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until these parameters stabilize over two measurements, which are interpreted to indicate aquifer water entering the casing. The well was allowed to stabilize to about 80% of its initial water level before sampling. Each groundwater sample was carefully collected with a clean disposable PVC bailer and poured with minimum cavitation and minimum headspace into the appropriate laboratory prepared container. Each water sample was labeled, logged onto a chain-of-custody form, and placed in a chilled ice chest on crushed ice. Upon completion of well sampling, each well was closed and locked. Well purge water was stored onsite in labeled, closed top 55-gallon steel drums. The purge water was sent to the storage area at Boyd Service Center until it is properly disposed by the City of Tracy. 5.0 Chemical Analysis Five (5) soil samples and three (3)groundwater samples were analyzed at Kiff Analytical LLC, a State-certified analytical laboratory in Davis, California. All samples were tested for the following; Total Petroleum hydrocarbons as Gasoline (TPHG) and Diesel (TPHD), Benzene (B), Toluene (T), Ethylbenzene (E), Xylene (X), Volatile Organic Compounds (VOC), Methyl-tert- butyl-ether (MTBE), and fuel oxygenates tert-Amyl-Methyl-Ether, Ethyl-tert-Butyl-Ether, Di- Isopropyl Ether and tert-Butyl Alcohol, 1,2-Dichloroethane (1-2DCA), and Ethanol and Methanol using EPA Methods 3510/8015, 8020 and 8260/8260B. The analyses were performed and a"normal"ten-day turnaround. 4.0 Brief Conceptual Site Model and Subsurface Conditions The project site is located on the south side of the City of Tracy, located near the northwestern edge of the San Joaquin Valley (see Figure 1). Holocene alluvial fan and fluvial deposits eroded and dissected by streams draining from the nearby Coast Range Hills to the northwest underlie the area. Surficial soils in the region are mapped by the U. S. Department of Agriculture as Capay-Stomar-Zacharias, moderately well drained and moderately fine textured with gravel forming on alluvial fans, interfan basins and stream terraces. Capey soils are mapped as moderately slow penneability. Historic urban development and railroad use has greatly altered or removed the very shallow native soils in the project site vicinity. The underlying alluvial sediment may generally consist of weakly consolidated and irregularly interbedded sand, silt and clay deposits. These subsurface strata may show variable lateral and vertical continuity and extent(Page, 1986; Bertoldi, et al., 1991). Shallow groundwater occurs in the upper 10 to 20 feet below the surface in Tracy. Very large groundwater aquifers underlie the Tracy region at depth and these aquifers produce very large quantities of agricultural and municipal drinking water. Regional groundwater flow in the large aquifer is estimated as northerly (see Well Search above). The largest nearby surface water body, Paine Slough occurs about three miles northeast of the site. Page 4 of 11