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Soil Suitability/Nitrate Loading Study Irerracon <br /> Pickens Property ■ Tracy, California <br /> May 12, 2020 ■ Terracon Project No. NA207032 <br /> Terracon reviewed the United States Department of Agriculture (USDA) Natural Resources <br /> Conversation Service (NRCS) Web Soil Survey and USDA Soil Survey of San Joaquin County <br /> (1992) for information regarding soil properties. Based on information obtained from the USDA <br /> sources, the site consists of Capay clay soils with 0 to 1 percent slopes. Parent material is clayey <br /> alluvium derived from sedimentary rock. Typical soil profiles consist of 0 to 60 inches clay. Capay <br /> clay soils are moderately well drained with high runoff potential, slow permeability, and high shrink <br /> swell potential. For sites with septic systems, permeability can be improved by increasing the size <br /> of the absorption field, backfilling leachfield trenches with sandy material, and installing long <br /> absorption lines. <br /> 1.5.1 Soil Boring Locations <br /> Based on a review of the site plan,the proposed leach field will be located east of the new modular <br /> home, therefore, one percolation test boring (B3.5) and a 10 foot deept soil profile (610) were <br /> placed near the anticipated leach field. Refer to Appendix A, Exhibit 2 for the approximate boring <br /> locations. It should be noted Terracon conducted the percolation test field work for the site in <br /> 2018. Refer to Appendix E. Percolation Test Letter dated August 14, 2018 (Terracon Project No. <br /> NA181172). <br /> 1 .5.2 Soil Boring Dimensions <br /> Soil borings were advanced with a 4-inch diameter hand auger. Boring B3.5 was advanced to <br /> 3.5 feet bgs and boring B10 was advanced 10.0 feet bgs. <br /> 1 .5.3 Soil Lithology Observed <br /> The following table presents a log of the soil boring(s). <br /> Table 5. <br /> Summary of Soil Lithology <br /> Boring Depth Soil Type Unified Soil <br /> Interval(ft) Classification <br /> 0-1.8 Trace clay, high dry strength, high toughness, dark brown dry SW-SC <br /> B3.5 Trace calcareous nodules, nonplastic, low dry strength, low <br /> 1.8-3.5 toughness, tannish brown, silty fine sand to a fine sandy silt with clay. SW-SC <br /> Soils at 3.5 feet are somewhat tight silty fine sand with traces of clay <br /> 0-1.8 Trace clay, high dry strength, high toughness, dark brown dry SW-SC <br /> ------- ----------- — ------------------------ -- --- <br /> B10 Trace calcareous nodules, nonplastic, low dry strength,tannish <br /> 1.8–10.0 brown, silty fine sand to a fine sandy silt with clay. SW-SC <br /> Responsive■ Resourceful ■ Reliable 9 <br />