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3.2 Well Installation, Development and Surveying Morutoring well MW-4 was installed in borings MW-4. The wells were constructed of four- inch diameter polyvinylchloride (pvc) pipe Well construction procedures followed, and ' materials used were in accordance with the approved workplan. Well construction diagram for monitoring well MW-4 is included in Appendix A. Monitoring well MW-4 was ' completed to a depth of 44.5 feet bgs ' Momtoring well MW4 was developed subsequent to installation, yet prior to setting the bentonite and cement-grout seal. The well was developed using the drill ng to mechanically ' surge and bail the well Approximately 20 gallons of ground water was removed from the well during the development process After well development was completed for the well, ' the level of the sand-filter pack surrounding each well was gauged to determine if any settling had occurred during development. Additional sand was added to the borehole ' annulus as needed to bang the sand pack up to 1.5-feet above the top of the well screen. The sanitary seal and traffic-rated well box were then set. The top of casing elevation of monitoring well MW-4 was surveyed by ESE on May 28, ' 1993. The well was surveyed to an accuracy of 0.01-foot using a Leitz automatic level. The datum for this survey was concrete surface of the site storage tank which was established to ' be 37 feet above mean sea level (U.S.G.S, 1959). The Leitz automatic level was also used to survey the horizontal locations of the monitoring well with respect to property boundaries. ' The surveyed elevations of the top of casings for monitoring wells MW-1 through MW-4 are included on Table 1 - Ground Water Elevations. ' 33 Ground Water Monitoring and Sampling On May 28, 1993 ESE measured the depth to ground water in monitoring wells MW-1 ' through MW-4, using an electric tape. Depth to water measurements are presented on Table 1. F\ \5925009\ADnSAssE.RYr 1