California’s prolonged drought has driven home the need to improve our balance sheet for water – determining how much there is, who has claims to it and what is actually being used.
Our research, which was released Wednesday, has identified major gaps in the collection, management and use of water information. Compared to 11 other western states, Australia and Spain – places that also struggle with water scarcity – California’s systems have significant room for improvement.
One of the biggest challenges is accounting for groundwater, which supplies about one-third of agricultural and urban water use in normal years, and as much as 60 percent during the current drought.
The good news is that the work has begun. Under a landmark 2014 law, California now requires groundwater basins to be managed sustainably.
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The bad news is that achieving comprehensive accounting systems for groundwater will be a heavy lift. Water pumped from most wells is not consistently measured, monitored or reported. The new law puts the reins in the hands of local officials, which harnesses local knowledge and creativity, but also risks creating chaos and fostering costly litigation.
Farmers, irrigation districts and urban water utilities will need to work together to recharge more water into basins and pump less out of them. The state can play a key role in making this task easier.
California can have a common system of water accounting standards, for example on units and frequency of measurement, so local agencies can manage and share information. Australia, which pioneered water accounting standards, does this especially well.
The state can also develop standards for computer models that are needed to estimate how much groundwater each basin holds and how much water moves within and across basins. Many local agencies have incentives to use customized models, but that invites conflict. At a minimum, California needs to require that model assumptions, methods and results are electronically documented, publicly available and easily replicated. Even better, we could follow the lead of Texas and invest in models that serve as a standard for determining pumping limits and settling disputes.
California should also clarify groundwater claims. The law authorizes local groundwater agencies to limit individual pumping. Defining and capping pumping rights would increase incentives to invest in groundwater recharge and facilitate trading within basins, a key way to lower the costs of limiting pumping.
The state must account for groundwater use and recharge. The new law has spurred widespread interest in using available surface water to recharge groundwater basins. Establishing transparent estimates of volumes recharged, and crediting land owners who implement such practices, can defray costs.
Across California, local water managers and users are beginning the hard work of bringing their groundwater budgets into balance. The administration and Legislature should bolster this process by establishing accounting standards and supporting their adoption at the local level.
Alvar Escriva-Bou is a research fellow at the Public Policy Institute of California’s Water Policy Center and can be contacted at firstname.lastname@example.org. Ellen Hanak is the center’s director and can be contacted at email@example.com. Jay Lund is director of the Center for Watershed Sciences and professor of civil and environmental engineering at the University of California, Davis, and can be contacted at firstname.lastname@example.org.