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• DDJC-Sharpe EWCC39ometer Installation Wor Plan <br /> Table 3-1. Estimated Piezometer Specifications* <br /> Estimated Estimated <br /> Aquifer Screen Casing Casing Well Slot Length of <br /> Zone Depth Diameter Material Screen Material Size Well Scr en <br /> Upper C 100-110 2-inch ID Schedule 80 Continuous Slot 0.020 5 feet <br /> Zone feet bgs PVC Schedule 80 PVC <br /> C Zone 125-135 2-inch ID Schedule 80 Continuous Slot 0.020 5 feet <br /> (EWCC3) feet bgs PVC Schedule 80 PVC <br /> Lower C 160-170 2-inch ID Schedule 80 Continuous Slot 0.020 5 feet <br /> Zone feet bgs PVC Schedule 80 PVC <br /> * Each piezometer nest(PPZ00l—PPZ003)will contain three piezometers;construction specifications are dependent upc n the <br /> lithology encountered during drilling. <br /> bgs = below ground surface <br /> ID = inside diameter <br /> PPZ = proposed piezometer <br /> PVC = polyvinyl chloride <br /> 4.3 Filter Pack for the installation of the bentonite seal are <br /> presented in the DDJC-Sharpe/Tracy Com re- <br /> The filter pack material will be composed of hensive Field Work Plan(URS, 2001b). <br /> round,hard, water-worn siliceous sand,free of <br /> flat or elongated pieces, organic matter, or other 4.5 Cement Grout <br /> foreign matter. All filter pack material will be <br /> protected from contamination prior to placement A cement grout will be used to fill the annu ar <br /> by either storing it in plastic-lined paper bags or space above the hydrated bentonite seal. Ce rient <br /> in a location protected from the weather and grout will consist of Type II Portland cemei it <br /> contamination on plastic sheeting. All filter pack with 3 pounds of powdered nonbeneftciate <br /> material will be placed in the annular space in bentonite and 7 gallons of water per 94-pou id <br /> the borehole by using a 2-inch tremie pipe. Once sack of cement. The cement grout will be <br /> the filter pack is in place,the driller will develop mechanically mixed with a paddle type mix r <br /> the interval until no measurable decline in the and then tremied in place. No accelerator w Il be <br /> filter pack is measured. All water placed into the added to the grout. Guidelines that are to be used <br /> borehole during the construction process will be for the installation of the grout seal are pres nted <br /> accounted for and removed before the well is in the DDJC-Sharpe/Tracy Comprehensive <br /> developed. A complete description of the guide- Field Work Plan (URS, 2001b). <br /> lines that are to be used for the installation of <br /> filter pack material is presented in the DDJC- 4.6 Wellheads <br /> Sharpe/Tracy Comprehensive Field Work Plan <br /> (URS, 2001b). Once the grout seal in each piezometer nests has <br /> been tremied into place and time has elapsed to <br /> 4.4 Bentonite Seal allow for the grout to cure, a water tight, fl h- <br /> mounted (i.e., at street level)utility box will be <br /> Each piezometer nest will be constructed with a placed over the top of each piezometer nest The <br /> bentonite seal placed above the filter pack to three piezometers within each nest will have <br /> protect the filter pack during grouting. The brass tags affixed to the tops of the casings <br /> bentonite seal will consist of bentonite pellets or indicating the piezometer numbers. <br /> chips. Once the seal is in place,the interval will <br /> be hydrated for a minimum of 30 minutes before <br /> grouting occurs. Guidelines that are to be used <br /> K912200\Sharpe\EW CC3 Piez WP\EWCC3 WP.doc 4 Jul2002 <br />