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� u <br /> June 8, 2006 <br /> NOA Project Number: E06036A <br /> Quaternary Riverbank Formation. Quaternary Riverbank Formation (middle member) is made up <br /> —' of arkosic alluvium which forms Mokelumne River terraces and alluvial fan; chiefly sand;12robably <br /> glacial outwash lower fans (Plate 7). <br /> The surface and near surface soils located at the Site are reported by the San Joaquin County Soil Survey <br /> to be composed of Bruella sandy loam,hard substratum, 0-2% slopes and San Joaquin loam, thick <br /> surface, 0-2% slopes (Plate 8) (USDA, 1992). Table 2 presents some selected properties of these <br /> soils: <br /> Table 2. <br /> San Joaquin County Soil Survey <br /> Selected Soil Properties of On-Site Soils. <br /> Soil Name Depth Unified Soil Classification Salinity Soil Perme- Septic tank <br /> and Map (in) mmhos/cm Reaction ability absorption <br /> Symbol pH (in/hr) fields <br /> Bruella 0-8: Sandy loam;SC-SM,SM <2 6.1 -7.3 2.0-6.0 Severe:peres <br /> sandy loam, 8-42: Sandy loam,sandy clay loam; <2 6.1 -7.3 0.2-0.6 slowly <br /> hard 42-60: SC <2 6.1 -7.3 0.06-0.2 <br /> substratum, Sandy clay loam,sandy clay; <br /> 0-2% SC <br /> slopes, 112. <br /> San Joaquin 0-12 Loam;CL-ML,NEL <2 5.6-6.5 .6-2.0 Severe: <br /> loam,thick 12-26 Sandy clay loam;SC <2 6.1-7.3 .2-.6 cemented <br /> surface, 26-35 Clay loam,clay;CL <2 6.1-7.8 <0.06 pan,peres <br /> 0-2% 35-60 Indurated;-- --- --- --- slowly <br /> slopes,240. <br /> Note:The table descriptions do not necessarily reflect site-specific soil properties. <br /> 5.1 Soil Boring Locations <br /> A total of 8 soil borings were advanced on the Site. Four borings were drilled to a depth of <br /> approximately three to three and a half feet. Four deep borings were drilled to a depth of <br /> approximately 8, 15 , 25 and 27 feet. The soil borings were later used for the percolation test holes; <br /> the locations of the borings are indicated in Plate 1. <br /> 5.2 Soil Boring Dimensions <br /> Four shallow borings were drilled to a depth of about three to three and a half feet. Four deep <br /> borings were drilled to a depth of approximately 8, 15 , 25 and 27 feet, as noted above, and were <br /> four inches in diameter. While drilling the deep tests on parcel two augur refusal was encountered <br /> between 8 and 15 feet due to cemented hard pan mixed with some cobbles. These deep boring <br /> percolation tests were conducted at a depth of 7.82 feet and 14.78 feet. <br /> 5 <br />