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How California can overcome water wars

California is a semi-desert state where the availability of water determines land use and, in turn, shapes the economy.

This essentially explains why Californians have been fighting over water for the state's entire 174-year history.

The decades of the so-called “water war” may be nearing a climax as climate change, economic development, stagnant population growth and environmental awareness force decisions about California’s water future.

A new study conducted by researchers at three University of California campuses projects that a combination of factors will reduce California's water supplies by as much as 9 million acre-feet per year — roughly the equivalent of all nonagricultural human use. These factors include the impacts of climate change, new regulations to curb overuse of groundwater, reducing Colorado River diversions and increasing environmental pressures, particularly from the Sacramento-San Joaquin Delta.

In an average year, about 200 million acre-feet of water falls on the state as rain or snow. Most of this is consumed by evaporation and infiltration, leaving about 80 million acre-feet for three main uses. Agricultural irrigation and environmental runoff to the sea are roughly equal at about 35 million acre-feet, while residential, commercial and industrial users use the rest.

The latter use is not only the smallest of the three, it has also remained remarkably stable thanks to intensive conservation programs – and has even declined somewhat despite decades of high population growth.

Although water officials continually warn Californians to limit their personal water use, in recent years, particularly during droughts, the dispute between agricultural interests and environmentalists has centered on the amount of water needed to sustain fish and other wildlife.

Environmentalists have pushed state water agencies, particularly the Water Resources Control Board, to force farmers to divert less water from rivers in order to increase water volumes. Agriculture is also under pressure from new restrictions on tapping groundwater through wells. In addition, California's largest agricultural sector in the country has shifted from seasonal crops to nuts, grapes and other permanent, high-value products that require year-round irrigation.

“To address this situation and pursue good policies, serious and organized attention is needed, as well as consistent, long-term policies without complacency or panic,” the UC study concluded.

The new study supports a 2022 Newsom administration strategy paper calling for 4 million acre-feet of new water storage, an additional 1.3 million acre-feet of savings from wastewater conservation and reuse, and new supplies from desalination and other processes.

The study comes at the same time as a bill that would set new goals for improved water supplies (Senate Bill 366) is making its way through the Capitol with broad support from water stakeholders of all kinds.

It's one thing to point out that California is facing a potential water crisis and that serious efforts should be made to prevent its impacts. But actually doing something about it faces two major hurdles: the snail's pace of implementation of water projects of all kinds and the unresolved conflicts over water rights, some of which date back to the state's founding in 1850.

The Sites Reservoir is an example of the former. The project in the western Sacramento Valley, which would create 1.5 million acre-feet of off-stream storage capacity, has moved closer to reality in recent years after being on hold for seven decades. The same is true of the long-planned canal or tunnel that would bypass the Sacramento-San Joaquin Delta.

The idea of ​​a comprehensive, long-term program to make California's uncertain water supply more resilient sounds great, and the clock is ticking. But that assumes that agencies have the legal authority to implement it.

As long as the issue of water rights is not resolved, the much-discussed redistribution of resources – more in favour of the environment and less in favour of agriculture – will come to a standstill.

CalMatters is a public interest journalism project dedicated to explaining how the California Capitol works and why it matters.