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Report:Groundwater-quality Monitoring—July 29, 2002.- 7500 West Eleventh Street, Tracy, CA. Page 7 <br /> t==ra <br /> The depression in the elevation of the water table due to the presence of floating product <br /> is given by: <br /> W= T (pp/pw) (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 July29, 2002: <br /> W= 0.18 (0.8311.0) = 0.15 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 8.51 ft. <br /> rather than the depth of 8.66 ft. actually measured. This yields a corrected groundwater <br /> table elevation of 39.71 ft. MSL (which is shown on Figure 2) compared to the <br /> =' uncorrected value of 39.56 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 /> k: 3A and MW-313 and in MW-12 and MW-12A are sufficiently great to indicate that the <br /> groundwater monitored by the shallow well at the Iocations of each of those well clusters <br /> has different pieziometric pressures than that in the deeper wells in the same cluster and <br /> therefore must be assumed, at least locally, to monitor aquifers different from that <br /> monitored by the shallow wells. <br /> On July 29, 2002, the mean groundwater gradient in the shallow, near-surface aquifer <br /> beneath the site was approximately 0.004 ft/ft. Although there were some changes in the <br /> details of the groundwater elevation contours, the direction of groundwater flow <br /> t remained substantially unchanged from the north-northeasterly direction that has <br /> prevailed since depths to groundwater were first measured in May 2000. <br /> 2.2 Purging of Monitoring Wells <br /> After the depths to groundwater were measured, a small-diameter, submersible pump was <br /> h used to purge each groundwater-quality monitoring well of stagnant water. The pumped <br /> water was discharged into 5-gal. pails, each of which was, in turn, discharged into an <br /> sic <br />