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# 0 information at that time. Clark Well later performed some remedial work on the well and provided Gillies Trucking with a work order that indicates that the total depth of the well is approximately 100 feet. Hence, although water has not been present within the Modesto Formation continuously during the past eight years, the fact that the well has continued to produce water indicates that it is screened within the Riverbank Formation. EHD has requested confirmation of this conclusion in the form of a downhole geophysical survey utilizing a video camera to locate and observe the well screens. The suggested purpose of this survey is to aid in determining the magnitude of the influence that pumping of the domestic well exerts on the groundwater plume at the site. Upgradient Environmental will retain an experienced downhole logging company to perform this survey and provide a videotape copy to EHD. Task 2. Pumping Tests of the Gillies and Barbot Domestic Wells EHD recommended that Gillies "characterize the pumping influence of G-1 and the Barbot wells on the plume by utilizing leveloggers in appropriate site monitoring wells during pumping from each water well." This task is somewhat of a moot point, for at least two reasons: 1) EHD also has instructed Gillies Trucking to destroy the domestic wells (see Task 3), which will eliminate any influence that these wells might have on the plume; and 2) as explained in Item 2 in section 3.0 above, groundwater in the Riverbank Formation is minimally impacted by diesel fuel. The impact is significant only when the water level is within the Modesto Formation, which has not been the case for more than two years. Pumping the domestic wells, which are not screened within the Modesto Formation, will draw only uncontaminated groundwater from the Riverbank Formation, and therefore will provide no information on the migration of contaminants from the main impacted zone in the Modesto Formation. A third possible reason that this test is moot is that the Gillies domestic well is more than 135 feet from the nearest monitoring well that is screened within the Riverbank Formation (GT-1). This may be beyond the influence of the domestic well in the short time intervals during which this well is pumped (because it is used only in the facility's rest rooms, the pump operates intermittently for a total of no more than 2 hours per day). Running a continuous pumping test for a long period would thus yield an erroneous impression of the true effect of the domestic well under normal operating conditions. This problem will be worse in the case of the Barbot well,which is even farther away from any of the Gillies monitoring wells. To minimize the potential for the pumping test to overstate the influence of the domestic wells, the Gillies well (G-1) will be pumped continuously for a period not longer than 2 hours. The proposed pumping rate is 10 gallons per minute (assuming that the pump will yield this rate), but this will be adjusted if necessary to avoid draining the pumping well. A transducer will be placed in GT-1 to record any changes in the depth to groundwater during pumping. The resulting drawdown(if any)in GT-1 will be presented in graphical form.