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• DDJOTacy OU 1 Pesticide Remediation Groundwater Piezometer Abandonment and Installation Work Plan approximately 10 feet from the original location, • Reference elevation for all depth measure- and a new piezometer constructed. ments; 3.0 PIEZOMETER INSTALLATION • Name of driller; ACTIVITIES • Name and signature of the field geologist 3.1 Six of the 10 temporary piezometers were preparing the log;and recommended to be reinstalled as permanent piezometers,TPZI,TPZ2,TPZ4,TPZ7,TPZ9, • Name and signature of California registered and TPZ10(URS, 2004b).Upon reinstallation, geologist who provided oversight. each permanent piezometer will be assigned a new piezometer number. 3.4 The field geologist will record an as-built diagram of each piezometer during the con- 3.2 A hollow-stem auger drill rig will be used struction.The type of information that will be to construct 1-inch-inside-diameter piezometers included in the log is discussed in the DDJC- with the materials described in the following SharpelTracy Comprehensive Field Work Plan paragraphs. Screen intervals of the piezometers Field Procedures(URS,2004c). will be determined using lithologic data obtained from continuous coring of EW047AU and 4.0 PIEZOMETER MATERIALS EW048AU,which were drilled to approximately 60 feet below ground surface(bgs). 4.1 Piezometer Casing 3.3 The URS field geologist will maintain an The piezometer casing will be 1-inch-inside- accurate log for each boring drilled.At a diameter Schedule 40 polyvinyl chloride(PVC) minimum,the log shall include: pipe with flush threads.The casing surface will be free of solvents, oils,grease,paint,and dirt • Name of the project and site; and will be certified clean from the factory or steam-cleaned on site prior to installation. • Boring number; Sections of casing will be received from the supplier wrapped in polyethylene protective • Date drilled; wrappers with sealed ends to limit exposure to potential contaminants.Casing will not be • Location of the boring; removed from the wrapping until immediately before it is to be placed in the boring. • Type of drill rig; 4.2 Piezometer Screen • Size and type of drilling method used; Each piezometer screen will consist of a 1-inch- • Depth at which groundwater was first nominal-diameter, Schedule 40 PVC continuous encountered; slot screen with flush threads.All screen openings will widen inward so as to be non- • Depth to the static water level and changes clogging.The precise screen depth and slot size in static water level with hole depth; will be determined based on the lithology encountered during the drilling of the piezome- • Total depth of the hole; tens.The screen will be of sufficient size and design to hold back and support the filter pack • Depth or location of any problems and in situ soils surrounding the screen.The well encountered(i.e.,heaving sands); screen surface will be free of solvents,oils, grease,paint, and dirt and will be certified clean • Lithologies of soil layers encountered; from the factory or steam-cleaned on site KAWpnxess\00701\Trecy\0UJ Pst PZ Abnd\DRAFntext.dm 2 June 2004