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Environmental Assessment Worksheet Nature's Refuge Conservation Development Lino Lakes, Anoka County, Minnesota Draft Document — September 25, 2006 Page 25 The rare plant species found on the site are all native wetland plants that respond well to wetland restoration measures that are planned for the conservation areas. However, a minority of populations of these plants presently occur in wetlands that would be filled by the project. This will constitute a taking of rare plant populations which will require a permit from the DNR. The DNR has expressed initial support for this approach on condition that the conservation areas be fully restored and maintained as improved habitat for these plant species. Also, attempts will be made to transplant existing populations from those wetlands that will be filled into wetlands that will be restored. Because future active restoration and management activities are primarily aimed at restoring and maintaining native plant communities, the populations of rare species are expected to continue and possibly expand. Flood Elevation A portion of the site lies within a delineated 100 -year flood plain. The project will result in a re- grading of part of the site, so changes to the flood elevation contour will be required. Construction and re- grading in the present flood zone will be minimized, because only one street will cross the flood plain and no houses will be located within it. Compensatory storage will be created for any floodplain fill. The FEMA floodplain map will be revised. Drainage and Sedimentation The project will be designed to avoid altering drainage conditions. Runoff will be directed to vegetated swales, rain gardens, and infiltration ponds. Sedimentation ponds and rain gardens will be designed in accordance with City of Lino Lakes requirements and both are proposed to treat storm water runoff before discharge. The ponds will be designed to retain a 100 -year storm event and control the discharge rate to pre - development conditions. Drainage from residential areas and impervious surfaces will be directed into infiltration areas in order to prevent sedimentation or contamination of wetlands, to control inflow rates, and to maintain present hydrology as well as possible. Infiltration ponds will be protected from soil compaction by construction equipment, and any compacted areas will be disked to de- compact the soil, which will ensure water infiltration and successful re- vegetation. Erosion Control Erosion control measures will be implemented in accordance with the Storm Water Pollution Prevention Plan (SWPPP) developed for this project to mitigate the potential for adverse surface water and air quality impacts from runoff and wind erosion during construction. The SWPPP will incorporate Best Management Practices prescribed by the MPCA. These measures, including silt fencing, ditch checks, stone exit pads, and prompt turf restoration (including de- compacting, mulching, seeding) in graded areas. The phasing of construction will minimize the area of soil exposed at any given time. Water Use and Wastewater The development, when fully occupied by residents, is expected to consume approximately 76,450 gallons of water from City water supply each day. An approximately equal amount of waste water will be delivered to the City sewage treatment system. These demands are within the capacity of existing infrastructure and systems. Construction- Related Hazardous Materials, Noise, and Dust Typical liquid materials associated with construction equipment, such as engine oils and coolants, may be temporarily stored on site during construction. Spills are also possible. Standard BMPs will be employed to minimize the likelihood of spills, and the impact of any spills that may occur. Similarly, dust -and- erosion - reduction BMPs will be employed. Additional noise generation will be typical of any residential construction activity and will cease after the construction phase. Traffic and Air Quality The project will generate a considerable quantity of new traffic, particularly on CSAH 14. Completing the improvements indicated in the Traffic Impact Analysis will mitigate the additional traffic volume so as to not adversely impact the traffic flow on adjacent roadways. Air quality will not be significantly impacted by the traffic increase and proposed residential land use. •