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rThe proposed disposal site has level terrain; consequently,there will be no need to incorporate design onsiderations for slopes. Under EHD requirements and regulations, a mound system for effluent isposal would not be allowed for future disposal even though tight silty surface soils exist. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS V The United States Department of Agriculture - Soil Conservation Service (USDA-SCS) indicates the majority of the property soils are Tokay fine sandy loam(#256). The soils near the southeast corner of the subject property are Tujunga loamy sands (#259). The Soil Survey of San Joaquin County states that permeability is rapid-to-moderately rapid in these two soil types, which was not necessarily observed in the 42 inches of soil by the percolation tests conducted. As referenced, the deeper soils below five feet appear to possess permeability. SSS§5.2. The surface and subsurface soil investigation began on May 30, 2008 with the drilling of four percolation test borings and a 35 feet deep exploratory boring with a truck-mounted drill rig and solid stem auger. The exploratory boring was drilled to the 35-foot depth to investigate for saturated soil conditions between 25 feet and 35 feet in depth. The S.J.C. Sewage Standards prohibits saturated soil conditions within 10 feet of a maximum seepage pit depth of 25 feet. The exploratory boring was drilled near the east end of the disposal area as illustrated on the Domestic Waste Site Plan found in Appendix C,while a shallow and a deep perc test boring was drilled at the east side and west side of the disposal area. These test locations were chosen to give a relatively accurate representation of the underlying soil characteristics since this entire disposal area is proposed to be installed with leachlines and seepage pits. ,/NILS§ 1.1, 1.2. Soil cutting samples from the 35-foot exploratory test boring were retrieved from every five-foot depth for physical and chemical analysis. As the noted on the A&L Laboratory Soil Analysis Reports in Appendix B, chemical analyses of the seven soil samples quantify several constituents that will influence nitrate-nitrogen loading potential from this project. The important parameters for nitrate loading assessment are the organic matter,pH, cation exchange capacity (CEC), clay content percentage, along with nitrate-nitrogen content of the soil. As noted, the organic matter is consistently low concentration throughout the soil profile. It was anticipated that the soils would be higher in organics since organic matter from the wine making process has been stored in this area in the past. The nitrate-nitrogen concentration is medium at the 5-ft depth at 15 ppm, then decreases to 6 ppm at the 10-ft depth. At the 15 and 20 ft depths, there are substantial decreases in nitrate-nitrogen concentration at these deeper depths to 2 ppm indicating denitrification potential. Interestingly, the soil nitrate-nitrogen concentration increases to 9 ppm at the 25-ft depth where the soil changes from a sandy clay loam to a sandy loam. The larger porosity of the sandy loam may have influence on nitrification at this depth. Because septic effluent is composed predominately of ammonium(NIIJ, the pH, along with the CEC, are significant influences on ammonium molecules. The pH of the soil profile is slightly alkaline and may not have an effect on ammonium formation and stability. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. Cation Exchange Capacities of the soil samples are comparatively low. This suggests there is a low-to-medium potential for the retention of ammonium molecules for microbial uptake. 3 Chesney Consulting