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- ------ ----- KLEINFEL€JEP <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 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 />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 />B4.2 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-YP 1 -611 /2011 P 181 Page B-6 <br />Copyright 2001, Kleinfelder, Inc. July 3, 2001 <br />