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December 16, 1992 MACAWMA Unocal Service Station No 6981, Stockton, California Working To Restore Nature RESNA estimates that a wellhead flowrate of 80 cubic feet per minute will result in an effective radius of influence of approximately 50 feet per vapor-extraction well The area of influence is shown on Plate 4 i Evaluation of Aquifer Parameters RESNA conducted a series of constant-rate pumping tests in August, 1992 at the site to evaluate hydrologic and well conditions and provide baseline information for the possible design and operation of a ground-water remedial system The testing program comprised three separate elements designed to provide different types of information The first 1 element consisted of a period of static ground-water monitoring These data were used to establish initial conditions and to aid the evaluation of the significance of water-level changes observed during the later pumping test 1 , The second element of the test program consisted of five short-term constant-rate tests using well PTW-1 This series of tests provided information regarding the well productivity and efficiency The tests were also used to select the rate for the longer-term constant-rate pumping test which constituted the third element of the testing program The long-duration, constant-rate pumping test utilized well PTW-1 for production and wells MW-6, MW-7, and MW-11 as observation wells Data from this test were used to evaluate the hydraulic parameters transmissivity (T) and specific yield (S,) and to provide information regarding aquifer boundary conditions and anisotropy The pumping test is described in more detail in Appendix E 1 Based on the results of the pumping test, the water-bearing zone from approximately 55 to 75 feet below grade is heterogeneous, anisotropic, and unconfined The transmissivity of this zone is approximately 0 4 to 0 8 ft2/min and the specific yield is approximately 5 to 10 38032-10 9 r