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. PRIVIANED & CONFIDENTIAL <br /> f. Collected one groundwater sample from each monitoring well along with a blind <br /> duplicate, and submitted the samples for analyses of TPH, BTEX and fuel oxygenates <br /> in accordance with EPA Method 8015M (TPH), and EPA Method 8260 for BTEX and <br /> fuel oxygenates; and <br /> g. Conducted the following quality control procedures: <br /> • One trip-blank was supplied by and returned to the laboratory; <br /> • One duplicate grab-groundwater sample was collected and submitted for analyses <br /> using EPA Methods 8015M and 8260; and <br />' h. Backfilled and repaved the drilled area with a concrete finish. <br /> GEOLOGY AND HYDROGEOLOGY <br /> Stockton is located in the western portion of the Great Valley geomorphic province of <br />' California. The valley is a nearly flat lying, elongate trough trending northwest and <br /> southeast for approximately 450 males. The valley is bordered by the igneous Sierra <br /> Nevada to the east and the sedimentary and metamorphic Coast Ranges to the west. The <br /> surficial and upper several hundred feet of subsurface sedimentary layers consist of a great <br /> thickness of predominantly unconsolidated alluvial and flooplain deposits (dominantly <br /> sand, silt and clay), Quaternary in age, which were derived from the predominantly granitic <br />' mountains of the Sierra Nevada. Beneath the upper sedimentary deposits lies a thick <br /> sequence of marine deposits of Mesozoic age. These units are further underlain by a pre- <br /> Jurassic complex of igneous and metamorphic basement rock.' <br /> In the vicinity of the subject property, depth to groundwater is approximately 60 feet bgs <br /> with a flow direction to the northeast. <br /> SOIL AND GROUNDWATER INVESTIGATION <br /> Soil Boring Permit <br /> Building Analytics applied to the SJCEHD for a soil boring permit prior to advancing the <br /> boring. The well permit was approved on August 5, 1997. <br /> Utility Clearance <br /> 1 Prior to drilling, Building Analytics personnel visited the site and marked the boring <br /> location. Local utility companies were contacted to clear underground utilities at the boring <br /> location. <br /> Drilling and Soil Sampling <br /> On August 26, 1998 Building Analytics conducted the subsurface drilling and soil <br /> sampling at the subject property. The boring was advanced using a Mobile B-61 drill-rig <br /> equipped with hollow-stem augers supplied by Gregg Drilling and Testing of Martinez, <br /> California. <br /> 1 Advanced GeoEnvironmental, Inc., March 1996, Corrective Action Plan. <br /> 4 196075•WFB.Stockton Ph.11 and Quart.Groundwater <br /> r <br />