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Attachment A The topography varies from 914 to 930 feetin elevation across the site. The steepest slopes are about 1:3 and are located on the outer north and east edges of the property. Temporary stabilization measures such as erosion control blankets will be used on disturbed steep slopes to prevent erosion and sedimentation of the adjacent ditches during construction. Vegetation establishment will be used to permanently stabilize and disturbed side slopes. The south side of the site will be close to balancing earthwork, while the north side of the site will require between 50,000-100,000 cubic yards of excavation due to underground parking. The cut soil may be used for ditch improvements to the west and north of the site. Note: For silica sand projects, the EAW must include a hydrogeologic investigation assessing the potential groundwater and surface water effects and geologic conditions that could create an increased risk of potentially significant effects on groundwater and surface water. Descriptions of water resources and potential effects from the project in EAW Item 11 mustbe consistent with the geology, soils, and topography/land forms and potential effects described in EAW Item 10. 11.Water Resources a.Describe surface water and groundwater features on or near the site below. i.Surface Water –lakes, streams, wetlands, intermittent channels, and county/judicial ditches. Include any special designations such as public waters, trout stream/lake, wildlife lakes, migratory waterfowl feeding/resting lake, and outstanding resource value water. Include water quality impairments or special designations listed on the current MPCA 303d Impaired Waters List that are within one mile of the project. Include DNR Public Waters Inventory number(s), if any. No surface water resources (wetlands, lakes, streams, etc.) are located within the project site. A ditch is located along the northern and eastern edges of the project site. Within one mile of the sitethere are 12 DNR public water wetlands, twoDNR public water basins, and oneDNR public water watercourse.There are no impaired waterswithin one mile of the project. ii.Groundwater –aquifers, springs, and seeps. Include 1) depth to groundwater; 2) if project is within anMDH well protection area; and 3) identification of any onsite and/or nearby wells, including unique numbers and well logs, if available. If there are no wells known on site or nearby, explain the methodology used to determine this. The project is not within a wellhead protection area or drinking water supply management area. According to the Phase I ESA, two monitoring wells are locatedwithin the project site (seeTable 6). If any additional wells are encountered during construction, they will be capped and sealed according to the Minnesota Department of Health regulations. The depth to groundwater in this area is approximately 25 to 30 feet. Twin Lakes Station9 March 2020