United Water Conservation District (United) proposes to implement the Information Collection for the Proposed Extraction Barrier and Brackish Water Project (Project), which will consist of land surveying, geotechnical exploration and technical information collection through hydrogeology, environmental (e.g., biological, cultural, paleontological), engineering, underground utility location and marking, and traffic control site surveys. Information collection may include additional specialists/ consultants and contractors; however, in any case, the surveys will involve no disturbances beyond these non-invasive components. The Project will also involve the construction of up to six (6) nests or clusters of up to four (4) monitoring wells each at Naval Base Ventura County (NBVC) Point Mugu to collect groundwater quality and level data in the semi-perched aquifer (up to 150 feet deep) and Oxnard aquifer (up to 250 feet deep) and may include deeper completions in the Mugu aquifer (up to 350 feet deep) or Fox Canyon aquifer (up to 800 feet deep). The monitoring wells will support groundwater sampling to document constituents in the unconfined and confined (target) aquifers in the Project area and create a groundwater quality baseline for comparison with future groundwater sampling results. The new monitoring wells are intended to confirm isolation of the waters of the semi-perched aquifer from the underlying confined aquifers under pumping conditions. Monitoring wells will be equipped with pressure transducers and data loggers. The timing of monitoring well installation will be between May 24 and November 7, 2023. Once installed, monitoring wells will be sampled on a routine basis.
The Project will also include geophysical and geotechnical investigations, which will be informed by the data collected during monitoring well installation. The technique and transect locations are currently undetermined but will likely involve electrical resistivity techniques. Seismic reflection will likely not be a good option, but specific investigation methods will be determined with data collected during monitoring well drilling. Some minor ground disturbing activities will likely be needed in order to implement the geophysical study; however, these activities will occur in disturbed areas associated with NBVC Point Mugu.