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5.3 Ground Water Gradient <br /> t A ground water gradient map was produced from the data obtained from the March 24, <br /> 2004 sampling event (Figure 2). The elevations used in the calculation are summarized <br /> in Table 3. The ground water flow direction was toward the northwest during this <br /> ' sampling event. This gradient and flow direction is consistent with previous monitoring <br /> events. <br /> ' TABLE 3 <br /> Monitoring Well Water Elevations —March 24, 2004 <br /> ' Well Well Collar Depth to Water Ground Water <br /> Number Elevation (feet) Elevation(feet) <br /> feet <br /> 1 <br /> 1ryA 13:5 * <br /> MW-5 57.86' 13.69' 44.17' <br /> MW-6 57.27' 13.20' 44.07' <br /> ' <br /> MW-7 56.15' 11.72' 44.43' - <br /> MW <br /> NOTE: Shaded cells indicate wells not used in gradient calculation. <br /> 6.0 SOUTH WELL ABANDONMENT <br /> Following the installation of the new water supply well, the South Well was taken out of <br /> ' service. The pump was removed from the well and the well was allowed to stabilize <br /> approximately one week prior to performing a video log of the well casing. <br /> ' A downhole video inspection was performed on March 29, 2004 by Hennings Brothers <br /> Drilling. The video log indicated the presence of a steel inner casing liner with an <br /> ' approximate diameter of approximately 8 inches that extended from the surface to <br /> approximately 58 feet in depth. The outer steel casing had a diameter of approximately <br /> 10 inches. The well casing was in poor condition with extensive areas of corrosion and <br /> ' encrustation noted. Hole punched perforations were tentatively identified near the bottom <br /> of the well which was identified at a depth of 126 feet. <br /> ' Based on the condition of the well, the inability to log behind the steel liner-in the upper <br /> 58 feet for a shallow well seal, and the concerns of the Regional Board regarding the <br /> well's potential for serving as a conduit for ground water contamination, a determination <br /> ' was made to abandon the well. <br /> The South Well was abandoned on May 27, 2004 by Hennings Brothers Drilling. An <br /> ' explosive charge was set in the well prior to installing a cement slurry via tremmie pipe. <br /> . The charge consisted of 300 grain detonation cord that extended the full length of the <br /> well. A series of "bombs" were built along the length of the charge and fitted with <br /> American Geological Service, Inc. <br /> CA95DE-029 10 <br />