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2 . 6 Topography, geology, surface water, depth to groundwater : The site is situated on level terrain underlain by flood basin deposits of Pleistocene and Holocene age that are composed of sediments similar to and probably conformable on underlying deposits of alluvium and Tulare formation . The flood-basin deposits are light-to dark brown and grey clay, with concentrations of salt and alkali . Stream-channel deposits of sand and gravel are also included (Hotchkiss and Balding, 1971 ) . This study will investigate water quality in the "shallow water-bearing zone" of Hotchkiss and Balding ( 1971 ) . Groundwater within this zone occurs less than 10 feet below grade over most of the Tracy area . The flood-plain deposits of the shallow water-bearing zone have well developed soil profiles .and, consequently, poor permeability . The base of the shallow zone is poorly defined and probably is from 5 to 25 feet below land surface . Based on monitoring data from a nearby study, groundwater flow in the shallow water-bearing zone beneath the subject property plant is to the north (American Environmental Management, 1988 ) 2 . 7 Proximity of private, municipal and irrigation wells : Well locations within a one-half mile radius have been requested from the Department of Water Resources ( DWR ) . 2 . 3 Proposed sampling locations and methodology : To assess the lateral and vertical extent of soil and/or groundwater contamination beneath the Sung property, Waterwork proposes to : 1 ) drill a total of five sail borings to characterize near surface soils ; and 2 ) convert three of the soil borings to monitoring wells in order to characterize groundwater quality and the local groundwater flow direction at the site . 2 . 3 . 1 Two soil borings will be drilled to a depth of approximately 20 feet . Three additional soil borings will be drilled to a depth of approximately 30 feet to provide for the installation of the groundwater monitoring wells . Drilling will be conducted by Osterberg and Stewart under C57 license 446670 using a hollow stem auger drill rig . The proposed boring/well locations are plotted on Figure 2 . The wells will be constructed of 2 inch diameter F430 PVC screen/casing and completed as shown on Figure 3 . The soil borings will be abandoned with neat cement .