UC Merced

The Sustainable Groundwater Management Act (SGMA), enacted in 2014, serves as California’s first foray into establishing a comprehensive groundwater management program. Under this legislation, basins are required to mitigate groundwater overdraft to reach sustainable conditions by 2040 or 2042. Reductions in groundwater pumping are anticipated to drive substantial shifts in the San Joaquin Valley’s agricultural sector, which has historically depended on groundwater to provide water for irrigation. This research examines a case study of SGMA implementation in the Kings and Tulare Lake groundwater basins, focusing on potential impacts for agricultural land cover and economics. Publicly available information on spatial cropping patterns, irrigation requirements, and crop production economics as well as overdraft information and historical water availability from Groundwater Sustainability Plans (GSPs) are used to calibrate a hydroeconomic agricultural production optimization model representing the agriculture in the study area. Scenarios integrating overdraft responsibilities with options for surface water trading and groundwater supply augmentation through recharge are modeled to explore potential outcomes for future agriculture under SGMA. Results suggest ranges and distributions for land fallowing and losses of agricultural revenue under a variety of possible scenarios. Findings also highlight the importance of water trading and groundwater recharge programs in meeting sustainability in the basins and barriers to implementing these programs are discussed.