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WaterWork <br />Groundwater Monitoring Protocol <br />Monitoring depth to water and free product thickness within wells <br />at the site will be conducted using an Interface Probe and <br />Surface Sampler. The Interface Probe is a hand held, battery <br />operated device for measuring depth to petroleum product and <br />depth to water as measured from an established datum (i.e., top <br />of the well casing which has been surveyed). For consistency, <br />all measurements will be taken form the north side of the <br />wellhead. To assess potential infiltration of fine grained <br />sedimen-s, well depth will be sounded using the interface probe. <br />Product thickness is calculated by subtracting the depth to <br />product from the depth to water. In addition, water elevations <br />are adjusted for the presence of fuel with the following <br />calculation: <br />(Product Thickness) (.8)+(Water Elevation) <br />= Corrected Water Elevation <br />Note: The factor of 0.8 accounts for -_he density difference <br />between water and petroleum hydrocarbons. <br />An acrylic Surface Sampler shall be used for visual inspection of <br />the groundwater to note sheens (difficult to detect with the <br />Interface Probe), odors, microbial action and sediments. The <br />sampler is calibrated in inches and centimeters for visual <br />inspection of product thickness. <br />To reduce the potential for cross contamination between wells, <br />the monitorings will take place in order from the least to most <br />contaminated. Wells containing free product will be monitored <br />last. Between each monitoring the equipment will be washed with <br />laboratory grade detergent and double rinsed with tap water, and <br />final rinsed with deionized water. <br />