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Adelaide Landing Residential Development EAW, Hugo January 31, 2017 Prairie Du Chien -Jordan Aquifer is moderate (M). Sensitivity of groundwater systems to pollution is defined as the approximate time it takes from the moment a contaminant infiltrates the land surface until it reaches an aquifer. As stated above, the average depth to groundwater on the site is estimated at approximately 6 feet below ground surface on average. Shallow groundwater in fine to medium - grained sandy soils can be susceptible to contamination. As such, the site will be developed in accordance with the requirements of the MPCA General Stormwater Permit for Construction Activity (Minnesota Stormwater Manual). The project will also adhere to the stormwater management and infiltration requirements identified in the City of Hugo Comprehensive Stormwater Management Plan and requirements included in the and joint powers agreement with Rice Creek Watershed District, as required and warranted (City of Hugo 1996). Deep basins to be used for water reuse, aesthetics and earthwork balancing purposes will interact with groundwater. All surface drainage will be treated via water quality ponds prior to discharging to the deep basins. The residential development will also offer a higher level of groundwater protection and mitigation than exists under the current agricultural conditions. Because development will be typical of residential uses, no unusual wastes or chemicals are anticipated to be spread or spilled that would cause significant groundwater contamination. Chemical applications can be high in agriculturally - dominated landscapes and the conversion of the site to urban uses will ensure greater groundwater protection by: (1) covering exposed soils with turf and landscape plants; (2) reducing chemical usage on the site to include only household quantities; (3) providing vegetated infiltration area such as 56.0 acres of park, woodland, and open space and retaining upwards of 55 acres of wetland; (4) providing adequate stormwater treatment systems; (5) abandoning old septic systems and wells, and (6) not drilling new wells for the project. b. Soils and topography - Describe the soils on the site, giving NRCS (SCS) classifications and descriptions, including limitations ofsoils. Describe topography, any special site conditions relating to erosion potential, soil stability or other soils limitations, such as steep slopes, highly permeable soils. Provide estimated volume and acreage of soil excavation and/or grading. Discuss impacts from project activities (distinguish between construction and operational activities) related to soils and topography. Identify measures during and after project construction to address soil limitations including stabilization, soil corrections or other measures. Erosion/sedimentation control related to stormwater runoff should be addressed in response to Item 11. b. ii. The Soil Survey Geographic (SSURGO) digital database for Dakota County (USDA NRCS, Accessed 2014) indicates the soils that occur within the project area (Exhibit 8) are classified as summarized in Table 10.1. Soils on the site are predominantly fine sand and non-hydric loamy fine sands. An area through the north -central section of the Project, and along the southeast and northeast borders, are classified as all hydric and predominantly hydric muck and fine sand soil units. Table 10.1. Soils Classification Map Hydric1 Hydricl Prime Symbol Soil Classification Percent of Category Farmland' Map Unit 541 Rifle muck 100 All hydric Not Prime Farmland 1813B Lino variant loamy fine sand 2-6% 0 Non-hydric Farmland of Statewide slopes Importance 11