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h'q KLEINFELDER <br /> Monitoring wells are generally developed 24 to 48 hours after installation to allow the grout to <br /> set. Each well is first sampled with a clear disposable bailer to visually inspect for a hydrocarbon <br /> layer or sheen. If no product layer or sheen is observed on the water, the well is developed by <br /> surging, pumping or bailing. Surging along the screened interval of the well is performed to <br /> draw the sediment from the formation into the filter pack and the well, and to set the sand pack. <br /> Development continues until the discharge runs relatively clear of fines. Approximately 5 to 10 <br /> well volumes are generally removed from each monitoring well. Discharge water is stored in 55- <br /> gallon drums and left on site for later discharge or disposal by the client, depending on laboratory <br /> results. The drums are labeled with the date, well number, and a contact person and phone <br /> number. <br /> A-3.3 Equipment Decontamination <br /> To reduce the potential for cross-contamination between wells, developing equipment is washed <br /> in a trisodium phosphate or non-phosphate detergent solution and rinsed in distilled water or <br /> steam cleaned prior to use in the next monitoring well. <br /> A-3.4 Well Survey <br /> The locations of soil borings and monitoring wells, and the elevation of the top of the PVC <br /> casings are usually surveyed and tied into permanent markers, if readily available. Survey <br /> accuracy is 0.1 foot for the "x" and "y" coordinates and .O1 foot for the 'Y' coordinate. The depth <br /> to static groundwater is measured from a set location at the top of the PVC casing (usually the <br /> north rim). The depth of water is then subtracted from the elevation of the top of the well casing <br /> to provide a groundwater elevation for each monitoring well location. <br /> 12255.CW1 /STO2R980 Page A-5 <br /> Copyright 2002,Kleinfelder,Inc. December 18,2002 <br />