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3.0 PROJECT RESULTS 1 31 Geology and Hydrogeology ' Soils observed during drilling consisted of interbedded sequences of clay, silt and fine sand The uppermost 15 to 20 feet of soil beneath the site consisted of a laterally continuous, fining-upward ' silty fine sand and fine sand sequence Underlying this sandy surface interval, a less permeable sequence of silt and clay soils was observed to the total drilling depth of 30 feet During previous ' investigations, a well-graded sandy gravel sod was observed at a depth of approximately 43 feet The descriptions of soil observed during the drilling are included on the Geoprobe Sample Collection and Description Logs (Appendix C) During drilling on December 5 and 6, 2002, saturated soil was first encountered at between 214 and 22 9 feet bgs On December 19, 2002, the static depth to the groundwater table, as measured in the three monitoring wells, ranged from 20 90 feet bgs in MW-2 to 21 12 feet bgs in MW-3 The corresponding groundwater surface elevations ranged from a high of 15 75 feet ' above mean sea level (msl) at MW-2 to a low of 15 52 feet above msl at MW-3 The resulting groundwater surface appears as a regular plane dipping to the northwest at a gradient of approximately 0 0033 foot/foot A groundwater surface contour map is included as Figure 3 The well construction details and groundwater monitoring data are summarized in Table 3 Between September 26 and December 19, 2002, the groundwater surface rose an average of 3 06 feet, the groundwater gradient increased from 0 0016 to 0 0033 foot/foot, and the ' groundwater flow direction shifted approximately 25 degrees toward the northwest 32 Analytical Results 1 Only two of the 12 soil samples analyzed during the investigation contained detectable concentrations of only TPH-as-diesel The sample collected at 25 feet from G-7 contained 1 2 mg/kg of TPH-as-diesel and the sample collected at 20 feet from G-8 contained 2 4 mg/kg of TPH-as-diesel TPH-as-gasoline, BTEX, the five oxygenate compounds and 1,2-DCA were not ' detected in any of the 12 soil samples These soil sample analytical results are summarized in Table 1, and the laboratory reports are included in Appendix D 12 1 1