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L..�� hq KLE[ NFELDER Based on our findings, the subsurface soils encountered consisted predominately of sandy silt and silty sand fill soils with minor amounts of debris to a depth of about 9 feet below the existing site grade underlain by interbedded silty and relatively "clean" sand strata to the maximum depth explored. A more detailed description of the subsurface conditions encountered during our field investigation is presented on the attached Log of Boring. In general, the moderately permeable near-surface sand in the project area yields percolation tests passing SJCEHD percolation requirements. The Soil Survey of San Joaquin County, California published by the US Department of Agriculture, Soil Conservation Service (1992) refers to the near-surface soils within the project area as belonging to the Tokay fine sandy loam soil series (Map Symbol 256). The soils are described as having slight percolation characteristics, an available water capacity of 0.12 to 0.14 inches per inch, a pH ranging from 6.1 to 7.8, and an organic content of 1 to 3 percent. PERCOLATION TESTING The 6-inch diameter percolation holes were drilled with the same equipment as the soil profile boring. One percolation hole (in addition to the profile hole) was drilled on the subject property. The holes had scored sides and no significant loose material in the bottom of the hole. All of the holes were drilled and prepared before 8:45 am on September 11, 2003. The preparation procedure calls for first placing about 2 inches of fine gravel at the bottom of the borehole. The hole is then pre-soaked with a minimum of 12 inches of water at least 24 hours prior to performing the test. The percolation tests were started at 11:32 am on September 12, 2003, under sunny and warm weather, in accordance with accepted guidelines using clear potable water. All holes were still intact with no significant sloughing or caving noted. The approximate depth of each percolation test below existing site grade is shown on the following table. The holes were dry prior to testing. From a fixed reference point, a marked location on the side of PVC pipe inserted into the hole, the drop in water level is measured in approximately 30-minute intervals for four hours, refilling as necessary to maintain the prescribed amount of water over the gravel (Procedure 42). Under the observation of a representative from the SJCEHD, the last 30-minute reading of the four-hour period is recorded and used to calculate the percolation rate in minutes per inch. The estimated percolation rates are summarized below. A copy of our field percolation test results signed by a representative from SJCEHD is attached. Details of each test can be found on the percolation test sheet. Test Number Depth, feet Percolation Rate min./inch P-1 3.5 25 14 3 Based on the passing percolation tests and soil types encountered, we do not predict any problems with the proposed septic system or foresee the need for an engineered or alternative septic system. We do not anticipate any geotechnical restrictions on future type, size, or location of any additional leach fields on the subject property. 35025.GO1/STO3R1509 October 10,2003 ©2003 Kleinfelder,Inc. Page 3 of 6