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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS 5 On August 7, 1998, Ramage Environmental monitored and sampled groundwater at the site 2.1 Groundwater Monitoring Depth-to-groundwater measurements were taken in all seven groundwater monitoring wells and the two deep soil vapor extraction wells (VW-1 and VW-2) to evaluate groundwater flow and gradient characteristics The depth-to-groundwater beneath the site ranged from 37 44 feet below ground surface (bgs) in MW-1 to 41 30 feet bgs in MW-7 The groundwater elevation beneath the site ranged from a high of 23 01 feet below mean sea level (MSL) in VW-1 and MW-6 to a high of 23 13 feet below MSL in MW-5 Groundwater levels have risen an average of 0 77 feet since groundwater levels were last measured on May 1, 1998 In the past year, groundwater levels have risen an average of 8 52 feet Since May 1992, the groundwater levels have risen an average of 28 78 feet The historical groundwater monitoring data are summarized in Table 1 The groundwater flow direction and gradient are illustrated on the groundwater surface map (Figure 3) In general, the groundwater gradient was calculated at 0 001 foottfoot in a northerly direction This result is consistent with historical groundwater flow and gradient data 2.2 Groundwater Sampling and Analysis Groundwater from MW-6, MW-7 and the two deep soil vapor extraction wells (VW-1 and VW-2) was sampled to evaluate the concentration of gasoline hydrocarbons at the groundwater table The groundwater monitoring wells (MW-1, MW-2, MW-3, MW-4 and MW-5) were not sampled because of groundwater levels significantly above the screened interval of these wells f - Each o the four wells (MW 6, MW-7, VW-1 and VW-2) was purged of at least three well volumes using a decontaminated battery-operated pump Following purging, groundwater samples were collected from the four wells using dedicated and disposable sampling bailers The groundwater samples were contained in laboratory-supplied glassware, labeled, sealed in a Nplastic bag and packed in an iced cooler for transport under chain-of-custody documentation to Sparger Technology, Inc (Sparger) a state of California certified analytical laboratory(#1614) The laboratory analyzed the groundwater samples for Total Petroleum Hydrocarbons (TPH)-as- 2 r�