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A-3.5 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 ground water 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 /> ground water elevation for each monitoring well location. <br /> A-4.0 COLLECTION HYDROPUNCH II° GROUNDWATER SAMPLES <br /> One-time groundwater samples are collected using a Hydropunch II°, which is an in situ <br /> groundwater sampling device. The borings will be advanced to a depth equivalent to the <br /> bottom of the capillary fringe. A stainless steel drive tip equipped with a filter is lowered into <br /> the borings at the end of a 2.5-inch diameter galvanized steel pipe and pushed using the drill <br /> rig approximately 3 to 5 feet into the soil/aquifer formation at the bottom of the boring. A <br /> thoroughly decontaminated bailer can then be lowered down the center of the Hydropunch II° <br /> casing to obtain a sample of groundwater (which has entered the Hydropunch ll° due to <br /> hydrostatic pressure). <br /> To reduce the potential of introducing contaminants into the samples, the drive tip, galvanized <br /> pipe, and other equipment used for sample collection are steam cleaned and/or washed with <br /> trisodium phosphate (TSP) solution and rinsed with distilled water prior to use. The sample <br /> tips and filters are not retrievable. New O-rings, tips, and screens are used for each sample. <br /> 117226.E02/ST013R0176 Page A-6 January 31, 2013 <br /> Copyright 2013 Kleinfelder <br />