6.1. SR 03-17-2003 - Laserfiche WebLink

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ran~ng from 950 in the northern part of the district to 925 at the southern margin. The thickness of unsaturated sand and gravel ranges between 40 and 70 feet. The water table aquifer is approximately 30 feet thick throughout the mining district." "Various other sand and gravel units are present beneath the water table aquifer. The first confined glacial aquifer beneath the water table aquifer occurs at a general elevation of 860 NGVD with a variable thickness of between 20 and 80 feet. This unit is utilized as the primary water supply for residential developments west of the district. Other deeper glacial aquifers are also present but are limited in thickness. The Mt. Simon-Hinckley formations combine to form one confined aquifer and together are generally 150 feet thick. There are no significant aquifer units beneath the Mt. Simon-Hinckley aquifer." "The esker complex contains numerous depressions both natural and man-made that influence the shallow groundwater flow system. The sand and gravel surficial material is conducive to the rapid infiltration of precipitation and surface water depression storage into the water table. Accordingly, standing water in these areas frequently represents a surface expression of the water table. The flow patterns of the water table aquifer are primarily controlled by recharge and discharge, surface topography and the relative · permeability of the shallow geologic materials in the area. Shallow groundwater discharge likely occurs at springs near the base of slopes or into topographically low streams or wetlands." Describe measures to avoid or minimize environmental problems due to any of these hazards. General measures for minimizing risk to groundwater are noted below. Describe the soils on the site, giving NRCS (SCS) classifications, if known. Discuss soil granularity and potential for groundwater contamination from wastes or chemicals spread or spilled onto the soils. Discuss any mitigation measures to prevent such contamination. The following is a listing of the Site soils as identified in the Soil Survey of Sherburne County, Minnesota, dated May 1998 (Soil Survey). A map depicting the numbered units is included as Figure 8 in Appendix A. 158B Zimmerman fine sand 3 to 6% slopes 158E Zimmerman fine sand 12 to 25% slopes 162 Lino loamy fine sand 0 to 2% slopes 540 Seelyeville muck 0 to 1% slopes 730B Sanburn fine sandy loam 2 to 6% slopes 1109 Isanti loamy fine sand 0 to 2% slopes 1253B Stonelake-Sanburn Complex 1 to 6% slopes 1253C Stonelake-Sanburn Complex 6 to 15% slopes 1253E Stonelake-Sanbum Complex 15 to 40% slopes 1254 Rice Lake fine sandy loam 0 to 3% slopes 1260E Stonelake-Nebish Complex 12 to 25% slopes LIESCH ASSOCIATES, INC. Hydrogeologists · Engineers · Environmental Scientists · Jan-2003 - · Page 14 ·