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Work Plan For Monitoring Well Installation — Former Chevron Service Station 49-5775, Lodi, CA <br />April 7, 2000 <br />Of the three proposed on-site monitoring wells, one of the wells at the northeast corner of the site <br />and the well next to MW -5 will be drilled to 90 feet bgs, and the other well at the northeast corner <br />of the site will be drilled to 65 feet bgs. The two proposed off-site wells located south of well <br />MW -9 will be drilled to 65 and 90 feet bgs, and the proposed off-site well next to MW -8 will be <br />drilled to 90 feet bgs. All wells will be drilled with 8 -inch diameter hollow -stem augers, and will <br />be constructed with 2 -inch diameter Schedule 40 polyvinyl chloride (PVC) well casing and <br />0.02 -inch machine slotted well screen. The wells drilled to 65 feet bgs will have 20 feet of screen <br />extending from 45 to 65 feet bgs, and the wells drilled to 90 feet bgs will be screened from 85 to <br />90 feet bgs. Proposed groundwater monitoring well construction details are shown on Figures 4 <br />and 5. <br />Over the intervals described above that will be sampled and logged, soil samples for description <br />and possible chemical analysis will be obtained from the borings at five-foot intervals, as a <br />minimum. Soil samples will be collected with a split -spoon sampler fitted with clean brass <br />sample rings. The actual number of samples submitted for chemical analysis will depend on site <br />conditions and field screening data. At a minimum, one soil sample will be submitted for <br />chemical analysis as described in Task 5. <br />Soil from each sampled interval will be screened in the field for the presence of volatile organic <br />compounds using a photoionization detector (PID). These data will be collected for <br />reconnaissance purposes only, and will not be used as verification of the presence or absence of <br />petroleum hydrocarbons. <br />Drill cuttings will be stored at the site pending receipt of disposal characterization data. The drill <br />cuttings will be stockpiled on and covered with plastic sheeting. Four discrete soil samples will <br />be collected from the drill cuttings for disposal characterization as described in Appendix A. <br />These samples will be submitted to the laboratory for compositing and analysis as described in <br />Task 5. Stockpiled soil will be transported to an appropriately licensed facility by Integrated <br />Wastestream Management (IWM). Steam cleaning rinsate waste water will be transported by <br />IWM to McKittrick Waste Management. <br />Task 3. Well Development and Sampling <br />The newly installed groundwater monitoring wells will be developed after being allowed to stand <br />a minimum of 72 hours following completion. During development, the clarity of the discharged <br />well water and selected groundwater parameters (pH, temperature, conductivity) will be <br />monitored. When the discharge water runs clear and the groundwater parameters have stabilized, <br />a groundwater sample will be collected from each well. The groundwater samples will be <br />analyzed as described in Task 5. Groundwater removed from the well during development and <br />sampling will be transported by IWM to McKittrick Waste Management. <br />Task 4. Wellhead Survey <br />Following installation, the top of casing elevations for the new wells will be surveyed to mean sea <br />level by a California licensed surveyor. Horizontal coordinates of all well locations will also be <br />obtained by the surveyor. <br />346408.09 <br />