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FA. SUBJECT IL SUITABILITY STUDY FINDINGS PROPERTY AND SURROUNDING STUDY AREA INFORMATION esujecproperty has been in the Harris Family for more than 40 years. The surrounding land use to the north, south, east and west of the project is, and has been, in agricultural production for many decades. This is evidenced by the United States Department of Agriculture(USDA) Soil Maps for San Joaquin County for this area. Applications on file with the County Environmental Health Department reveal that there have been three permits issued for additions to existing systems, and no permits for repairs in the one mile study area. The fact that there has been no repairs can be attributable to the sandy soil structure existing at typical leachline depths and extending to an intermittent hardpan layer at approximately 10 ft below grade. B. SOIL PHYSICAL AND CHEMICAL CHARACTERISTICS 1. SURFACE AND SUBSURFACE SOILS The project site has level terrain; consequently, there will be no need to incorporate design considerations for slopes. The United States Department of Agriculture -Natural Resources ` Conservation Service(USDA-NRCS)indicates the on-site soils to consist mostly of Delhi loamy sand(#142), followed in order of total land area within the project by Tinnin loamy coarse sand (#255), Honcut sandy loam (#175) and Veritas fine sandy loam(#266). These soil units correlate with the following soil texture test results as noted on the SOIL ANALYSIS REPORT: -82% sand, -5% silt and -13%clay. The Unified Soil Classification System(USCS) identifies this soil as a silty sand (SM). According to the USDA Handbook,the main limitation with these �- soils are the rapid permeability in the substratum, which is evidenced by the percolation test results. However, there is also sufficient fine material (clay and silt sized particles)to promote biological treatment of the effluent before reaching the water table (-28 ft below grade). Biological treatment includes the destruction of bacteria and viruses. Particle Size Analysis of the on-site soils are illustrated on the SOIL ANALYSIS REPORT indicate the soils possess approximately 18%clay and silt. A 10-ft hand boring was completed in the middle of Parcel 1. This boring provided 1.) a profile ` of the underlying soil characteristics,2.)hardpan layer determination and 3.) subsurface soil hydraulic conductivity. The log of boring illustrates the subsurface soil characteristics encountered: The surface soils to 5 feet consist of a light brown silty sand. Below this strata and extending to the boring termination is a coarser silty sand. At approximately 10 ft, a tight,hard cemented silts hardpan layer was encountered with a higher moisture content. No rust mottling was observed in the upper soil profile, although there was slight mottling occurring at the deeper depths above the hardpan strata. This is where there would be an impedance to downward water flow. Rust mottling can be indicative of seasonal soil saturation. Rust mottling was observed 2 Va(!ey Ag Research