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r� <br /> Between sampling events, sampling equipment was cleaned using a three-bucket wash system. <br /> In this system, the rings and samplers are scrubbed with a brush in a bucket of tap water and <br /> detergent, rinsed in a second bucket of tap water and given a final rinse in a bucket of distilled <br /> water. <br /> 5.2 Monitoring Well Installation <br /> All borings were advanced approximately 15 feet beyond static groundwater and converted to <br /> monitoring wells by the installation of 25 feet of 0 010 slotted PVC screen with casing to the <br /> surface. Groundwater was first detected during drilling of monitoring well MW 1 at 64.57 feet <br /> below grade and stabilized at 62.5 feet. In well MW2 initial groundwater was detected at 63 <br /> feet below grade and stabilized at 6173 feet. In well MW3 groundwater was initially detected <br /> at 62 feet below grade and stabilized at 60.19 feet. <br /> All wells were constructed of 2-inch diameter, flush-threaded, schedule 40 PVC screen and <br /> casing. Typical monitoring well construction details are shown in Figure 6. Wells were filter <br /> packed using #2 silica sand, a two-foot thick bentonite seal placed above the filter pack and then <br /> an annular seal of neat cement was tremmied into place. Wells were completed below grade in <br /> water-tight, street-rated well protectors All wells were fitted with water-tight, locking caps for <br /> security purposes. Completion depth for each well was approximately 77 feet below grade. All <br /> r <br /> procedures and protocol for groundwater monitoring well construction conform to the standards <br /> set by the California Department of Water Resources and the Regional Water Quality Control <br /> _ Board (RWQCB). San Joaquin County Public Health Services witnessed the placement of the <br /> r annular seal. <br /> E <br /> Following installation, monitoring wells were developed using swab and bail method. <br /> Development water was containenzed in DOT 17H drums and stored on site pending <br /> determination of proper disposal method. <br /> The top, north side of the well casing was surveyed relative to a common datum for,determining <br /> groundwater gradient information. Surveying was performed under the direct supervision of <br /> Nora H. Kataoka, California Registered Civil Engineer No 38322 Groundwater contours were <br /> L ,� - 4 <br />