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I December 2, 1998 Page 3 extensive lenses of medium to coarse-grained sand and gravel Quaternary lacustrine deposits also occur in the central and western portions of the valley, and consist of clay, ' silt and sand _ In the site vicinity, surficial deposits are characterized as distal alluvial fan and flood ' plain deposits These deposits generally are less than 10 feet thick and consist of silts, fine sands and less extensive coarse sands and gravels Underlying deposits are referred to as older alluvium and reach a thickness of up to 400 feet These deposits consist of interbedded clay, salt, sand, and gravel Geomorphology and regional drainage patterns suggest a northerly direction of groundwater flow The nearest surface water course to ' the site is the Tom Pain Slough, located approximately 2 miles to the north and ' northeast t ' SCOPE OF WORK To further assess the vertical and horizontal extent of hydrocarbons in soil and groundwater upgradient and downgradient of the project site, the following scope of ' work was performed ' • Permits. PEG obtained the appropriate soil boring and groundwater monitoring ' well permits from San Joaquin County Public Health Services, Environmental Health Division and the City of Tracy • Soil Boring and Well Installation. On October 7, 1998, PEG drilled and installed two groundwater monitoring wells (U-5 and U-6) and one soil boring (B-4) at the approximate locations shown on Figure 2 Field procedures are presented in ' Attachment A Boring logs are presented as Attachment B. • Well Elevation Survey, Well Development, and Well Sampling. The new wells were surveyed for elevation relative to mean sea level by a California State-certified surveyor The surveyor's map is presented as Attachment C The wells were ' developed and sampled by PEG on October 22, 1998 PEG's well development and sampling procedures and field data sheets are presented in Attachment A • Soil and Groundwater Analysis. Soil samples were collected at five foot intervals ' from borings U-5 and U-6 Soil samples were collected at 10, 20, and 23 feet bgs in boring B-4 One groundwater"grab" sample was collected from boring B-4 Soil and groundwater samples were submitted to a California State-certified laboratory ' and analyzed for TPH-g, BTEX, volatile organic compounds (VOCs), and MtBE Certified analytical reports and chain-of-custody documentation are presented as Attachment D • Offsite Sensitive Receptor Survey PEG conducted a search of well records at the California Department of Water Resources, Sacramento Branch Well data is presented as Table 1 Well locations are presented as Figure 1 910017 ]A15OLGWRPT doe _ 1 ,