SITE INFORMATION AND CORRESPONDENCE

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• , 4 Overhead/Lodi Door Company -3- 3 October 1990 The S, T and K values are usually estimated from data collected when performing a pumping test. We discussed the problems with conducting a pumping test on the shallow ground water zone, using the existing monitoring well system at the 0/LDC facility. The wells are only two inches in diameter, the water table is probably less than nine feet above the bottom of the well screens, and there may be multiple shallow water bearing zones (i .e. the wells might not all be screened in the same water bearing zone) . An alternative is to wait for the ground water table to return to higher levels before conducting additional aquifer tests on the shallow ground water zone. We also discussed the problem of defining the ground water gradient. The gradient changes depending on which wells you choose for the calculation. It has been hypothesized that multiple shallow water bearing zones exist beneath the site. It appears that the ground water gradient is in the southeasterly or easterly direction. (Mr. Glick stated that he feels the gradient is in an easterly direction.) If that is true, MW-1 and MW-2 are downgradient from the impoundment. The July 1990 sampling data showed chromium at 0.081 mg/l in MW-2. MW-2 is on the southern boundary of 0/LDC's facility. Therefore, Mr. Vaughn stated that additional wells would be necessary to define the plume. Mr. Poole and Mr. Schweizer stressed that they don't believe the chromium levels in the ground water are significant enough to warrant the cost of further investigation. Additional downgradient wells may need to be placed off site, since existing contaminated wells are at the property boundary. We agreed to look further into the chromium issue and determine what the Board will require in terms of future monitoring and installation of additional monitoring wells. JEM:jm Attachment