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Ceofagica(Tecfiinics Inc. <br /> C&S Equipment Page 2 <br /> Groundwater Monitoring Report—Site Closure Request <br /> ix Project No.336.2 <br /> October 11,2000 <br /> 1.0 GROUNDWATER MONITORING <br /> 1.1 Hydrology of Site <br /> Over the course of the project groundwater levels have remained fairly constant. The top of <br /> casing elevations were surveyed into the nearest USGS benchmark on December 18, 1997, <br /> this caused what appears to be a large change in the groundwater elevations at the site. <br /> On August 31, 2000, depths to water were measured in all eight monitoring wells The <br /> groundwater elevation, gradient and direction were calculated. The average elevation was <br /> 39.42 feet AMSL. The gradient was North 16° West with a slope of 0.004 ft/ft (as <br /> determined from MW-1, 2 & 3). <br /> Table 1 of Appendix A summarizes the groundwater level measurements to date. <br /> Groundwater gradient calculations show that the dominant groundwater flow is in a northerly <br /> direction with the slope ranging from 0.004 ft/ft to 0.0036 ft/ft. Figure 2 is a groundwater <br /> gradient map from this latest sampling event. <br /> 1.2 Groundwater Sampling Procedure <br /> E` On August 31, 2000, GTI personnel arrived on-site, opened the wells, and measured the <br /> depth to water with an electrically actuated sounding tape. The water level reading was <br /> recorded to an accuracy of 0.01 foot. In wells where free floating product was suspected, a <br /> clear disposable bailer is used to gauge the interface. <br /> Stagnant water in the well casing was purged using a centrifugal pump as recorded in the <br /> field logs (Appendix C). The rate of well purging was monitored. The well was purged of at <br /> least three casing volumes and until the groundwater parameters (temperature, conductivity, <br /> and pH) had stabilized (Appendix C) indicating that water, representative of actual aquifer <br /> conditions, was entering the well. Groundwater parameter stabilization was characterized by <br /> F three successive readings within 10%. <br /> All water removed from the monitoring well and not used as a sample, was placed in a 55 <br /> gallon DOT (Department of Transportation 17-H) approved container that is properly labeled <br /> and temporarily stored on-site. <br /> A bailer was used to collect each sample. Extreme care was exercised while collecting <br /> f <br /> k <br /> L <br />