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C1,EARWATER CI R () U -011 1 N C 4.0 TEST WELL INSTALLATION 4.1 Groundwater Extraction Well Installation Clearwater will supervise the installation of a single groundwater extraction well in the locations shown on Figure 2 Mitchell Drilling Environmental of Rancho Cordova, California has been selected to provide the contracted drilling services The boring for the monitoring well will be advanced with standard 10-inch outside diameter hollow stem augers driven by a truck mounted drilling rig RThe boring will be advanced to a depth of 30 feet below ground surface The groundwater extraction well will be constructed with clean, 4-inch diameter, flush threaded, Schedule 40, polyvinyl chloride (PVC) blank casing from the ground surface to 10 feet bgs and 0 020-inch slotted casing from 10 to 30 feet bgs The annular space through the screened interval will be filled with clean uniform sand to a depth of 8 feet (two foot above the screen) A two-foot thick hydrated bentonite seal will be placed above the sandpack, and the annular space above the seal will be filled with grout The top of the well casing will be capped above grade and locked with ' an expansion plug The dimensions of well construction as described above are approximate and may vary according to conditions in the field One soil sample will be collected during installation of the groundwater extraction well to assess the soil properties and the presence and concentration of indigenous bacteria in the vicinity of the former underground tanks This sample will be analyzed for total petroleum hydrocarbons as gasoline (TPHg), as diesel (TPHd), benzene, toluene, ethylbenzene, and xylene isomers (BTEX), moisture content, pH and for Hydrocarbon Utilizing Bacteria, according to ASTM Method G22 The sample will be collected from the interval immediately above the water saturated zone The well will be developed using a combination of surging and bailing Development will proceed until the ground water being removed is relatively free of turbidity All downhole drilling equipment will be steam cleaned and the rmseate will be stored on site in labeled 55 gallon drums Soil generated from drilling activities will be stockpiled on site Rmseate and stockpiled soil will be removed for disposal from the site following required profiling by a licensed waste hauler Clearwater's well installation and development protocols are presented in Appendix A. ' 4.2 Air Sparge Well. Installation Clearwater will supervise the installation of two air sparging wells at the locations shown on Figure 2. The borings will be advanced to approximately 10 feet below the static ground water level in each well and terminated at that depth The anticipated . depth of each boring is 25 feet bgs The wells will be constructed with clean, 2-inch D-107/PILOT TEST WP 2 t