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05 July 2002 • AGE-NC Project No. 98-0520 Page 4 of 7 2.3. WELL HEAD'SURVEY ' _ a On 05 March 2002, a California state licensed survey engineer from Baumbach & Piazza, Inc. surveyed the elevation of a reference point on the top of ground water monitoring well MW-7 to the nearest 0.01-foot relative to City of Manteca Bench Mark # 63 at 33.758 feet above mean sea level (MSL). The results of the monitoring well survey are contained in Table 1. The surveying report (Baumbach &Piazza, Inc.) is presented in Appendix D. ' 3.0. FINDINGS Soil.'description and ground water elevation and flow direction were determined from field data. Hydrocarbon-impact to soil and ground water was inferred from laboratory analysis of the soil and ground water samples. 3.1. SOIL PROFILE ' • A general `subsurface soil profile at MW-7 was developed from the well-log soil description, supplemented by boring logs from the AGE-prepared Preliminary Investigation and Evaluation Report, Quarterly Report - Fourth Quarter 1999, dated 25 April 2000, and Quarterly Report - ' Fourth Quarter 2001, dated 27 June 2002. The upper 16 feet consisted of yellowish to brownish green, generally unconsolidated, fine to medium sand. Between 16 and 35 feet bsg was a fine-grained interval consisting of yellowish to olive green clay with silt/silty clay/clayey fine sand, interbedded with thinner, olive green medium ' sand layers. Below 35 feet bsg the.soil consisted of olive green, unconsolidated medium sand. A geologic cross,section is provided in Figure 3, and a boring log is provided in Appendix A. r 3.2. FIELD EVIDENCE OF HYDROCARBON-IMPACTED SOIL Org anic vapor was not detected above background in soil sample duplicates by the OVM; likewise, petroleum hydrocarbon-like odor was not detected in the "soil sample duplicates. The PID data is included on the boring logs (Appendix A). ' Advanced GeoEnvironmentel,Inc.