The Need for Sites Reservoir

California continues to face severe water challenges: limited supplies and a growing population, compounded by climate change, persistent drought conditions, and increased flow requirements for native fish. Now more than ever, California’s water system needs a more flexible, environmentally friendly solution to capturing and storing water for use when it’s needed most.

Sites Reservoir is an innovative project and a 21st century solution to California’s water crisis. It is different than any other storage project.

Sites Reservoir provides previously unachievable flexibility to the state’s water system without impacting sensitive river channels and critical environmental flows that support endangered fish populations.

Sites Reservoir Works: It achieves California’s co-equal goals of water supply reliability and ecosystem improvement.

Sites Reservoir has been studied for more than 30 years, and has statewide support. It is designed to give water agencies across the state more flexibility to meet both customer demands and environmental needs, especially in dry and critical years. Increased water supplies to farms and cities across California will have an enormous economic impact.

Sites Reservoir

Hands in Water icon

Adding 500,000 acre-feet to California’s water system – enough to serve 3.7 million people for one year.

Group of People icon

Protecting thousands of regional and statewide jobs.

Water Flowing Icon

Up to half of Sites Reservoir’ annual water supplies can be dedicated to environmental flows.

The benefits of Sites Reservoir would outweigh the costs by a wide margin.

The benefits of the Sites Reservoir are expected to exceed costs by $61 million to $72 million annually, by leveraging support and financing of local and statewide water agencies that have already demonstrated significant commitment to the project.

Sites Reservoir Benefits

  • Water Faucit with Drop icon Reliable water for California homes, businesses and farms
  • Fish icon Environmental flows for native fish
  • Drop of water icon Improved water quality
  • Water Cycle icon Contribute to California's renewable energy goals
  • Ground water icon Groundwater recharge
  • House flooding icon Flood management
  • Bird in water habitat icon Pacific Flyway habitat for migratory birds and other native species
  • Recreational Kayak in water icon Recreational opportunities

The Sites Reservoir Region

The Sites Reservoir would be situated on the west side of the Sacramento Valley, approximately 10 miles west of the rural town of Maxwell, in historic Colusa County. The Sacramento Valley is a unique region, known for it’s farming community, rich agricultural benefits, and natural beauty. The region has been considered ideal for off-stream water storage since the 1980’s, a proposal that is widely supported by local community leaders, residents, as well as state water managers and agencies from the Bay Area to Southern California.


Recent News

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Sites Reservoir Needed for Reliable Water Future

Aug. 01, 2019

A flexible, reliable water supply is essential to California’s economy and to the job creation and job security goals of…

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Sites Reservoir – Improved Resilience for California in Wet, Dry and Average Years

Aug. 01, 2019

As California seeks water resiliency and solutions to prepare for more extreme wet and dry years, Sites Reservoir emerges as…

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California Needs to Build Sites Reservoir. Here’s Why.

Jul. 07, 2019

California’s aging water infrastructure desperately needs an upgrade. Shorter, more intense rain storms, less snowpack and more prolonged stretches of…

Water 101

The water that Californians use for drinking, recreating and protecting the environment moves through a system that is arguably the most complex in the world.

PDF Document of Water Planning

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Not only is there a maze of rivers and aquifers and channels and pipes and dams and tunnels…there is also an intricate system of laws and regulations that local, state and federal agencies deploy to protect and preserve this life-sustaining natural resource.

A complicating factor is that California is by-and-large an arid state. Much of our water comes in the form of snowmelt that originates high in the mountains of the Sierra Nevada and Shasta Cascade regions. But the highest demand for water is in the Bay Area and Southern California. Add climate change into the equation—meaning a shift from a snow-supplied system to a rainfall-capture system—and the careful balance becomes more tenuous.

California has two primary sources of water: surface water from rivers, lakes and streams; and groundwater from underground aquifers. There are others sources, including desalination and recycled water, which provide small amounts of water supply locally.

Groundwater has been managed on a local level historically. Implementation of the Sustainable Groundwater Management Act will bring cohesion and data to the groundwater system to help ensure long-term sustainability.

The state’s primary surface water system is comprised of the State Water Project and the federal Central Valley Project. Surface water is captured and stored in reservoirs and later released to meet water supply, flood control, water quality and environmental needs.

California’s primary source of water comes from the Sierra Nevada Mountains in the form of spring runoff, and is delivered through a complicated system of rivers, canals, and dams that work in conjunction to supply the state’s cities, towns, and farms. Our water system is an engineering feat that has fed a growing and thriving economy. But, climate change has resulted in conditions that our current system is incapable of handling – less snow, shorter, more intense storms, and increased salinity due to sea level rise.

Sites Reservoir will help the state adapt to climate change by capturing and storing runoff supplies for use in dry and critical years. Between October 2015 and April 2016, over 1,000,000 acre-feet could have been diverted to Sites Reservoir, filling 60% of its capacity in one year alone.

The project will also help recovering ecosystems by providing up to half of its annual water supplies to environmental flows, which will improve water quality for endangered fish, reduce salinity levels in the Sacramento-San Joaquin Delta (Delta), and improve Pacific Flyway habitat for migratory birds and other native species.

Sites Reservoir would relieve stress on the state’s water system, allowing other reservoirs to hold more water later into the summer months. The added flexibility Sites Reservoir offers would effectively increase the total storage in Northern California by about more than 500,000 acre-feet of water.

By creating a new source of water, and more flexibility in the system, Sites Reservoir has the potential to help California succeed at implementing 21st century water solutions—to meet human AND environmental needs.

  • Groundwater sustainability requires effective groundwater recharge. Sites Reservoir can help store and then move water where and when it’s needed for recharge projects.
  • Salmon need cold water to survive in the late summer and fall. If water for ag and Delta water quality came from Sites Reservoir, cold water pools in Shasta and Oroville could be preserved.
  • If Sites Reservoir had been in place in 2016, about 500,000 acre-feet could have been captured and stored—a much-needed boost to overall state water supplies in the middle of our historic drought.
  • Climate change is creating a new normal: less snow-pack and flashier rainfall. Sites Reservoir is ideally located to maximize the capture and storage of rain.


  • "But if done right, something like the proposed Sites Reservoir in Colusa County – which would be nearly twice the size of Folsom Lake and has bipartisan backing – could be a valuable place to park a downpour."

    Editorial Board

  • "[Sites Reservoir] would deliver benefits statewide by increasing water supply and, with proper management, providing versatility in water delivery for farms, cities and much-needed groundwater recharge. One of the most promising aspects of Sites Reservoir is that a bloc of water would be allocated to the environment."

    Editorial Board

  • "This bi-partisan effort promoting progressive water management is a step forward for California. The dry years in California have shown the importance of surface storage for all beneficial purposes--water needed for cities and rural communities, farms, fish, birds and recreation. An off-stream regulating reservoir on the west-side of the Sacramento Valley (Sites Reservoir) is critical for all these beneficial purposes in the Sacramento Valley, as well as providing statewide water system operational improvements."

    David Guy David Guy
    President, Northern California Water Association

  • "Building Sites Reservoir is vital the Sacramento Valley. We need additional surface water storage to help all aspects of our region for future generations, including four annual salmon runs, habitat for millions of birds that depend on area rice fields, our small towns and family farms."

    Tim Johnson Tim Johnson
    President & CEO, California Rice Commission

  • "Sites Reservoir is a critical project for both the local and statewide economy. A project of this magnitude will help stabilize water supplies and provide much needed economic development in the North State region while also creating thousands of jobs and apprenticeship opportunities for local young men and women."

    Robbie Hunter Robbie Hunter
    President, State Building and Construction Trades Council of California

  • "Sites Reservoir is an incredibly important project for the State of California that meets many of the public benefits required by the Water Bond."

    Assemblyman Gallagher Assemblyman Gallagher

  • "The fact that Sites Reservoir would not dam a river makes it more palatable to many than proposals to raise Shasta Dam on the upper Sacramento River and construct a new dam and reservoir on the San Joaquin River just upstream of the existing Friant Dam and Millerton Lake near Fresno."

    Los Angeles Times Los Angeles Times

  • "Sites Reservoir offers a remarkable opportunity to reoperate California's longest and largest river, the Sacramento, to provide multiple benefits for fish, farms and cities in an innovative manner. By partnering with the Sites Reservoir Authority in the development of the Reservoir, the state would acquire water storage capacity and have management control over the resulting releases to ensure environmental benefits are achieved."

    Senator Feinstein Senator Feinstein

  • "Sites Reservoir is one of the most useful, cost-effective water infrastructure projects California could build. It is an ideal project that can provide water for agriculture, urban uses and the environment. The support for the Sites Reservoir from a majority of the California Congressional delegation speaks to the statewide benefits of the project."

    Congressman Garamendi Congressman Garamendi

  • "North and South, rural and urban, Republican and Democrat, California's leaders agree on one thing: our state needs to invest in Sites Reservoir to meet the water supply challenges of today and the future. Sites provides more water per dollar invested than any other proposed project in the state, enough to supply millions of Californians for an entire year, while also creating environmental benefits and allowing smart recapture and reuse of water released from other reservoirs. Investing in Sites will fulfill the will of the 67% of Californians who supported Proposition 1 funding for water storage infrastructure, and I hope the California Water Commission recognizes the project's diverse benefits."

    Congressman LaMalfa Congressman LaMalfa

  • "As water and environmental managers have been forced to operate under a constant regulatory threat, Sites Reservoir will provide a critical tool for them to solve California's toughest water problems collaboratively and productively."

    Senator Nielsen Senator Nielsen

  • "Building Sites Reservoir is an imperative part of the solution to help California meet our water supply challenges of today and the future. The operational flexibility provided by the unique project offers reliable long-term assistance to California's complex water system."

    Assemblyman Dahle Assemblyman Dahle

  • "But the first part is building Sites Reservoir so there's water available to flush out the delta and augment supplies when water is short. Give the water system some flexibility. Look at all that water flowing down the river and get it [Sites] done."

    Chico Enterprise-Record Chico Enterprise-Record
    Editorial Board
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  • "But the need for it [Sites Reservoir] has only become more urgent as a growing population puts more pressure on perennial water shortages."

    Redding Record Searchlight Redding Record Searchlight
    Editorial Board
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  • "An innovative, off-stream water storage proposal northeast of Sacramento should be one of the top priorities for the state's spending of Proposition 1 water-bond money."

    Los Angeles Daily News Los Angeles Daily News
    Editorial Board
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  • "Sites Reservoir, by comparison, is in the right spot to provide water to help the delta when it's needed. It's also in the right spot to allow more cold water to be saved in Shasta Lake to help endangered and threatened fish populations in the Sacramento River."

    East Bay Times East Bay Times
    Editorial Board
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