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KLEINFELDER GROUNDWATER DEPTH During the time of our investi ation, groundwater was not tered. Lines of Equal Depth to oundwater contour maps published-in group water reports by the San Joaquin County Flood Control and Water Conservation District show groundwater levels in the project area ranging from about 55 to 60 feet below ground surface from Spring 1995 to Spring 1999. FIELD EXPLORATIONS AND TESTING The subsurface conditions at the site were explored on December 19, 2002, by drilling one boring to a depth of approximately 8 feet below exist_�ade. The boring was drilled using a truck-mounted drill ng equippe wi -mc O.D. solid-stem auger. During the same time period, percolation borings were drilled at each parcel to depths of about 3.5 and 6.5 feet below site grade at locations specified by the client. The approximate percolation test locations are presented on the attached plate. Based on our findings, the subsurface soils encountered consisted of brown silty sand to the depths explored. The percolation tests were performed on December 20, 2002, in accordance with accepted guidelines using clear potable water. The procedure calls for first placing about 2 inches of fine gravel at the bottom of the borehole. The holes were then pre-soaked with water at least 24 hours prior to performing the tests. The tests were performed by adding approximately 6 to 11 inches of water above the gravel in the hole. From a fixed reference point, 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. Under the observation of a sanitarian from the SJC/EHD, the last 30-minute reading of the four hour period was 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. Parcel "Test Number Depth, ft. Percolation Rate " _ (min./inch) North Parcel P-1 3.5 22.7 North Parcel P-2 6.6 14.7 South Parcel P-3 ' 3.9 83.3 South Parcel P-4 10.9 24832.G01/ST03R033 January 3,2003 ©2003 Kleinfelder,Inc. Page 2 of 3