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through alternating clays and sands to a depth of 250 feet or more before intentionally extracting water ( i .e . Y California Water Service wells TINR6E 2M and Q) . Drillers logs of the area indicate the surface clays extend to depths ranging from 50 feet to 27 feet in Section 2 and 3 ` TINR6E MDB & M, before reaching a coarser material that is saturated (DWR Central District data ) . The closest surface stream to the site is Mormon Slough, one mile to the south . The piezometric level of groundwater has been reported to be between 40 and 50 feet below the surface at the site - ( San Joaquin County Flood Control and Water Conservation District, 1988 data ) . However, poor quality first water is probably encountered within 35 feet of the surface (estimate based on driller ' s logs ) . Municipal wells" seal off the first 250 feet because the upper zones of saturation do not meet quality standards or do not provide sufficient quantity to be developed (Bulletin 146, California Department of Water Resources, 1967 ) . Therefore, +w it is highly unlikely the fuel components at this site have affected or will affect drinking water supplies . 2 . 7 Proximity of private, municipal and irrigation wells : The municipal water wells operated by California Water Service Company and mentioned above are in the same section `' but are not on or close to the site under investigation . Furthermore, the wells are sealed to a depth of 250 feet or more . well locations within a one-half ralle radius have been requested from the Department of Water Resources (DWR) . There is not a well on the subject property. Also, no dry wells or septic systems are present on the property. LN 2 . 8 Proposed sampling locations and methodology: The sampling rationale is as follows . This site has fine- textured soils with associated high ion exchange capacities, �.. therefore the lead is expected to have adsorbed onto the soil and not penetrated very deeply. In contrast, the volatile organic fractions of gasoline would be more mobile than lead . Therefore, utilizing the presence or absence of the volatile petroleum hydrocarbons for contamination indication should be sufficiently conservative to delineate the lead contaminated zone at the site . Confirmation would �~ be provided by the laboratory analyses of the soil samples . To assess the contribution of the former underground tanks LN to soil contamination at the site, WaterWork proposes to drill, log, and sample additional soil borings around the former tank locations as shown on Figure 3 . Although �" 4