Location: Sustainable Agricultural Water Systems Research
Project Number: 2032-13220-002-028-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2024
End Date: Aug 31, 2026
Objective:
The objective is to image spatial and temporal changes in water content in the vadose zone in the Central Valley of California induced by managed and natural aquifer recharge processes at the surface and shallow subsurface.
Approach:
Managed aquifer recharge (MAR) is a potentially useful method for replenishing depleted aquifers in California's Central Valley, but the efficacy of recharge operations is not well understood. It is especially challenging to assess the flow of recharge water through the unsaturated (vadose) zone at great depth (>50 m depth). State-of-the-art sensors such as borehole nuclear magnetic resonance (NMR) can assess MAR efficacy over time using existing deep monitoring well infrastructure. A key component of this project will be to identify monitoring wells in the Central Valley as test locations to validate the NMR monitoring approach. NMR logs will be acquired on a regular basis (semiweekly to monthly) in order to assess how the distribution of water changes in the vadose zone under a range of external forcing conditions. such as active recharge operations and natural hydrologic processes. The results of these studies will be useful for constraining estimates of MAR efficiency in the Central Valley.
