Jeffrey Mount

Jeffrey Mount, Ph.D. (Northern California)

Senior Fellow, Public Policy Institute of California Water Policy Center
Professor Emeritus, Department of Earth and Planetary Sciences at University of California, Davis

The Consequences of Groundwater Sustainability in California


In 2014 California enacted the Sustainable Groundwater Management Act (SGMA) to address impacts associated groundwater pumping. This act mandates that areas that depend upon groundwater achieve sustainability by 2040. To meet the requirements of this act there will need to be a net reduction in groundwater overdraft of more than 2 million acre-feet per year. The social, economic and environmental consequences—intended or otherwise—of this change in water policy are vast. Opportunities to augment supplies are limited, although new storage, conveyance and groundwater recharge will help. In areas connected to the state’s water supply systems—particularly the federal Central Valley Project and the State Water Project--there will be increased pressure to transfer water. This will impact on-going efforts to address water supply reliability and ecosystem issues in the Sacramento-San Joaquin Delta. However, sustainability will be achieved principally though reductions in demand. In the San Joaquin Valley—the region accounting for most overdraft—this will involve permanent or temporary fallowing of hundreds of thousands of acres of farmland, with consequences for the farm economy in the valley and rural communities dependent upon farm labor. There will also be wide ranging environmental consequences. How land is fallowed, including the quality of soils, will affect air quality, water quality and terrestrial habitat. Demand reduction will also increase conflicts over the use of surface water to support aquatic habitat and wetlands as well as groundwater-dependent ecosystems. California needs to take a comprehensive look at what it is going to take to achieve groundwater sustainability and develop pathways that minimize or mitigate unwanted effects.


Dr. Jeffrey Mount is a Senior Fellow with the Public Policy Institute of California Water Policy Center. He is the Founding Director of the UC Davis Center for Watershed Sciences and Professor Emeritus in the Department of Earth and Planetary Sciences. While at UC Davis he held the Roy Shlemon Chair in Applied Geosciences and UC President’s Chair in Undergraduate Education.

During his long career Dr. Mount has published widely on the science and management of rivers, including his award-winning book, California Rivers and Streams (UC Press). He is co-author of the recent synthesis Managing California’s Water: From Conflict to Reconciliation (Public Policy Institute of California). His work at the Public Policy Institute of California focuses on bringing together multidisciplinary teams of researchers to develop novel solutions to water problems, particularly in California.