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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On November 5, 1998, Ramage Environmental monitored and sampled groundwater at the site. <br /> V <br /> 2.1 Groundwater Monitoring <br /> Depth-to-groundwater measurements were taken in all seven groundwater monitoring wells and <br /> the two deep soil vapor extraction wells (VW-1 and VW-2) to evaluate groundwater flow and <br /> gradient characteristics. The depth-to-groundwater beneath the site ranged from 38.12 feet <br /> below ground surface (bgs) in MW-1 to 42.19 feet bgs in MW-7. MW-7 is completed above- <br /> grade and protected with a monument casing. The groundwater elevation beneath the site <br /> ranged from a high of 23.72 feet below mean sea level (MSL) in VW-1 and MWA to a low of <br /> 23.95 feet below MSL in MW-7. Groundwater levels have dropped an average of 0.79 feet since <br /> groundwater levels were last measured on August 7, 1998. In the past year, groundwater levels <br /> have risen an average of 9.69 feet. Since May 1992, the groundwater levels have risen an <br /> average of 28.04 feet. The historical groundwater monitoring data are summarized in Table 1. <br /> The groundwater flow direction and gradient are illustrated on the groundwater surface map <br /> (Figure 3). The groundwater gradient was calculated at 0.002 foot/foot in a northeasterly <br /> direction. This result is consistent with historical groundwater flow and gradient data. <br /> w.. <br /> 2.2 Groundwater Sampling and Analysis <br /> Groundwater from MW-6, MW-7 and the two deep soil vapor extraction wells (VW-1 and VW-2) <br /> was sampled to evaluate the concentration of gasoline hydrocarbons at the groundwater table. <br /> The groundwater monitoring wells (MW-1, MW-2, MW-3, MW-4 and MW-5) were not sampled <br /> because of groundwater levels significantly above the screened interval of these wells. <br /> Each of the four wells (MW-6, MW-7, VW-1 and VW-2) was purged of at least three well <br /> volumes using a decontaminated bailer. Following purging, groundwater samples were <br /> collected from the four wells using dedicated and disposable sampling bailers. The groundwater <br /> samples were contained in laboratory-supplied glassware, labeled, and packed in an iced cooler <br /> for transport under chain-of-custody documentation to Kiff Analytical, LLC (Kiff) a state of <br /> California certified analytical laboratory (#2236). <br /> 3 <br />