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A review of Application Permits on file with the San Joaquin County Environmental Health Department indicates there have been nine Applications for Repairs/Additions in the one mile radius study area. These system modification applications were for additional leachlines, sumps and pits. Three well logs from nearby wells are also attached which illustrate the deep subsurface soil strata. [3] PROPOSED DEVELOPMENT OF THE SUBJECT SITE As referenced, it is proposed to adjust the lot line between APN 09&23 to create the 3.0 acre Parcel 1 and divide the remainder of Parcel 23 into four Parcels. It is our understanding there is to be a single family residence built on Parcel 1. All related septic system structures and the domestic well for this structure will have to comply with the published "distance" requirements found in the San Joaquin County Sewage Standards. [4] SOIL PROFILE AND PERCOLATION TESTING The predominate soil type from grade to 4 feet is a silty clay with a high organic matter content. Below this stratum, is a reddish brown, clayey silt. A hardpan layer was not encountered in the drilling procedures. It is important to note that the soil on proposed Parcels 1, 2, 3 and 4 were recently ripped down to six feet. The attached Water Well Drillers Report indicate intermittent strata of clay and gravel to over 200 feet in depth. Each of the six perc test borings were set at four feet below existing grade to test for effluent percolation or the "wetting front" that will occur in native soil. Our percolation tests were conducted according to San Joaquin County Department of Environmental Health regulations. From the attached perc test results, it was determined this four foot depth produces acceptable percolation rates. Although the indigenous soils are clay,these relatively fast perc rates can be attributed to two factors. First, as referenced, part of the land was recently ripped. This opens the soil structure and creates both macroscopic and microscopic channels for water flow. Secondly, it had recently rained prior to our perc tests. Some clay soils possess the capability of increased percolative capacity when wet. This is due to the fact that water has a great affinity for itself and individual water molecules "pull" themselves through the microscopic pores of the clay soil. Due to the favorable perc rates at the shallow depths, deeper perc tests were not performed. From previous explorations in the area, sand and gravel strata exist within 25 ft of the surface. A discussion of the perc rates, and septic system design recommendations will follow in the Conclusions section of this report. Valley Ag Prsearck