Environmental Assessment June 1989

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2.7 WETLANDS Wetlands do not occur on the site. However, two wetland areas adjacent to the site may be affected by airport improvements. Anoka County Wetland No. 117 is immediately east of the proposed runway (Figure 2-11). Wetland No. 117 is a Type 3 wetland, a protected classification. This wetland currently receives storm water runoff from the airfield and would continue to receive runoff. If necessary, a storm water detention basin will be built to detain runoff water before itsrelease to the wetland. Final design grades of the site must be set before the need for a detention basin can be determined, however, adequate area is available on the proposed property to accomodate this possibility. The relocation of County Road 116 may affect Anoka County Wetland No. 118, a Type 3 wetland, which is located north of the site. County 116 will be relocated north of its present alignment to accomodate lengthening of the runway to the northwest. Preliminary alignment of CSAH 116 indicates that no wetland acreage will be impacted by filling or excavation. A portion of the wetland may be included in the 120' right of way. Final design grades and right-of-way must be determined as well as establishing the actual wetland edge before any impact on the wetland can be assessed. Impacts are expected to be minimal. Under a worst case situation with the roadway alignment shifted 50' to the east, less than one half acre of wetland would be impacted by filling. The wetlands will be protected by erosion control measures and sedimentation traps during the construction and thereafter until the turf is established. If filling would be required, design and construction would be coordinated with the Corps of Engi- neers, Department of Natural Resources, and if appropriate U.S. Fish and Wildlife Services. Specific mitigation measures may include enhancement of the existing wetland or another wet- land within the community. The wetlands may be used as natural drainage basins for storm water runoff from the proposed site. 2.8 AIR QUALITY Air pollutants are measured according to two sets of standards - Primary and Secondary. The Primary standards are set such that the average concentrations given for a set period of time repre- sent the maximum allowable limits which do not affect the health of the general public. Secondary standards are set at a level such that the average concentrations given for a set period of time represent the maximum allowable limits at which no adverse effects on soil, water, vegetation, materials, animals, visi- bility or personal comfort and well being are experienced. Minnesota utilizes the Federal Ambient Air Quality Primary and 2-26