COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

Geosyntec° consultants screens. Following surging, several bailers of water will be withdrawn from the well casings to remove sediment that may have entered the casings. An approximately 5-foot-thick layer of#30 transition sand will be installed above the top of the filter pack to act as a buffer between the filter pack material and the overlying bentonite seal. An approximately 5-foot-thick annular seal of bentonite pellets will then be installed above the transition sand. Above the bentonite seal,the annular space between the well casing and borehole wall will be filled with neat cement slurry with up to 5% bentonite to the ground surface in accordance with county and state requirements. The wells will be initially installed with temporary above ground stovepipe surface completions until the permanent wellhead and pump are installed as part of the conveyance system. The top of the well casings will be fitted with locking expandable-gasket caps until the wellheads are installed. 5.1.3 Survey Upon completion of well installation activities, the well locations and top of casing elevations will be surveyed by a State of California Licensed Land Surveyor using a global positioning survey instrument. The survey will be referenced to a recognized survey monument. The top of casing elevation (north face) will be surveyed to 0.01-foot accuracy. The top of casing elevation of the extraction wells will be re-surveyed after the permanent wellheads are installed. 5.2 Well Development, Hydraulic Testing, Sampling and Analysis 5.2.1 Well Development Well development will be conducted at EW-18A, EW-1813, and EW-19 to establish better hydraulic communication with groundwater in the surrounding formation. After allowing at least 48 hours for the grout seal to set,the well will be developed using a combination of bailing, swabbing, air lifting, and pumping. Well development will be implemented to remove drilling mud, fine-grained materials from inside the filter pack and casing, and to stabilize the filter pack around the well screen. The static water level will be measured prior to well development. Initially, water will be bailed from the well to remove sediment that settled to the bottom during well installation. Swabbing will then be performed incrementally over the screen interval starting at the base of the screen interval and finishing at the top of the screen interval. Bailing will be used to remove sediment that accumulates in the well during swabbing. After swabbing is completed, air-lifting will be conducted in the well. A temporary submersible pump will be installed in the extraction well with the capacity to produce a range of flows up to at least 200 gallons per minute (gpm). Pumping will be initiated and the flow rate will be varied. During each pumping interval, drawdown will be measured to evaluate changes in the well-specific capacity as development proceeds. Groundwater quality parameters (temperature, pH, specific conductance, and turbidity)will be measured. Extraction Well Installation Work Plan 6 November 30,2018