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s L! `/ In KLEINFELDER Control and Water Conservation District show groundwater levels in the project area ranging from about 65 to 95 feet below ground surface from Spring 1981 to Spring 1999. FIELD EXPLORATIONS AND TESTING The subsurface conditions at the site were explored on November 19, 2002, by drilling one boring to a depth of approximateIX 9 feet below existing grade_ The boring was drilled using a truck-mounted drill rig equipped with 4-inch O.D. solid-stem auger. During the same time period, percolation borings were drilled to depths of about 3.0 to 3.5 feet below site grade. The approximate percolation test locations are presented on the attached plate. Based on our findings, the subsurface soils encountered consisted of brown to light brown silty sand to a depth of about 8.5 feet below site grade. These soils were underlain by "hardpan" composed of red brown, weakly cemented, silty sand to the depths explored. The percolation tests were performed on November 21, 2002 in accordance with accepted guidelines using clear potable water. The procedure calls for rst placing about 2 inches of fine gravel at the bottom of the borehole. The hole is then pre-soaked with water at least 24 hours prior to performing the test. The test is performed by adding approximately 6 inches of water above the gravel in the hole. From a fixed reference point, 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. Under the observation of a sanitarian from the SJC/EHD, 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 SJC/EHD is attached. uring the inspection, the units of the drop in water were mistakenly recorded_ inches rap 3 than in feet by the sanitarian from SJC/EHD. Per our conversation with Mr. Johnny Yoakum on November 22, 2002, it was acknowledged that the units of the drop m water are indeed feet. The results presented in the following table are based on a water drop recorded in feet. As previously stated, at the time of our investigation the site had recently been 11 ed. To prevent loose soil from falling in the hole, approximately 4 to 6 inches of loose soil was removed from around each hole. As a result, the hole depths shown on several of the field percolation sheets are less than the specified 36 to 42 inchQI, The approximate depth from original site grade of each percolation hole is shown in the following table. Test Number Depth, ft. Percolation Rate (min./inch) P-1 3.0 6O P-2 3.0 5.2 P-3 3.5 7.6 P-4 3.0 9.3 P-5 3.5 15.6 P-6 3.5 5.7 23814.GO1/ST02R814 November 25,2002 ©2002 Kleinfelder,Inc. Page 2 of 4