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�� KLEINFELDER Based on the Soil Survey of San Joaquin County, California published by the U.S. Department of Agriculture, Soil Conservation Service (1992), the soils vary within the study area. The soil series and attributes mapped at the site are given in the table below: Map Percolation Available Water Organic Symbols Soil Name CharacteristicsCapacity, PH Content, inches/inch Percent 130 Columbia Moderate 0.08-0.12 6.1-7.8 0.5-2 (flooding, peres slowly) 166 Grangeville Moderate 0.08-0.14 6.6-8.4 1-6 (flooding, wetness) 197 Merritt Severe 0.11-0.19 6.6-8.4 1-4 ( eres slowly) 133 Ryde Severe 0.17-0.25 5.1-7.8 2-10 (wetness) 6. PERCOLATION TESTING Percolation test holes were installed at each of the proposed parcels using the same drill rig as used for the soil profile borings only equipped with a 6-inch diameter auger. The approximate percolation test locations are presented on Plate 1. Following drilling, the sides of the holes were scored, and significant loose material was removed from the bottom of each hole. The holes were drilled and prepared before noon on August 23, 2004, in accordance with SJCEHD criteria. Approximately 2 inches of fine gravel were placed at the bottom of each test hole, and the holes were presoaked with a minimum of 12 inches of water at that time. The percolation tests P-2 and P-3 were started at about 8:00 AM under sunny and warm r weather on August 24, 2004, in accordance with accepted guidelines using clear potable water. Due to rapid percolation in test hole P-1 this test was temporarily discontinued. The approximate depth of each percolation test below existing site grade is shown on the following table. The holes did not exhibit sloughing or caving. At the time of testing, no standing water from the presoaking remained in the holes. From a fixed reference point, a marke ocation on the side of PVC pipe inserted into each hole, the drop in water level was measured in approximately 30-minute intervals for four hours, refilling as necessary to maintain the prescribed amount of water over the gravel (SJCEHD Procedure #2). The last two 30-minute readings were recorded under the observation of a representative from the SJCEHD and were �. used to calculate the percolation rate in minutes per inch. After witnessing the percolation in test holes P-2 and P-3, the SJCEHD representative observed as test hole P-1 was again filled with water at approximately 12:00 PM. Due to the rapid rate of percolation, readings were •• taken at a five-minute interval. The estimated percolation rates for the three tests 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. 48067.G01/ST04R1257 Page 4 of 8 ©2004 Kleinfelder, Inc. September 29,2004 r