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FIELD PROCEDURES r` FOR GROUNDWATER MONITORING DEVELOPMENT AND SAMPLING Groundwater Monitoring Well Development The groundwater monitoring wells were developed to consolidate and stabilize the filter pack to optimize well production and reduce the turbidity of subsequent groundwater samples. Well development was accomplished by using a disposable bailer to evacuate the water and sediments before establishing the bentonite seal during well construction. Development continued until the groundwater was relatively free of sediment. Well development fluids were placed into properly-labeled Department of Transportation approved drums for disposal. Groundwater Level Measurement Before groundwater sampling activities, the groundwater level in each well was measured from the permanent survey reference point on top of the well casing. Groundwater in each well was monitored for free-floating product or sheen. The depth to groundwater was measured to an accuracy of 0.01 foot from the top of the polyvinyl chloride well casing using an electronic sounder. Groundwater Monitoring Well Sampling The wells were purged of 3 casing volumes and the above parameters stabilized before sample collection. Purging was accomplished using am above ground duel-diaphragm pump equipped with disposal tubing, which was replaced between each well development to prevent cross-contamination. The groundwater samples were collected using a disposable bailer, and carefully transferred into appropriate clean, glass, laboratory-supplied containers. The sampling technician wore nitrile gloves at all times during purging and well sampling. The samples were clearly labeled with well number, site identification, date and time of collection, and sampler's initials, and transported in an iced cooler to a state-certified laboratory following preservation and chain of custody protocol. Hydraulic Conductivity Testing Hydraulic conductivity testing was performed prior to groundwater sampling activities by evacuating groundwater from each well to the greatest extent practicable using a Grundfos 2- inch-diameter submersible electric pump. Before each use, the submersible pump was decontaminated by immersion in and pumping of a water and Liquinox solution followed by a rinse of tap water and deionized water. After well evacuation, the pump was shut off and the water level was measured using an electronic depth to water meter at 15 to 30 second intervals until the water level recovered to within 80 percent of the static water level prior to pumping.