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5.11:SOILS <br /> The project area includes the proposed LEC project site and linear features (i.e.,overhead <br /> electrical lines and underground gas, sewer and water pipelines). Table 5.11-1 summarizes <br /> depth, texture, drainage,permeability,water runoff, and items related to revegetation <br /> potential. Actual soil conditions in the project area could differ from what is described in the <br /> generalized soil descriptions because of the potential for previous grading at the site and <br /> natural soil variation. For example,Devries is the dominant soil series in map unit 149 <br /> (85%); other soil components occupy up to 15 percent of the map unit, and these soils may <br /> have characteristics that are dissimilar to those described for the map unit. <br /> 5.11.1.1 Agricultural Use <br /> Based on a review of aerial photography, it appears that much of the land immediately <br /> surrounding the proposed LEC project site is used for agricultural production. Based on <br /> observations made during the biological field survey,most of this land was planted with <br /> forage crops (mostly alfalfa);however,it is expected that these fields may also be used at <br /> times for other row and grain crops depending on crop rotation cycles. <br /> 5.11.1.2 Soil Mapping Units <br /> Table 5.11-1 describes the properties of the soil mapping units that are found in the vicinity <br /> of the proposed LEC project site. As shown on Figure 5.11-1,the entire proposed LEC site <br /> and associated facilities lie within the soil mapping unit, 149-Devries sandy loam, drained, <br /> 0 to 2 percent slopes. This soil mapping unit,which would be directly affected by the LEC <br /> project and associated facilities,primarily consists of moderately-coarse to medium textured <br /> soils (sandy loam,fine sandy loam,or loam) in alluvium that is derived from mixed rock <br /> sources. These soils are somewhat poorly drained and have moderately rapid permeability <br /> and slow runoff. <br /> The soil mapping unit mapped immediately to the south of the LEC site and facilities was <br /> 169-Guard clay loam, drained,0 to 2 percent slopes. That soil mapping unit,which should <br /> not be directly affected by the proposed LEC project,consists primarily of moderately fine <br /> textured soils (clay loam) in alluvium that is derived from mixed rock sources. These soils <br /> are poorly drained and have slow permeability and slow runoff. <br /> 5.11.1.3 Potential for Soil Loss and Erosion <br /> The factors that have the largest effect on soil loss include long, steep slopes;lack of <br /> vegetation;and erodible soils with high proportions of silts and very fine sands. The soils <br /> found in the proposed LEC project area are nearly level,with an estimated average slope of <br /> less than two percent. <br /> In general, soils at the proposed LEC project site are of moderately coarse to medium <br /> texture above the indurated hardpan,ranging from sandy or fine sandy loam to loam <br /> (NRCS,1992). The erosion potential of these soils will vary,based on the wetness of the soil, <br /> soil compaction,sizes of soil particles,and other site-specific properties. Based on the soil <br /> survey information,the soils at the proposed LEC project site are expected to have slight <br /> water erosion potential and a moderate wind erosion potential. <br /> It should be noted that given the historical filling and grading for the WPCF soil conditions <br /> at the proposed LEC project site may not be the same as those that have been mapped in the <br /> soil survey. The onsite soils could be imported soils of construction fill which,if exposed, <br /> SACI371322I082330009(LEC_5.11_SOILS.DOC) 5.11-5 <br />