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• k'9 KLEINFELDER <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 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 .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 (usually <br /> the north rim). The depth of water is then subtracted from the elevation of the top of the well <br /> casing to provide a groundwater elevation for each monitoring well location. <br /> B-4 GROUNDWATER MONITORING <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 water level probe is decontaminated in a trisodium phosphate or non-phosphate <br /> detergent wash, followed by a distilled water rinse,prior to use in each well. <br /> 2. 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 rim of the PVC <br /> well casing. <br /> The water level measurements are converted to elevations using the surveyed casing elevations. <br /> B-4.2 Groundwater Sampling <br /> Groundwater samples are collected from the monitoring wells at the site. The sampling protocol <br /> for each well is as follows: <br /> 1. Down-well equipment (pumps, bailers, etc.) is decontaminated by steam cleaning, or by <br /> scrubbing in a trisodium-phosphate or non-phosphate detergent wash followed by a <br /> distilled water rinse, prior to use in each well. Bailer cord is replaced prior to use in each <br /> well. <br /> 2. The depth to groundwater is measured using a conductivity-based water-level meter. <br /> 3. The volume of water in gallons standing in the well is calculated by subtracting the depth <br /> to groundwater measurement from the depth of the well and multiplying by the <br /> appropriate conversion factor(0.16 for 2-inch wells, and 0.65 for 4-inch wells). <br /> 4. Three to five well volumes of water are purged from each well using a submersible pump, <br /> bladder pump, or Teflon bailer. <br /> 20-YP9-278/2019P314/2019W028 Page B-6 <br /> Copyright 1999,Kleinfelder, Inc. October 27, 1999 <br />