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' 14 October 2004 AGE-NC Project No 03-1055 ' Page 3 of 6 ' approved model 17H 55-gallon drums and was stored on-site Field sheets and data are included in Appendix C ' 2 1 5 Well Head Survey On 16 August 2004,a California state-licensed surveying engineer from Morrow Surveying surveyed ' the location and elevation of monitoring wells MW-6 and MW-7, 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 88 from GPS observations The elevations of wells MW-6 and MW-7 were determined to be 49 29 and 48 26 feet above mean sea level(MSL),respectively The results of the monitoring well survey are recorded in Table 1 The surveying report (Morrow Surveying) is presented in ' Appendix D i2 16 Equipment Decontamination i All augers used 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 1 2 2 QUARTERLY WELL MONITORING PROCEDURES iThe initial quarterly ground water monitoring event was performed on 09 August 2004,groundwater monitoring was performed on monitoring wells MW-5 through MW-7 i 2 2 1 Well Monitoring and Evacuation The depth to ground water in each monitoring well was measured from the top of the well casing to the nearest 0 01-foot utilizing a Sollnst water level meter Ground water elevation in each well was i calculated by subtracting the measured depth to ground water from the surveyed casing elevation (Table 1) iAfter water levels were measured, approximately 3 to 3 5 gallons of water(a minimum of 3 casing- water volumes per well) were purged from monitoring wells MW-6 and MW-7 using disposable plastic bailers MW-5 was purged dry prior to removal of 3 casing volumes, therefore the well was allowed to recharge for at least one hour prior to sample collection Ground water temperature,pH, • and conductivity were measured at regular Intervals during purging using an Oakton water analyzer Advanced GcoEnvironmental,Inc