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Design Considerations for Minimizing Road IDroject Impacts to Wetlands To qualify for the Board of Water and Soil Resources (BWSR) public road wetland. replacement program, public transportation authorities must ensure that projects minimize the amount of wetland filling or draining (Minn. Rule Chapter 8420.0540, subp.~.D.(1)). Listed below are a variety of design features that have been employed in the construction of roads in Minnesota to minimize wetland impacts. Road authorities should consider incorporating these design features whenever practical and feasible and public safety will not be compromised (Note: a variance from state-aid standards is required). ' Steeper side slopes (4:1 or steeper); utilizing guard rail if necessary ' Lower vertical profiles ' "Broken back" side slopes for roads with a high vertical profile (unless a gradual slope into the wetland fringe is preferred) ' Reduced radius curves Use of bridges, rather than fill and culverts ' Narrow shoulders {unless needed for bikers and pedestrians) ' Minimum safe sight distances, to minimize the need. for cut and fill ' Turn lanes instead of frontage roads ' Reduced speed design ' Designation of road as a "Natural Preservation Route" to allow reduced design standards ' Construct ditches so that wetland outlets are not lowered Ensure that the location or design of a road does not significantly reduce the contributing watershed of a wetland, resulting in changes to the hydrologic regime Early coordination with natural resource and regulatory agencies is an effective way to ensure that wetland impacts are minimized. For assistance contact the Technical Evaluation Panel members (Local Government Unit, Soil and Water Conservation District, Board of Water and Soil Resources field staff), MnDOT -- Environmental Services Office, Department of Natural Resources field staff or Ecological Services Section, or the U.S. Army Corps of Engineers project. manager. a: roadm i. w60