway is commonly used for economic factors, as they are less expensive, require less maintenance, and last longer than bridges. However, culverts generally impact a larger area of the stream and have a higher potential for stream scour than bridges. The original design for this project called for a Reinforced Concrete Box Culvert (RCBC) at the Bald Creek crossing at Station # 175+60 –L-. This crossing is 0.7 miles (1.1 kilometers) from the Cane River, which is occupied by the Appalachian elktoe in this reach. To minimize permanent impacts to Bald Creek at this location, and potential downstream impacts to the Appalachian elktoe, NCDOT has changed the proposed crossing structure to a bridge. Japanese Knotweed Control Due to concerns of the US Fish and Wildlife Services, the North Carolina Department of Transportation has identified the existence of Japanese Knotweed (Fallopia japonica) within the project limits of R-2518 and R-2519. The plant is considered an invasive species that can reproduce from its seed or from its long stout rhizomes. It can tolerate a variety of conditions such as full shade, high temperatures, high salinity, and drought. Wind, water, and soil movement are all means by which this species can spread. Japanese knotweed can quickly form dense thickets that exclude native vegetation and greatly alter the natural ecosystem. To minimize the potential spread of Japanese knotweed from construction-related activities, the Department proposes to attempt to suppress the Japanese Knotweed within NCDOT Right of Way at the following locations: R-2518A Mitigation Site 1, R-2518B Mitigation Site 4, R-2518B Bridge at Sta. 223+50 (Cane River Bridge) and R-2519B Bridge at Sta. 121+00 (South Toe River Bridge), with the application of a glyphosate herbicide, according to the product label. Treatment will only occur prior to disturbance of the area since the application of the herbicide will create the potential for erosion to occur. Once the grading operations are complete and a stabilized vegetative cover has been established, an annual spot treatment will occur at the bridge locations to suppress the Japanese Knotweed until traffic is allowed to travel the new roadway. For the mitigation sites, the species will be treated for the five (5) year monitoring period. The Department of Transportation will put forth its best effort to suppress the Japanese Knotweed population with the use of aquatic labeled glyphosate, but it can not guarantee the eradication of the species using this method. Additionally, the contract(s) for this project will stipulate that any knotweed material disturbed through construction activities at the two bridges as well as identified mitigation sites will be buried within the project boundaries in fill or waste area below the depth of the topsoil. NCDOT prefers this action to allowing the contractor to haul it offsite because it will no longer have control over proper disposal. The Department would also like to state that adequate research has not been performed to-date on the adverse effects of an aquatic labeled glyphosate on mussel species. Therefore, while the Department plans to use the most appropriate herbicide and application procedures, it can not guarantee there will be no negative effects on mussel species within the project area. Directory: resources -> Environmental resources -> North Carolina Inclusion Initiative Mapping Where Children with ieps are Being Served Purpose resources -> Practice learning resources -> The Rise of Video Games Section “Word” Matt Spencer resources -> Request for proposal contract form for the transit industry resources -> Request for Proposal [insert date] resources -> The University of York 13th 16th April 2004 resources -> Biological and Biomedical Sciences Program Community Education Initiative resources -> Region III standing regional response team (rrt) meeting williamsburg, Virginia Thursday, January 12, 2012 resources -> Efca eastern District and TouchGlobal, the crisis response ministry of efca Environmental -> Preparing Natural Resource Technical Reports Download 0.94 Mb. Share with your friends:
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