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recurring flow patterns in the deep zone are much less apparent than in the shallow zone as groundwater flow is frequently controlled by pumping of on-site production wells and agricultural water supply wells in close proximity to the facility. Radial flow patterns centered about Well B, P4, and P5, with flow occuring in all directions, are common. Also, gradients (possibly induced by pumping of agricultural wells P6 and P7)have contributed to a component of flow in the southwest direction. North and northeast gradients have been observed more frequently in the last three to four ` years and have typically been on the order of 0.002 to 0.003 ft/ft under the footprint of the facility; gradients encountered to the southwest of the facility are frequently an order of magnitude smaller. 2.3 Aquifer Properties Two deep zone aquifer tests were conducted in 1985 prior to the construction of any monitoring wells in the shallow zone (LSCE, 1985). Production well P4 served as the pumped well for the first test, and results yielded an average transmissivity of 275,000 gpd/ft and a storativity of 1.4 x 10-3. P4 has six discrete screened intervals extending from a depth of 144 to 328 feet with a cumulative screen length of 60 feet. It is completed much deeper than any of the dedicated monitoring wells. Production well P5 served as the pumped well for the second test, and results yielded an average transmissivity of 149,000 gpd/ft. P5 was constructed with six discrete screened intervals extending from a depth of 212 to 373 feet with a cumulative screen length of 55 feet. Similar to P4, P5 was completed much deeper than any of the dedicated monitoring wells at the time of the aquifer test. A video log of P5 conducted in November 1989 (LSCE, 1990a)revealed severe encrustation of the well casing. Less encrustation was observed at the screen section extending from a depth of 212 to 222 feet. In April 1990, the lower portion of P5 was abandoned, and the total depth of the well was reduced to 277 feet(leaving only the uppermost three screened intervals). A second aquifer test was conducted in P5, and test results yielded transmissivity values ranging from 66,800 to 102,000 gpd/ft, a storativity of 1.9 x 10-4, and a leakance of 0.08 suggesting a semi- confined(or leaky confined) nature of the deep zone (LSCE, 1990b). Aquifer tests have not been conducted in the shallow zone, however, water level responses in shallow zone monitoring wells MWl and MW3A clearly documented the existence of a hydraulic connection between the shallow and deep zones. The shallow zone transmissivity was estimated to be about 2,200 gpd/ft via specific capacity data from MW3A collected during purging operations (LSCE, 1992). Transmissivity values estimated from specific capacity data derived from short term pumping events often are low, therefore, it is expected that the shallow zone transmissivity values are likely higher than 2,200 gpd/ft. © LUHDORFF & SCALMANINI CONSULTING ENGINEERS 3