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6 2 Groundwater Monitoring Well Development 40 The wells were developed using a submersible pump Groundwater was pumped to the surface and collected in a DOT approved 55-gallon drum for containment until the effluent became clear The pump was then turned off to permit the groundwater in the monitoring well to recharge and to allow the water standing in the discharge line to surge back into the well The pump was again engaged after a few minutes and the groundwater pumping process again repeated The cycle of pumping and back surging continued until the effluent contained less than ten percent (10%) fine materials 6.3 Groundwater Monitoring Well Purging On August 25, 1993, the County witnessed AGI conduct the purging and sampling of the groundwater monitoring wells MW-1, 2, and 3 Three and one-half to five well casing volumes were removed from each well using a purge pump Groundwater parameters of temperature, pH, and conductivity were measured after the removal of each well volume When the parameter readings were within 10% of the preceding measurements the well was considered stabilized for sampling The purge data sheets showing the field results are included as Appendix C The amount of each well volume was calculated by multiplying the amount of free- standing groundwater in each well by the product of the square of the well casing radius and the constant Pi All groundwater measurements were made referenced to the top and north side of the casing in each well to the nearest one hundredth (0 01) of a foot using a Sol€nst water level indicator The depth to groundwater was measured only after each well was allowed to adjust to atmosphere conditions by stand open for approximately one-half hour. The depth to the bottom of free-standing groundwater in each well was measured with a weighted tape. The Soloist water level indicator and the weighted tape were both washed in Alconox and rinsed with clean water prior to entering each well to prevent cross contamination 6 4 Groundwater Sample Collection Each well was sampled upon completion of purging using a disposable PVC baler A new bailer was lowered into each well to collect a sample of the groundwater for laboratory analyses Two 40 milliliter VOA vials were filled with the collected groundwater sample and sealed with teflon-lined lids, taking care to assure that air bubbles were not present The water samples were labeled, and immediately placed in an iced cooler maintained below 40 centigrade for storage and transport, accompanied by a travel blank The samples were logged on a chain of custody document, and transferred to Halcyon Laboratories of Bakersfield, a California certified laboratory for the specified analyses 12 of 17