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2 . 5 Estimates of liquid quantity and composition of hydrocarbons: <br /> No estimate of the liquid quantity present can be made with <br /> existing information. The constituents detected in the soil <br /> samples appear to be derived from crude petroleum. <br /> 2 . 6 Topography, geology, surface water, depth to groundwater: <br /> The site is situated on level terrain underlain by flood <br /> basin deposits of Pleistocene and Holocene age that are <br /> composed of sediments similar to and probably conformable on <br /> underlying deposits of alluvium and Tulare formation. The <br /> flood-basin deposits are light-to dark brown and grey clay, <br /> with concentrations of salt and alkali. Stream-channel <br /> deposits of sand and gravel are also included (Hotchkiss and <br /> Balding, 1971 ) . <br /> This study will investigate water quality in the "shallow <br /> water-bearing zone" of Hotchkiss and Balding ( 1971 ) . <br /> Groundwater within this zone occurs less than 10 feet below <br /> grade over most of the Tracy area. The flood-plain deposits <br /> of the shallow water-bearing zone have well developed soil <br /> profiles and, consequently, poor permeability. The base of <br /> the shallow :one is poorly defined and probably is from 5 to <br /> 25 feet below land surface. <br /> Based on monitoring data from a nearby study, groundwater <br /> flow in the shallow water-bearing zone beneath the subject <br /> property is to the north (American Environmental Management, <br /> 1988 ) . <br /> 2 . 7 Proximity of private, municipal and irrigation wells: <br /> Well locations within a one-half mile radius have been <br /> requested from the Department of Water Resources (DWR) . <br /> 3 . 0 FIELD INVESTIGATION <br /> 3 . 1 Purpose and Scope/Methods <br /> On June 22, 1989, five surface soil samples were collected <br /> at the project site. Soil sample locations are plotted on <br /> Figure 2 . The samples were analyzed by B.C. Laboratories <br /> ( DOHS certification No. 102 ) for asbestos utilizing EPA <br /> method 600. Asbestos was not present in any of the samples <br /> above method detection limits. The laboratory data sheet <br /> and chain-of-custody documentation are included in Appendix <br /> II . <br /> On July 17 and 18, 1989 two soil borings were advanced to a <br /> depth of approximately 13 . 5 feet below grade. Three <br /> additional soil borings were drilled to a depth of 26. 5 feet <br /> to provide for the installation of groundwater monitoring <br /> 2 <br />