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Geological Teclutics Inc Page 2 Groundwater Monitoring Report Project No 662 2 November 15,2004 ' on October 26 - 27, 2004 with the installation of one extraction well and two monitoring wells The performance of a dual phase extraction/aquifer pumping test is scheduled for ' December 6— 10, 2004 1.0 GROUNDWATER MONITORING ' 1.1 H dro eolo of Site Y g gY ' The dominant soil type in the upper 40 feet of the subsurface geologic soils investigated is sand, fine to course grained, interbedded with thinner units of plastic clay The average groundwater elevation on August 18, 2004 was approximately 9 06 feet above MSL, which is ' about 31 feet below ground surface This represents a decrease of 2 37 feet since the June 2004 monitoring event, and a cumulative decrease of 4 54 feet since the February 2004 ' monitoring event A groundwater gradient was calculated for the event and the groundwater was found to flow ' N89°E at 0 001 ft/ft Groundwater elevation and gradient data are summarized in Table 1, Appendix A Gradient direction is shown on Figure 2 Gradient Map, and Figure 3 Groundwater Gradient Rose Diagram 1.2 Groundwater Sampling Procedure ' On August 18, 2004, Don Light of Del-Tech mobilized to the site to conduct groundwater monitoring of the four monitoring wells on site ' Before sampling was performed the wells were sounded for depth to water The wells were purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball assembly and i/2 inch tubing Purging continued until the temperature, conductivity, and pH ' of the groundwater stabilized (<10% variation between three readings) indicating that formation water representative of aquifer conditions was entering the wells These water quality parameters were measured at intervals of each well volume purged ' Once purging was complete, a water sample was collected from the Waterra tube Care was taken to minimize sample agitation Once the sample container was filled and capped, the ' bottle was inverted, tapped, and checked for headspace bubbles The sample container was identified and labeled with a unique designation, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory A P sampling All non-disposable equipment was decontaminated using a hot water washer and P g g ui P detergent before and between uses Disposable gloves were used by the technician to collect ' all samples and were changed with each sample collection