The purpose of this project is to fill a data gap in the current groundwater monitoring network and act as a sentinel well for detection of potential PFAs (per- and polyfluoroalkyl substances) contamination prior to it reaching Zone 7’s Hopyard Wellfield.
This project involves drilling an exploratory boring to 800 feet below ground surface (bgs) and running a geophysical log to assess the lithology. Two 2-inch diameter PVC wells will be constructed within the exploratory boring at depths based on the lithology encountered. The work will be completed by a C-57 licensed driller using mud rotary drilling techniques. A support truck, mud shaker, and watertight roll-off bin to contain spoils will also be used during construction. The approximate amount of space needed for the job is 120 feet by 120 feet. After the wells are constructed, they will be developed to ensure communication with the aquifer. Each well in the nest will be fitted with a locking cap. The final well completion will consist of an approximately 18-inch diameter traffic rated cover that will be installed flush with the surrounding parking lot.
Zone 7 staff are coordinating with the City of Pleasanton parks department staff to minimize any inconvenience for public use of the park facilities. This includes coordination of set work areas, staging areas, and work hours. The park is adjacent to a residential neighborhood. The project will abide by the local noise ordinance and strict work start and stop times will be enforced.
The work is expected to take place around April 2023. Construction period should be about 21 days.