Document Type


Journal/Book Title/Conference

California WaterBlog


Public Policy Institute of California

Publication Date



water storage, freshwater ecosystem health, drought, State Water Project, Central Valley Project

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Last Page



Storing water in reservoirs is important for maintaining freshwater ecosystem health and protecting native species. Stored water also is essential for adapting to the changing climate, especially warming and drought intensification. Yet, reservoir operators often treat environmental objectives as a constraint, rather than as a priority akin to water deliveries for cities and farms. Reservoir management becomes especially challenging during severe droughts when surface water supplies are scarce, and urban and agricultural demands conflict with water supplies needed to maintain healthy waterways and wetlands. In times of drought, most freshwater ecosystems suffer.

This blog post examines 2021 water year actions by the federal Central Valley Project (CVP) and the State Water Project (SWP), which sought to maximize water deliveries while meeting environmental regulatory standards in a severe drought. Based on this experience, we offer recommendations to better protect the environment if California is faced with dry conditions in 2022 or beyond.


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