Impact of Precipitation and Managed Aquifer Recharge on Post-Drought Groundwater Storage Recovery in California's Central Valley

Water scarcity is a critical global challenge, and understanding how groundwater in aquifers recovers from prolonged droughts is essential for sustainable water resource management. In California's Central Valley, a crucial agricultural hub facing groundwater depletion, this research explores the contribution of large rainfall events associated with Atmospheric Rivers and El Nino to groundwater depletion and recovery. Additionally, it examines Managed Aquifer Recharge (MAR) as a strategic solution to the groundwater depletion issue. This research aims to enhance groundwater resilience and mitigate flooding risks, aligning with California's recent Sustainable Groundwater Management Act (SGMA). Anticipated outcomes, such as groundwater storage maps under diverse climate scenarios, provide invaluable tools for prioritizing MAR implementation and facilitating decision-making within the SGMA framework. The project also trains a Ph.D. student in sustainable water resources management and enriches water resources curricula at UCLA through the inclusion of project datasets, models, and scenarios. The project addressed two main research questions. The first question explores the impact of precipitation trends on groundwater drought recovery. The approach integrates historical data analysis and computer model simulations. Research tasks include identifying relationships between annual and seasonal groundwater recovery and precipitation and assessing the influence of precipitation characteristics on recovery. The second question investigates the potential of MAR in increasing aquifer resiliency. The approach utilizes numerical experiments using a computer model to simulate groundwater storage recovery under various climate scenarios and MAR implementations. The results will provide insights into the effectiveness of MAR in mitigating groundwater overdrafts, with implications for low-flow augmentation and flood risk reduction. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.