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ion November 21, 2006 NOA Project Number: E06044B ` 5.3 Soil Lithology Observed Generally, the soil encountered in the boring is similar to the soils reported by the San Joaquin LCounty Soil Survey for the area (USDA, 1992). Table 3 presents the soil log for the soil borings. Table 3. Soil Log On-Site Soils Depth Interval(h) Soil Type Unified Soil Classification 0-3 Light brown,moist,clayey silt ML 3-15 Dark brown,moist,fine silty clay CL 15-25 Brown,moist,clayey silt NIL r 5.4 Discussion of Soil Lithology A visual inspection of the shallow soils from on-site drilling indicates some potential for percolation because of the silty nature of the soils. A percolation test is the best method to determine the suitability of the soils for a septic disposal area. Please see the next section for percolation test results. Generally speaking, coarser-grained soils have much greater potential for percolation than fine-grained or cemented soils. 6.0 PERCOLATION TEST INFORMATION 6.1 Percolation Test Locations LA site map indicating the locations of the percolation test holes is included as Plate 1 in the appendix of this report. 6.2 Number of Percolation Tests On shallow an"or deep percolation test was conducted on each parcel. A total of three shallow percolation tests and three deep tests were conducted on the property. 6.3 Boring Preparation and Presaturation One hall�o and ne deep il boring were drilled on each parcel. The three shallow holes were advanc n the si with four inch hand augur on October 25, 2006.The deep borings were ' L advanced on the site with a truck-mounted deep rock augur rig. A 1.5-inch diameter PVC pipe with perforations on the bottom was used to measure the drop of Lwater in the percolation test boring. Approximately 2 inches of"pea gravel" were placed in the 6 L -404 L