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• 03 April 2002 AGE-NC Project No. 97-0333 Page 4 of 12 on-site in a 6,500-gallon poly tank(Baker tank).From data collected during the ground water pump test,a transmissivity value was calculated at 955 82/day,a storativity value calculated at 0.032, a hydraulic conductivity value of 0.013 cm/s and a radius of influence projected at ' 140 feet. Results of the March 2001 investigation were reported in Ground Water Aquifer Pumping Test Report-Second Quarter 2001, dated 15 May 2001,prepared by AGE. Between July 2000 and December 2001,five ground water monitoring events were performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground water and to characterize ' ground water flow direction and gradient on the site. Generally, TPH-g was detected in water samples collected from wells MW-1, MW-2, MW-3, MW-4 and MW-6 at concentrations as high as 160,000 µg/l, BTEX constituents as high as 32,000 µg/1 and MTBE concentrations as high as 2,000,000 µg/1; significant concentrations of TAME were detected from MW-1 on isolated occurrences at concentrations as high as 1,100 µg/1. Analytical results of ground water sampling events performed at the site are summarized in Tables 3. Based on ground water data depicted in cross sectional views C-C'(Figure 3)and D-D'(Figure 4), the lateral and vertical extent of petroleum-impacted ground water extends to at least 150 feet bsg ' beneath the site and is not fully defined in any direction.The purpose for the drilling and installation of the proposed multi-level wells are to characterize and delineate the full extent of hydrocarbon- impact soil and ground water on- and off-site. I 2.4. 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 ofAgriculture Soil Conservation Service in 1992,the site arca is within the Delhi- Veritas-Tinnin(DVT)association.The DVT soils are located within dunes,alluvial fans and stream terraces along the Stanislaus River, and generally consist of well drained coarse textured soils. The soils are generally derived from both marine and non-marine sediment, and are generally formed in alluvium derived from granitic and mixed rock sources. Advanced GeoEnviron rental,Inc.