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.. • ..•........ ..... . . rnn ViiVVo/vu0 key to the Log of Borings is presented on Plate 5 and the Logs of Borings are presented on Plates 6 through 9. Following completion of the soil profile borings, percolation test holes P-1 through P••8 were installed within the proposed parcel area at depths ranging from approximately 3 to 12 feet below site grade. The approximate percolation test hole locations are presented on Plate 2. Following drilling, the sides of the test holes were scored, and significant loose material removed from the bottom of the holes. The percolation test holes were then prepared by first placing about 2 inches of fine gravel at the bottom of the holes and installing a 4-inch diameter, perforated PVC pipe. Before noon on June 8, 2006, about 12 inches of water was placed in the holes for pre-soaking. On June 9, /2006, the percolation tests were started at about 7:30 AM in accordance with SJCEHD accepted guidelines, using clear potable water. None of the holes exhibited sloughing or caving. The holes all contained water prior to testing. From a fixed reference point (a marked location on the side of PVC pipe), the drop in water level was measured in approximate 30-minute intervals for 1'1z to 2 hours (SJCEHD Procedure #2). The percolation tests were terminated after only two hours because the test holes exhibited very little or no percolation. Copies of our field percolation test results are attached on Plates A-10 through A-13. On June 20, 2006, samples of groundwater were obtained using clean procedures from a spigot at the head an agricultural well located on adjacent property west of the subject parcels. A permit for the well was not on file with SJCEHD. The water samples obtained from the well were delivered to a laboratory on ice that same day using chain-of-custody procedures for DBCP and nitrate (N) testing. The boring and percolation test holes were located in the field by visual sighting and/or pacing from existing site features. therefore, the locations shown on Plate 2 should be considered approximate S. GROUNDWATER (/Groundwater was not encountered in our soil profile borings drilled for this investigation. Lines of Equal Depth to Groundwater contour maps published in groundwater reports by the San Joaquin County Flood Control and Water Conservation District (1982 to 1999) show groundwater levels in the project area ranging from about 160 to 180 feet below ground surface. Based on Lines of Equal Elevation of Groundwater contour maps, the groundwater gradient in the project area is generally from east to west. Local gradient variations may occur due to well usage. At the time of our field investigation, two agricultural wells were located along the west side of parcel 009-170-04. No new wells are planned to be constructed within the project area. 57556.G011ST05R687R August 25.2005 ra 2005 Klemlelder,Inc. Pape 2 al 5