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s-. Report: Groundwater-quality Monitoring—October 27, 2003: 7500 West Eleventh Street, Tracy, CA. Page 7 <br /> Assume relative proportions of diesel and gasoline in the floating product in Monitoring <br /> Well MW-7 are in the same ratio as the concentrations of diesel and gasoline in the <br /> sample of groundwater recovered from that well on December 13, 2001. They were, <br /> �. respectively, 800,000 µg/L and 61,000 pg/L. (See Table 2.) <br /> Thus, the estimated specific gravity of the floating product in well MW-7 is: <br /> pp = 0.83 <br /> The depression in the elevation of the coater table due to the presence of floating product <br /> is given by: <br /> �. W= T (pp/p,,) (Equation 1) <br /> Where: <br /> W= the depression of the water table <br /> T = the thickness of floating product in the monitoring well <br /> pw = the specific gravity of the groundwater <br /> pp = the specific gravity of the floating product <br /> Thus, in the case of the floating product measured in well MW-7 on October 27, 2003: <br /> W= 0.55 (0.8311.0) = 0.46 ft. <br /> Accordingly, when drawing the contours shown on Figure 2, the elevation of the <br /> groundwater in well MW-7 was based on an assumed depth to groundwater of 9.92 ft. <br /> rather than the depth of 10.38 ft. actually measured. This yields a corrected groundwater <br /> table elevation of 38.30 ft. MSL (which is shown on Figure 2) compared to the <br /> a" uncorrected value of 37.84 ft MSL given in Table 1. <br /> In addition, the groundwater elevations in Wells MW-3A, MW-313 and MW-12A were <br /> not considered when the groundwater contours were drawn because, although small in <br /> magnitude, differences between the elevations of the groundwater in Wells MW-3, MW- <br /> 3A and MW-3B and in MW-12 and MW-12A are sufficiently great to indicate that the <br /> groundwater monitored by the shallow well at the locations of each of those well clusters <br /> has a different pieziometric pressure from that of the deeper wells in the same cluster. It <br /> must therefore be assumed, at least locally, that the shallow wells monitor aquifers <br /> different from those monitored by the deeper wells. During the October 27, 2003 <br /> sampling round, the groundwater level in Monitoring Well MW-313, which is screened in <br /> an aquifer the top of which is some 37 ft. BGS, was 0.39 ft. higher than that in <br /> Monitoring Well MW-3, which is screened in the shallow, near-surface aquifer, while the <br /> level in Monitoring Well MW-3A was 0.09 ft. lower than that in Monitoring Well MW-3. <br /> sic <br />