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• DDJC-Sharpe EWCC3*ometer Installation Worc Plan • Name and signature of the field geologist 4.0 PIEZOMETER MATERIALS preparing the log; and 4.1 Piezometer Casing • Name and signature of California registered geologist who provided oversight. The piezometer casing will be 2-inch inside diameter Schedule 80 polyvinyl chloride(P C) 2.2.2 During the construction of each piezome- pipe with flush threads.During installation,PVC ter,an as-built diagram of each piezometer nest spacers(see Attachment A design drawing)will will be recorded by the field geologist. Further- be placed between the three piezometers an more,a detailed log will be kept during the affixed with plastic ties; these will assure that development of each piezometer.The type of the PVC casing will be separated during in alla- information that shall be included in each of tion of the filter pack, bentonite seal, and grout. these logs is discussed in the DDJC-Sharpe/ The casing surface will be free of solvents, ils, Tracy Comprehensive Field Work Plan (URS, grease,paint, and dirt and will be certified clean 2001b). from the factory or steam-cleaned on site prior to installation. Sections of casing will be 2.3 Drilling Requirements received from the supplier wrapped in polyethy- lene protective wrappers with sealed ends i For all three proposed piezometer nests, 12-inch order to limit exposure to potential contami diameter borings will be drilled using a mud nants. Casing will not be removed from the rotary drilling rig;continuous core for lithologic wrapping until immediately before it is to b logging will be obtained through the targeted placed in the boring. sand zones.Mud rotary drilling is preferable over hollow-stem auger drilling at depths 4.2 Piezometer Screen exceeding 100 feet bgs due to the potential for heaving sands and the difficulty in controlling Each piezometer screen will be 2-inch insid these sands using augers. Upon completion of diameter,continuous slot Schedule 80 PVC with drilling and logging, three 2-inch diameter flush threads. All screen openings will widen piezometers will be installed at different depth inward so as to be non-clogging. The slot si re intervals within each boring(i.e., in sandy zones will be compatible with the filter pack that will at approximately 110 to 120 feet bgs, 125 to 135 surround the screen; slot size and filter pacli will feet bgs [EWCC3 interval], and 160 to 170 feet be determined based on pilot boring litholo ies. bgs). Additional detail regarding the mud rotary The piezometer screen will be of sufficient ize method of drilling is included in the DDJC- and design to hold back and support the flit r Sharpe/Tracy Comprehensive Field Work Plan pack and in situ soils surrounding the screen. (URS,2001b). The piezometer screen surface will be free f solvents, oils, grease,paint, and dirt and wi]1 be 3.0 PIEZOMETER certified clean from the factory or steam-cle ned SPECIFICATIONS on site prior to installation.The piezometer screen will have smooth, sharp-edged openi igs Each of the three nested piezometers will be free of burrs,chipped edges, or broken piec s on installed using the guidelines set forth in the the interior and exterior surfaces of the pipe DDJC-Sharpe/Tracy Comprehensive Field Work Sections of the screen will be received from the Plan(URS, 2001b). The estimated design speci- supplier wrapped in polyethylene protective fications of the proposed three piezometer nests wrappers with sealed ends in order to limit are shown in Table 3-1. A diagram of a typical exposure to potential contaminants. Wrapping groundwater piezometer nest design is included will not be removed until screen is to be use . in Attachment A to this work plan. KAI2200\Sharpe\EW CC3 Piez WP\EWCC3 WP.dm 3 Jul 2002