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• 26 October 2000 AGE-NC Project No 97-0333 Page 3 of 7 2000, ground water monitoring and sampling were performed on each newly installed well From the field data, the general ground water gradient at the site was calculated to be approximately 0 001 ft/ft and directed towards the north Low levels of TPH-g, BTEX, MTBE and TAME were detected in soil samples collected from MW-1, MW-2, MW-3 and MW-4 TPH-g was detected in water samples collected from wells MW-1, MW-2, MW-3 and MW-4 at concentrations as high as 140,000µg/1 BTEX compounds were detected in water samples collected in the four wells at concentrations as high as 28,000 µg11, the greatest benzene concentration was detected from MW-2 at a concentration of 13,000 µg/1 MTBE was detected in water samples collected from MW-1, MW-2 and MW-3 at concentrations as high as 980,000,ug/l TAME was detected in the water sample collected from MW-1 at a concentration of 580 µgll Analytical results of soil and ground water samples are summanzed in Tables 2 and 4 23 REGIONAL GEOLOGIC SETTING The property is situated within the Great Valley Geomorphic Province of California, a large, elongate, northwest trending, asymmetric structural trough The Great Valley Province has been filled with thick sequences of sediment ranging in age from Jurassic to Recent, creating a nearly flat- lying alluvial plain, extending from the Tehachapi Mountains in the south to the Klamath Mountains in the north The western and eastern boundaries of this province are comprised of the California Coast Range and the Sierra Nevada, respectively Rocks composing the basement complex of the province have not been completely defined but are believed to be metamorphic and igneous in origin The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys, respectively Based on the General Soil Map from the San Joaquin County Soil Survey, published by the United States Department of Agriculture Soil Conservation Service in 1992,the site area is within the Delhi- Ventas-Tinrnn (DVT) association The DVT soils are located within dunes, alluvial fans and stream terraces along the Staruslaus River, and generally consist of well-drained, coarse textured soils The soils are generally derived from both marine and non-marine sediment, and arc generally formed in alluvium derived from granitic and mixed rock sources 24 GROUND WATER DEPTH AND GRADIENT The estimated depth to ground water at the site is approximately 20 feet below surface grade (bsg) based on inforirnation from Lines of Equal Depth of Water Wells Fall 1998, published by the San Joaquin County Flood Control District and Water Conservation District (SJCFCD) Based on rcvie" of a rLgional ground water elevation map published by the SJCFCD, the prevailing ground water Idculccd(,�uF�:�liancsiuiti, ,