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0 be used to agitate and condense the sand pack across the slotted casing interval The wells will then be purged with a truck mounted vacuum lift pump until solids have been removed from the well casing and the ground water entering through the sand pack is no longer turbid On the same day as the well is developed, the elevations of the tops of the well casings will be surveyed by a licensed surveyor to the nearest 0 01 foot and tied to an existing benchmark The surveyor will also provide rectangular coordinates for the monitor well QUARTERLY MONITORING OF WELL Depth to water measurements and groundwater samples will be collected from MW6, MW7 and R1 on a quarterly basis The groundwater samples will be analyzed for concentrations of TPH-G, BTEX, and MTBE using EPA method 8260B The results of these analyses will be included within a Quarterly Groundwater Monitoring Report for the site TASK II: PUMP TEST UTILIZING EXISTING MONITOR !TELLS The borehole logs for the existing five monitor wells and additional boreholes drilled at the site show fine silty sand of varying thickness between 15 and 30 feet bgs This aquifer is overlain by 15-20 feet of clay and underlain by an aquitard of clay extending to at least 40 feet bgs The aquifer pump test will be performed in newly installed R1 During the test a submergible pump will be placed in RI and pressure transducers will be placed in Rl, MWI, MW2, and MW3 Groundwater will then be pumped from R1 to a Baker tank at a rate of 2 gallons/minute The Baker tank will be located a sufficient distance from the pumping and recording wells to prevent the weight of the pumped water from interfering with the test results The test will be conducted over a period of three days Automatic data loggers attached to the transducers will record the groundwater elevation changes in the individual wells over the three-day period This data will be plotted and used to determine whether the aquifer is confined, semi-confined, or unconfined The appropriate calculations will then be applied to determine the storativity and transmissivity of the aquifer and the velocity of the groundwater TASK III: AIR SPARGING/ VAPOR EXTRACTION PILOT TEST INSTALLATION OF AIR SPARGING/VAPOR EXTRACTION TRENCH AND PIPING Aar spargang and vapor extraction will be conducted through horizontal PVC piping that will be installed within a trench that traverses the soil contamination plume Figure 4A shows the proposed location of the trench Figure 4B is a cross sectional view of the soil plume The dimensions of the trench will be 40 feet long by 2 feet wide by 20 feet deep 8