Orono_Route_Permit_Application - Docket # W002/TL-11-223

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oak. According to the Department of Soil Science, University of Minnesota, the subsection is predominately characterized as cropland, pasture, upland forest and wetland (Dept. of Soil Science, Univ. of Minnesota 1973, 1980b, 1981a). Croplands and pasture lands are more predominate to the west of the Project than in the immediate area of the Project. Further, urban and rural residential development account for the majority of lands near the Project to the east and south. 6.1.1 Topography Unlike other portions of Minnesota, the Project location was not covered by the most recent glaciations (i.e., 10,500 years before present) (Minnesota River Basin Data Center, 2010). However, melt waters and glacial lakes associated with the last glacial advance contributed large volumes of meltwater to rivers that cut deep valleys along the present course of the Minnesota, Crow, and lower Mississippi Rivers located east, north and south of the Project. The Project is within a Big Woods subsection, which contains broad level areas between hills with closed depressions containing lakes and peat bogs. The surface water drainage network is young and undeveloped, and extensive areas of wetlands are present. Drainage is often controlled by lake levels. Prior to settlement, the area consisted of forest lands and wetlands. Today the topography of the area is level to gently rolling and has been greatly altered from pre - settlement times by residential development, roadways and interchanges, railroad and other man- made features. In general, the elevation within the Project ranges from 964 feet above sea level in wetland areas to 983 feet above sea level at the Orono Substation. Mitigative Measures The Project requires grading the area of the new substation site and storm water management to accommodate the substation replacement (see Appendix B, Figure B-10). To mitigate this, the preliminary design and site layout takes into account existing facilities, wetlands on the north and east sides of the parcel, storm water runoff and management, and surrounding land uses. To the extent possible, Xcel Energy will reuse the existing substation area and avoid wetlands at the site. While the western portion of the site will require grading and a new storm water pond will be installed at the northwest corner of the new substation area, the Project will not change the character of the landscape of the surrounding area. 6.1.2 Geology and Soils The Project site geology is composed of a gently rolling landscape and wetlands. The underlying geology and topography has remained consistent over time. However, the surface topography and natural drainage ways have been impacted by human settlement. Depth of bedrock varies from 100 to 400 feet (Olsen and Mossler 1982) The Project Area is underlain by Cambrian sandstones. The area north of US Highway 12 (Baker Park Reserve) has remained relatively undeveloped as have many of the wetland complexes in the area. Soils throughout the area are predominantly poorly drained hydric wetland soils that are derived primarily from till. Based on the Soil Survey of Hennepin County (U.S. Department of Agriculture ("USDA"), 2000), the most predominant soils in the Project location include the following two soil associations: Orono Project June 7, 2011 MPUC Docket No. E002/TL-11-223 39