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I r30 April 2005 AGE-NC Project No 95-0141 ' Page 3 of 10 2 14 Monitoring Well Development On 23 December 2004, monitoring well MW-13 was developed by Cascade Drilling of Rancho ' Cordova Groundwater was purged from each monitoring well using a steel bailer until groundwater was visually sediment free, approximately 55 gallons of water were removed from well Purged ground water was containerized in properly labeled DOT-approved model 17H 55-gallon drum and ' was stored on-site 2 15 Well Head Survey On 10 March 2005, California state-licensed surveying engineer from Morrow Surveying surveyed the location and elevation of monitoring wells MW-3 through MW-13 and EX-1, the global positioning system(GPS)location was surveyed to the nearest 0 1-foot relative to coordinate datum NAD 83 (1986),and the elevation at the top of the well casing was surveyed to the nearest 0 01-foot ' relative to NAVD 83(1986) from GPS observations The results of the monitoring well survey are recorded in Table 1 The surveying report (Morrow Surveying) is presented in Appendix C 2 16 Equipment Decontamination EAll augers were cleaned prior to advancement in each boring location The sampling equipment was washed in an Alconox solution and triple rinsed with water prior to each sampling run to avoid cross-contamination 2 2 QUARTERLY WELL MONITORING On 23 and 29 December 2004, the fourth quarter ground water monitoring event was conducted at the site A total of fifteen wells were monitored and sampled 2 2 1 Well Monitoring and Evacuation A Solinst water level meter was used to measure the depth to ground water in wells MW-3, MW-5, MW-6, MW-7, MW-8A/B through MW-12A/B, MW-13 and EX-1 relative to the tops of the well casings(Table 1) After the depth-to-ground-water measurements,a minimum of three casing-water volumes of water were purged from each well using Watera Hydro-Lift II pump for wells MW-3, MW-5, MW-7 and MW-8A through MW-12B and a submersible pump was used for well MW-13 Approximately 3 75 to 13 gallons of water were removed from shallow-screened wells MW-3, Advanced CcoEnvironmental,Inc