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12958/12970 E Jahant Road Project No. 2022-00037 P a g e 13 The surface and near surface soils located at the site are reported by the San Joaquin County Soil Surveys to be composed of the 112 Bruella sandy loam with a hard substratum (Plate 4, Appendix A). The Bruella loam consists of alluvium formed of primarily granitic sources. This soil is moderately well drained according to San Joaquin County Soil Survey4. The permeability is slow in the hard substratum of the Bruella soil, and it is moderately slow in the upper portion of the soil. The water table is typically more than 6 feet deep, but water may be briefly perched above the hard substratum after periods of heavy rainfall or irrigation. Table 1. San Joaquin County Soil Survey Elected Soil Properties of On -Site Soils Soil Name Depth p Salinity Soil Perme- aic Stank nd Map (in) Unified Soil Classification mmhos/ Reaction ability o an Symbol cm pH (in/hr) fields 0-8 Sandy loam (SC -SM, SM) <2 6.1-7.3 2.0-6.0 <2 Moderate Bruella 8 42 Sandy loam, Sandy Clay 6.1-7.3 0.2-0.6 wetness Loam 112 loam (SC) very slow perc 42-60 Sandy 9Y loam SC <2 6.1-7.3 1 0.06-0.2 Note: The table descriptions do not necessarily reflect site-specific soil properties. * See description of the map unit for composition and behavior characteristics of the map unit 3.2 Mass Transport Soil Properties Sandy loam, sandy clay loam, and fine sandy loam such as the fine-grained soil layers reported for the Bruella soil at the site typically provide a moderate degree of protection between percolating effluent at the surface and ground water aquifers. Therefore, soils of this type typically present a moderate risk of excessive mass transport of nitrate or other constituents of concern. 4.0 GROUNDWATER INFORMATION 4.1 Groundwater Depth and Gradient The San Joaquin County Flood Control and Water Conservation District (2021) groundwater reports were reviewed to determine the groundwater levels near the Site. The Fall 2021 and Spring 2021 maps (Plate 5 and 6, Appendix A) are the most current official maps available from the County. According to the groundwater reports, the groundwater elevation is approximately -40 feet below the mean sea level (msl) in the spring and -45 feet msl in the fall. The land elevation of the site is approximately 115 feet above mean sea level. Therefore, the depth to groundwater (the difference between the elevation of the Site and the elevation of groundwater), is approximately 160 to 155 feet below the ground surface (bgs). The groundwater in the area appears to flow to the north towards a cone of depression. The groundwater gradient is approximately 5 feet per mile. 5 United States Department of Agriculture. Soil Survey of San Joaquin County, California. October 1992. Petralogix Engineering, Inc. 26675 Bruella Road, Galt. Ca 95632 (209)-400-5729 www.petralogix.com