In summary

While water delivery curtailments are necessary in a drought year to keep rivers from going dry, they don’t provide protections for nature. We must set aside enough water to support the salmon and other aquatic life.

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By Sandi Matsumoto

Sandi Matsumoto is director of The Nature Conservancy’s California Water Program,

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Julie Zimmerman, Special to CalMatters

Julie Zimmerman is the lead freshwater scientist at The Nature Conservancy in California,

Amid extreme drought, Gov. Gavin Newsom is asking for statewide conservation of 15%, farmers are facing cutbacks in water deliveries, and a mass die-off of salmon is expected. Drought affects us all, so our response must improve the natural systems that make our water, air and food — our existence — possible.

The State Water Resources Control Board has taken the rare drastic step of adopting emergency regulations to curtail diversions of water rights holders when water is not available. The headlines focus on the farmers who are likely to be cut off from surface water supplies, but that isn’t the whole story.

Curtailments are necessary in a year like this to protect more senior water rights holders — and water needed for human health and safety — from unauthorized diversions when there’s not enough water to go around. These curtailments are designed to keep rivers from going dry and water from getting too salty for human use.

What the curtailments don’t do is provide additional protections for nature. In California’s historical system of “first in time, first in right” water rights, the environment comes last.

Instream flow protections exist to protect water quality and, in theory, to prevent the extinction of endangered species, such as Sacramento and San Joaquin river salmon runs. Mandated flows have not been sufficient, however, to enable species, including salmon, to change their trajectory toward extinction.

In almost all years, river flows are insufficient to protect fish and wildlife, but are dire in drought years as human use is prioritized. Even with the curtailments, planned releases this year from Shasta Dam will result in river temperatures being too warm and losses of up to 88% of this year’s winter-run chinook salmon — and the state Department of Fish and Wildlife predicts it will be closer to 100%

Migratory birds will see their Central Valley wetland habitats shrink dramatically, as less water is available for bird refuges and surrogate habitat on flooded farmland, forcing too many birds into small spaces and increasing the likelihood of severe disease spread. The unintended consequences are vast and their impact on humans and nature unknown.

Our water system is overallocated: We are not prepared for this drought or the predicted increased frequency of extreme temperature events under a changing climate.

A resilient system would have water use more in line with availability across all years, so effects on people and nature are less severe and our rivers can support healthy ecosystems, communities and agriculture.

We support the board’s efforts to curtail water use in overallocated rivers to protect water users and help protect public trust values. In the weeks and months ahead, we should be thinking about how we adapt to a changing climate and ensure that our rivers and freshwater species are not an afterthought.

We need to provide enough water for the environment in all years — including drought years — to protect freshwater ecosystems and allow species to recover from the brink of extinction. Water set aside for nature and the ecosystems we rely on must be of sufficient volume and mimic natural patterns of river flow to support ecosystem function. These water set-asides can be flexibly managed, measured as a percentage of unimpaired flow and implemented as “functional flows,” that is, maintaining sediment movement, water quality and environmental cues for fish migration and reproduction. 

In short, allocations of water for the environment must be prioritized in the same way as the most senior water rights and protected accordingly.

Already-occurring climate change effects are harming freshwater systems and ecological values faster than we can reconcile. Investments are needed to improve monitoring, drought planning and flexible management strategies that ensure water is available when and where it is needed for nature.

In this era of weather extremes, water management should treat rivers not as water conveyance, simply  to be extracted and destroyed, but as resources that when sustained support the cities, farms, freshwater quality, critical ecosystems and unique treasures that define California. 

Under current use rules, one-half of the plants and animals that are dependent on freshwater could go extinct in this century. This future is closer than you think — but we can still act now to ensure water is managed more sustainably. 


Sandi Matsumoto has previously written about groundwater management.

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