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Pearson Farm Residential Development EAW Draft — March XX, 2017 <br />Sinkholes and karst lands are not known to occur in western Anoka County where the project is <br />located. Minnesota Karst Lands and Sinkhole Mapping prepared by Calvin Alexander and others <br />(2006) does not shows karst lands or sinkholes in or near the project area. <br />b. Soils and topography - Describe the soils on the site, giving NRCS (SCS) classifications and descriptions, <br />including limitations of soils. Describe topography, any special site conditions relating to erosion <br />potential, soil stability or other soils limitations, such as steep slopes, highly permeable soils. Provide <br />estimated volume and acreage of soil excavation and/or grading. Discuss impacts from project activities <br />(distinguish between construction and operational activities) related to soils and topography. Identi <br />measures during and after project construction to address soil limitations including stabilization, soil <br />corrections or other measures. Erosion/sedimentation control related to stormwater runoff should be <br />addressed in response to Item 11. b. ii. <br />The Web Soil Survey indicates the project area includes five soil mapping units that consist of <br />mostly loamy sands (Table 4, Figure 9). <br />Table 4. Soil Classifications <br />Symbol Soil Name <br />D2OA Isan-Isan, frequently ponded, <br />complex, 0-2% slopes <br />D67A Hubbard loamy sand, Mississippi <br />River Valley, 0-2% slopes <br />D67B Hubbard loamy sand, Mississippi <br />River Valley, 2-6% slopes <br />D67C Hubbard loamy sand, Mississippi <br />River Valley, 6-12% slopes <br />Dp Duelm loamy sand, 0-2% slopes <br />% of % <br />Area Hydric <br />8.1 95 <br />55.1 1 <br />5.7 3 <br />13.4 0 <br />17.7 7 <br />Hydric Category Farmland Category <br />Not prime farmland <br />Not prime farmland <br />Not prime farmland <br />Non-hydric Not prime farmland <br />Not prime farmland <br />Predominantly <br />hydric <br />Predominantly <br />non-hydric <br />Predominantly <br />non-hydric <br />Predominantly <br />non-hydric <br />These soils have varying levels of limitations for dwelling units and local streets due to factors such <br />as depth to saturated zone, frost action, ponding, and slope. Depth to saturation limitations are often <br />associated with wetlands, which are addressed under Item 11.a.i below. Soils in the project area are <br />generally considered slightly to moderately susceptible to the sheet and rill erosion by water, as <br />indicated by slopes and K factors that range between 0.0 and 0.50. <br />Grading operations for residential development construction are expected to affect about 87 acres <br />and involve movement of about 475,000 cubic yards of soil to construct streets, residential building <br />pads, and stormwater features. Grading is expected to avoid disturbance of wetlands and trees that <br />will be preserved, which cover about two acres within the project area. <br />Elevations in the project area range from 887 feet above mean sea level at the highest point in the <br />northeast part of the project to 868 feet at the lowest onsite wetland. Review of two -foot contour <br />mapping indicates the site has less than an acre of slopes that equal or exceed 12% and the site does <br />not include any bluffs. Soils mapping does not classify any parts of site as having slopes of 12% or <br />more (Table 4, Figure 9). <br />9 <br />