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~ v kn KLEINFELDER — We do not know of groundwater contamination issues at the site at this time. The potential exists for groundwater to be contaminated through the use of pesticides and herbicides. Potential sources of nitrate include fertilizer that may be used in the area, as well as septic usage of the nearby single-family residences. 5. SOIL PROFILE The subsurface conditions at the site were explored before noon on March 18, 2004 by drilling two borings to a depth of about 15 feet below existing grade. The borings were drilled using a Simco 2400 truck-mounted drill rig equipped with 4'/2-inch O.D. solid-stem auger. The approximate location of the test borings and dimensions from a reference point are presented on -� the Plate 1. Based on our findings, the subsurface soils encountered in boring B-1 consisted predominately of moderately plastic sandy clay to a depth of about 7'/z feet below the existing site grade, underlain by silty sand to the maximum depth explored. The silty sand encountered was weakly cemented to a depth of about 12% feet below the existing ground surface. The soils encountered in boring B-2 generally consisted of highly interbedded strata of low- plastic sandy silt, moderately-plastic sandy clay, and fine-grained silty sand to a depth of about 11 feet below the existing site grade, underlain by relatively "clean" sand to the maximum depth explored. More detailed descriptions of the subsurface conditions encountered during our field investigation are presented on the Logs of Borings, Plates 5 and 6. 1/ 6. PERCOLATION TESTING Shallow and deep percolation test holes were installed in each of the proposed parcels with the same rig used to drill 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 the holes. The holes were drilled and prepared before noon on March 18, 2004, in accordance with SJCEHD criteria. Approximately 2 inches of fine gravel was 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 were started at about 10:00 AM under sunny and warm weather on March 19, 2004, in accordance with accepted guidelines using clear potable water. 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, standing water from the presoaking remained in the shallow hole at location P-1 and at the deeper holes at P-2 and P-3. From a fixed reference point, a marked location 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 October 15,2004 42270.G01/ST041383 Page 3 of 6 ©2004 Kleinfelder,Inc.