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ASSOCIATEC\V S INC MW-3 contained detectable levels of petroleum hydrocarbons A program of quarterly groundwater monitoring and sampling was initiated in March 1994 In August 1995, Smith Technologyconducted a subsurface site investigation to further define the g extent of impacted groundwater at the site Smith Technology supervised the installation of monitoring 1 wells MW-4, MW-5 and MW-6 These three new wells were incorporated into the groundwater monitoring program Analytical results of groundwater samples from the six monitoring wells indicated the presence of elevated concentrations of petroleum hydrocarbons in the vicinity of MW-3 and MW- 6, at the northeastern corner of the site ' In November 1998, ATC conducted a subsurface site investigation to evaluate the vertical and horizontal extent of hydrocarbon impacted soil ATC supervised the installation of three soil borings S131, S132, and S133 from approximately 30 to 50 feet bgs Analytical results of soil ' samples indicated the vertical extent of soil contamination had been defined, but the horizontal extent of impacted soil was not fully defined on the northeastern corner of the site Site activities are summarized in ATC's Summary Report of Additional Subsurface Investigation, dated January ' 27, 1999 2.0 SUBSURFACE CONDITIONS 2.1 Hydrogeolosy ' Water level measurements were collected from wells MW1 through MW6 on August 20, 2002 Water levels ranged from 27 75 to 28 56 feet below the tops of the well casing elevations Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer ' beneath the site flowed towards the northeast The average hydraulic gradient on August 20, 2002 was calculated to be 0 00076 ft/ft or approximately 4 ft/mile A summary of groundwater monitoring data is presented in Table 1, and groundwater elevations and contours are illustrated on Figure 3 ' 3.0 GROUNDWATER PUMPING PILOT TEST The objective of the pump test was to evaluate whether groundwater extraction has the potential ' to lower the concentrations of dissolved petroleum hydrocarbon constituents to acceptable levels over a reasonable period The following information was collected and evaluated ' • Radius of influence of groundwater extraction, • Groundwater drawdown, • Hydrogeologic properties of the aquifer, ' Mass extraction rate of groundwater S 1Envw..enta1162611IVmoAslpump_test doc 2