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FThenderlying material to 60 inches is a yellowish brown gravelly loam. Permeability is rately slow in the Zacharias soil. The Xerofluvents soils are usually on alluvial fans,intermittent stream channels and in areas of gravel tailing deposits. This soil type is very deep and well drained. The surface soil of 20 inches is a brown, very gravelly loam and a gravelly sandy loam. The deeper subsoils to 60 inches are stratified as a pale brown, very gravelly, sandy loam. Permeability is slow to rapid in the Xerofluvents soil. The aforementioned house south of the subject property is located in this soil type, which apparently has not had septic system problems. Effluent that infiltrates and percolates through this fine soil material (clay and silt sized particles) will undergo biological treatment of the effluent before reaching the water table (-150 ft below grade according to the well log). Biological treatment includes the destruction of bacteria and viruses. The surface and subsurface investigation of the property soils under the three Parcels was conducted with a truck-mounted drill rig. A five-inch diameter solid stem auger and a split-spoon sampler were used to drill the percolation test borings and to sample soil at the referenced depths. Perc test drilling began on Parcel 1. After drilling approximately 12 inches below grade through a "top soil"that covers the entire property acreage, severe gravel content was encountered. We were able to drill to a depth of 9.2 feet(110 inches), where auger advancement ceased. This is termed "auger refusal' and is relatively rare in San Joaquin County soils. It typically occurs only in the most heavily graveled or cobbled soil and typically at deeper depths. Refusal was due to the subsoils being highly compact and cemented from silts and clays that were bound by the gravel and cobble content. Two percolation test borings were set on Parcel 1 at 110 inches and 36 inches. Parcel 2 was drilled next. Auger refusal was encountered at 4.7 feet (56 inches), again attributable to high gravel/cobble content, leading to highly consolidated soils. Consequently, the two Perc test borings for this Parcel were set at 56 inches and 36 inches in depth. Severe auger refusal also occurred on Parcel 3 at the 42-inch depth due to the high gravel content. Therefore, the Perc test boring for this Parcel was set at auger advancement termination of 42 inches in depth. Logs of boring for each of the test borings are found on the Percolation Test Forms. Soil classification was conducted by both the USDA and Unified Soil Classification System (USCS). For the USDA soil classification and comparison purposes, soil samples were retrieved from the 9.2 foot boring on Parcel 1 and the 42 inch deep boring on Parcel 3. Gravel was removed from these samples so that an accurate description of the sand, silt and clay contents could be established. The two samples as illustrated on the Soil Analysis Report reveal identical soil structures between the two samples of 46% sand, 26% silt and 28% clay contents. This clay content percentage can be considered comparatively high. The Unified Soil Classification System, with the gravel content included, would be described as a gravelly, silty clay(GC). The top soil over the entire site would be classified as a clay loam (clayey silt: CL-ML). 3 -J Chesney Consulting r,