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• • • 2. Proposed Monitoring Well Locations • • Based on the southerly direction of groundwater flow, the new upgradient well (MW-10) • will be located immediately north of ponds P-1 and P-2, while the down-gradient wel1ow-11 will be located immediately south(see Figure 4). The specific locations within the 11 • containment berms will be selected to provide vehicle access, as well as convenient • access for sample collection and groundwater level monitoring. • B. DRILLING DETAILS • • This selection provides a description of the equipment that will be used to construct the • monitoring wells, along with associated drilling activities. • 1. Drilling Equipment • The wells will be drilled using a hollow-stem auger. The drilling contractor will be • required to hold a valid Class C-57 California Contractor's License. A permit for installation of the wells will be obtained from the San Joaquin County Environmental • Health Department. The borehole will be drilled until groundwater is encountered,plus a • maximum of approximately 20 ft. Based on a berm elevation of 100 ft and the • groundwater elevations presented in Figures 2 and 3, it is expected that the boreholes will be from 40 to 50 feet deep. The well borehole will be approximately 12 inches in • diameter, to allow for adequate space for the gravel pack and well casing. All cuttings • will be disposed of by spreading onsite. Drilling equipment will be washed at each • monitoring well site to avoid soil cross-contamination. Well casings will be inspected to • ensure they are clean when installed. • 2. Well Installation Activities • The well boring will be logged under the direct supervision of a professional geologist. • As determined by the geologist, analyses will be conducted on selected formation • samples (typically every five feet). The well log will include the general character, type, • and depths of materials penetrated, and any pertinent observations on the depths of water- bearing horizons, or other data that may assist in the interpretation of the subsurface geology. • As part of the log, the geologist will accurately determine the depth from which cuttings • and fluid samples are taken for analysis. A well installation report will be included with the log and will show,by depth, the bottom of the boring, screen location, granular • backfill, seals, grout, cave-in, and height of protective casing above ground surface. The • actual composition of the granular backfill, seals, and grout will be recorded on the well • detail. The well log sketch will include the protective casing detail, details on the size and type of screen used, and centralizer design (if used). Any variations in the proposed • well design will be noted, with the depths at which such changes are required. • • • • Riverbank WWTP Workplan Nolte Associates,Inc. • March 2005 2 \\SasO\project\SA1542\mon_well\new\gwmwiwp\wp.doc •