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File No 20-3769-O11AO5 k4 KLE IN FELD E R <br /> November 11, 1994 <br /> B-3.2 Monitoring Well Development <br /> The wells are developed to reduce the effects of drilling on the formation and to increase the <br /> effective hydraulic radius of the well <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 acrylic bailer to visually inspect for hydrocarbon <br /> layer or sheen If no product layer of 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 /> The sediment-laden water is purged from the well at a rate of between 0 75 to 10 gallons per <br /> minute (gpm) depending on recharge rate and casing size Development continues until the <br /> discharge nuns relatively clear of fines Approximately 5 to 10 well volumes generally are <br /> removed from each monitoring well Discharge water is stored in 55-gallon drums and left on <br /> site for later discharge or disposal by the client, depending on laboratory results <br /> B-3.3 Equipment Decontamination <br /> To reduce the potential for cross-contamination between wells, developing equipment is washed <br /> in a trnsoduum phosphate or lab grade detergent solution and rinsed in distilled water or steam <br /> cleaned prior to use in the next monitoring well <br /> B-3.4 Well Survey <br /> The locations of soil borings and monitoring wells and the elevation of the top of the PVC <br /> casings will be surveyed and tied into permanent markers, if readily available Survey accuracy <br /> is 0 1 foot for the "x" and "y" coordinates and 0 1 foot for the "z" coordinate The depth to <br /> static groundwater is measured from a set location at the top of the PVC casing The depth of <br /> water is then subtracted from the elevation of the top of the well casing to provide a groundwater <br /> elevation for each monitoring well location <br /> B-4.1 Water Level Measurements <br /> Water level measurements are made in the wells prior to purging and sampling the wells <br /> Measurement protocol is as follows <br /> 1 The wells are opened and allowed to equilibrate with the atmosphere <br /> ETH and WC194 f S 4 o e <br /> Copyright 1994 Kleinfelder, Inc Page <br />