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I staff under the direction of a California Professional Geologist using the Unified Soil Classification System. All downhole equipment will be decontaminated prior to use. The screen intervals and total piezometer depths will be determined in the field based on geologic logging and the depth to first encountered groundwater. When the first wet cuttings are observed the drill casing will be pulled up to allow groundwater to enter the boring. The depth to water in the boring will then be measured. The depth of the first encountered groundwater will be used to determine the screen interval for each piezometer, and the screen length will not exceed 15 feet in length. Pending approval by the SJCEHD, the top of the screen interval will be set at a depth no shallower than 7 feet bgs to allow the placement of a minimum 5-foot surface seal. The piezometers will be constructed through the drilling casing and will consist of 2-inch nominal diameter, Schedule 40 polyvinyl chloride (PVC) pipe, with 0.020-inch factory- cut, slotted well screen, flush-threaded joints and a bottom cap. The outside boring diameter of the piezometers will be at least four inches greater than the outside diameter of the piezometer casings. The annular space between the borehole wall and well screen will be filled with Lapis-Lustre#3 filter pack sand to a depth of about 2 to 3 feet above the top of the well screen. Approximately 2 to 3 feet of bentonite chips or pellets will be placed above the sand pack and hydrated to provide a seal above the filter pack. The remainder of the borehole will be tremmie filled with a Portland Type 11-V cement grout to the ground surface.Dependent on the piezometer location,the surface completions will either consist of flush mounted traffic rated well boxes or above ground stove-pipe completions with bollards.The CVRWQCB will be notified in advance if the piezometer construction will be different from the specifications listed above. The piezometers are intended to be used for water level monitoring only and therefore are not planned to be developed. After construction, the piezometers will be surveyed by a California-licensed surveyor,including top of casing elevations and northing and easting coordinates,and the boring logs and survey information will be uploaded to GeoTracker. 4. SCHEDULE Installation of the piezometers will be completed as soon as possible after receiving approval of this Work Plan by the CVRWQCB, receiving piezometer installation permits from SJCEHD, and securing an installation date with a C-57 licensed drilling subcontractor. A piezometer installation report will be submitted to the CVRWQCB within 45 days of completing the field activities. 2