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ft/ft for the Lower Horizon. <br /> Anomalies in groundwater elevations in Well LM-38, Well LM- <br /> 40, and Well LM-43 were attributed to their proximity to the <br /> Interim Remedial Measure (IRM) system, where possible <br /> testing may have influenced the rapid groundwater <br /> fluctuations in these wells. This is a feasible <br /> explanation, however, the testing schedule of the IRM-wells <br /> was not offered anywhere in the report to substantiate this <br /> theory. Another possible explanation could be the field <br /> methods. The approximately 7 foot drop in water level in <br /> well LM-38 noted in August, 1991 could have been the result <br /> of drawdown from purging, if water elevation in LM-38 was <br /> measured prior to purging in May 1991, post-purging in <br /> August 1991, and prior to purging in September. However, <br /> based on the field logs provided, it was difficult to <br /> determine whether this could have been the case. <br /> 5. Vertical hydraulic gradients between the Upper and Middle <br /> horizons were generally calculated to be downward and <br /> greater than those calculated in May 1991. This would be <br /> consistent with the increased pumping of agricultural wells <br /> due to the drought and possibly the testing of the IRM <br /> system. <br /> • It would be helpful for comparison purposes if the May <br /> 1991 vertical gradient data were included in Table 2-3 . <br /> 6. The vertical gradients between the Middle and Lower horizons <br /> had decreased slightly since May 1991. <br /> • DDRW-Tracy should provide an explanation or propose <br /> possible explanations. <br /> ANALYTICAL RESULTS OF THE AUGUST 1991 QUARTERLY SAMPLING ROUND <br /> 7 . The title for section 2 . 5 reads "ANALYTICAL RESULTS OF THE <br /> MAY 1991 SAMPLING ROUND. " This should be corrected to read <br /> "AUGUST 1991. " <br /> 8 . LM-11, LM-12 , and LM-13 , are the approximately upgradient <br /> wells that were sampled during this round. LM-9 and LM-10, <br /> on the southeastern boundary of the site, were both reported <br /> to be dry. <br /> • DDRW-Tracy should attempt to characterize the quality <br /> of groundwater as it enters the site by sampling <br /> upgradient wells. <br /> • DDRW-Tracy should install more monitoring wells at the <br /> upgradient property boundary. <br /> 2 of 7 <br />