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gallons per minute (gpm) depending on recharge rate and casing size Development continues <br /> until the discharge runs relatively clear of fines Approximately 5 to 10 well volumes <br /> allon <br /> drums <br /> generallyare <br /> left onos to for later discharge or disposal by the Dischargech monitoring well lient water depending on laboratory <br /> atory <br /> drum <br /> results <br /> A-3.3 Equipment Decontamination <br /> To reduce the potential for cross-contamination between wells, developing equipment is <br /> washed in a trsodium phosphate solution and rinsed in distilled water or steam cleaned prior to <br /> 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 is usually surveyed and tied into permanent markers, if readily available Survey <br /> accuracy is 0 1 foot for the "x" and "y" coordinates and .01 foot for the "z" coordinate The <br /> depth to static groundwater is measured from a set location at the top of the PVC casing The <br /> depth of water is then subtracted from the elevation of the top of the well casing to provide a <br /> groundwater elevation for each monitoring well location <br /> A-4 GROUNDWATER MONITORING <br /> A-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 /> 2 The water level probe is decontaminated in a tnsodium phosphate wash, followed by a <br /> distilled water rinse, prior to use in each well <br /> 3 Water level measurements are made using a conductivity-based water-level meter <br /> Depth-to-water is generally measured from a surveyed mark on the north nm of the <br /> PVC well casing <br /> The water level measurements are converted to elevations using the surveyed casing elevations <br /> A-4 2 Groundwater Sampling <br /> Groundwater samples are collected from the monitoring wells at the site The sampling <br /> protocol for each well is as follows <br /> 1 Down-well equipment (pumps, bailers, etc ) is decontaminated by steam cleaning, or <br /> by scrubbing in a trsodium-phosphate wash followed by a distilled water rinse, prior to <br /> use in each well Bailer cord is replaced prior to use in each well <br /> 2 The depth-to-water is measured using a conductivity-based water-level meter <br /> SAPROTO(1993) Page A-4 <br /> 24-160241-000 <br /> Copyright 1993 Kleinfelder, Inc <br />