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... .. . .. . .. . <br /> previously, the highest level was 12.23 feet from the surface on January 10, 1995. <br /> ?- } The average depth-to-water in the wells has risen 3.00 feet since October 29, 1996, <br /> when it was 15.14 feet. Table 2 lists clock times of soundings for monitoring activities <br /> performed since September 19, 1994, with Stockton-corrected times and heights of <br /> highest & lowest tides. Horizon Field Methods and Procedures are included as <br /> . '� Appendix A. Monitoring Well Data Logs are included as Appendix B. <br /> The local groundwater flow direction on January 22, 1997 was approximately N81°E <br /> along an overall gradient of 0.018 (see Figure 3). Between October 29, 1996 (when <br /> the flow direction was due east) and January 22, 1997, the flow direction has shifted 90 <br /> to the north. <br /> Analytical Results <br /> The sample collected from monitoring well MW-6 revealed 2458 µg11 of TPH-g and 374 <br /> _i µg11 of benzene. TPH-g and benzene have increased since the monitoring activity of <br /> October 29, 1996. Only benzene exceeds the MCL of 1µg11 assigned by the California <br /> l-j Department of Health Services. <br /> .-, The analytical results are compiled in Table 3. The Sherwood Labs analytical report <br /> and chain-of-custody are included as Appendix C. <br /> r SUMMARY <br /> On January 22, 1997, groundwater was sounded at an average depth of 12.14 feet <br /> below the tops of the well casings (see Table 2). The average depth-to-water in the <br /> wells has risen 3.00 feet in the 3-month period since October 29, 1996 when the <br /> _i average depth-to-water was 15.14 feet. The average depth-to-water exceeded its <br /> f=_ previous highest level by 0.09-foot since the soundings of January 10, 1995 when the <br /> average depth was 12.23 feet from ground surface. <br /> The local groundwater flow direction on January 22 was N81°E along a gradient of <br /> 0.018. Between October 29, 1996 (when the flow direction was due east) and January <br /> 22, 1997, the flow direction has just shifted 90 to the north but has remained easterly. <br /> In the sample collected from MW-6 for analysis at Sherwood Labs, TPH-g increased <br /> from 1210 to 2458 µg/l between October 29, 1996 and January 22, 1997. Benzene <br /> concentrations increased from 87 to 374 µg11 in the same period. Sampling was not <br /> required for monitoring wells MW-4, MW-5, MW-7, and MW-8 because the wells have <br /> never exhibited a history of yielding gasoline-impacted samples. <br /> DAYNE L. FRARY, GEOLOGIST 5 <br /> 1296-012.197 <br /> :i <br /> l <br />