The Yuba River and the Bay Delta: A Vital Connection for Salmon and our Communities

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The Yuba River and the Bay Delta are connected by more than water. They are also linked by the migration of salmon, which depend on both habitats for their survival. These fish provide food, recreation, and cultural value for millions of Californians. The water that is crucial to these ecosystems also grows the food we eat and powers our homes. Balancing the demands on California’s limited water supply is a complex challenge. 

What is the Bay Delta? 

The Bay Delta is a large natural estuary that consists of two water systems: the San Francisco Bay and the Sacramento-San Joaquin River Delta. Two major rivers in California, the Sacramento and the San Joaquin, meet and merge at the Delta. That freshwater flows into the Delta, eventually mixes with the salt water in the Bay, and then moves into the Pacific Ocean. Juvenile salmon from the Yuba River make an approximately 110-mile journey through the Bay Delta to the ocean every year. Returning adults hold in the Delta waiting for the right moment before making the 110-mile return journey to spawn in the Yuba. 

Bay Delta

Why is the Bay Delta in peril?  

The Bay-Delta ecosystem is suffering from a shortage of freshwater. This has degraded the natural habitat of many species and the quality of life of Delta communities. The freshwater from the Sacramento and San Joaquin Rivers is diverted at the Delta and exported into two large water storage and delivery systems: the federal Central Valley Project and California’s State Water Project. Numerous dams throughout the Sierra Nevada store water in the winter to water crops and generate power during the summer. They also alter the timing and amount of water that reaches the Delta. Together, all these diversions mean a noticeable reduction in the amount of freshwater that reaches the Delta and the Bay, endangering the survival of many fish and wildlife species — including the spring-run Chinook salmon — and limiting the fresh water available for Delta communities. Between 1980 and 2021, in wet years about 50% of available water flowed through the Delta. In dry years less than 10% of the water may make it.  

Why is the Delta critical for the Yuba River and salmon? 

The Yuba River contributes to the water quality, quantity, and timing of the flows in the Sacramento River and the Bay Delta. Water travels from the Yuba into the Feather and then into the Sacramento. Fresh water flowing through the estuary keeps the Bay-Delta ecosystem thriving. Flows and temperature in the lower Yuba River are critical for juvenile salmon growth while they are in the Yuba. Flows and temperature also contribute to a salmon’s successful journey out to the Delta.  

The first pulses of runoff from winter storms trigger the downstream migratory journeys of juvenile salmon and cue fish that live in the Delta and the ocean that it is time to begin the move to spawning areas in the river.  It is these interconnected freshwater flows, temperatures, and transition zones between the salty ocean and fresh river water that salmon depend on for the timing of their life history events. 

What is the Bay Delta Plan? 

California’s State Water Resources Control Board has been in charge of the water quality and beneficial uses of the Delta since 1978. The Bay Delta Plan has both river flow and water quality requirements to ensure the Bay Delta’s beneficial uses are protected. The Board is now considering updates to that plan. A key reason for the current update is the population decline of native fish species due to a lack of river flows, habitat loss, and poor water quality. These updates focus on flows from the Sacramento River and its tributaries, including the Yuba. The Plan is supposed to be updated every three years, but the current update has now taken over 13 years. The Board needs to act now and restore the Delta and protect salmon. 

What does the Bay Delta need? 

A primary stressor on declining native fish populations is the lack of river flows. According to the best available science, much more of the natural flow of the contributing rivers should be allowed to reach the Bay-Delta without being diverted or stored upstream. An increase in the amount of unimpaired flow is critical to ensuring that the Bay-Delta has enough water to support its many beneficial uses including: environmental health, drinking water, local agriculture, cultural and tribal values, and recreation. The best thing for the health of the Bay-Delta is if 75% of the natural flow makes it through the Delta to the Bay1. This would restore variability in river flow within and between years which is critically important to maintaining natural functions and sustaining native species, including salmon.  

What are the “Voluntary Agreements”? 

The Voluntary Agreements are a process through which the water agencies who manage the rivers that flow to the Bay Delta work with the State Water Board to come up with a plan to balance the needs of the environment with other human demands on water. In 2010, state and federal agencies began meeting with local water agencies to see if they could negotiate voluntary agreements to restore flows and habitats to help restore the Delta. Those discussions have produced a set of proposals that are being considered as one possible alternative in this update to the Bay Delta plan. The Yuba would contribute 33% – 66% of the natural flow in the Spring, depending on water availability and the regulatory constraints of the Yuba River Development Project2.  

The Yuba River can’t protect the Delta alone, though. Across the state, conservation organizations, tribes, and Delta communities are concerned that these agreements do not adequately prioritize the health of the environment, are unenforceable, and actually do little to help the health of the Bay-Delta. The bottom line is that from what we know of these agreements, they provide very little additional water in dry years and none in critically dry years. That lack of water in the most critical water-year types will only exacerbate the decline of salmon populations. We need stronger solutions than the Voluntary Agreements, especially in the face of climate change. 

How does the Bay Delta Plan impact and include Tribal communities? 

The Sacramento San Joaquin river systems and Delta have sustained Indigenous People for over 5,000 years. Many of our landscapes were once managed to support wildlife, plants, and fish sustainably. California tribes’ traditional lands once surrounded the waterways where salmon live and travel.  The loss of salmon has had extreme health and cultural impacts on California’s native people, whose water rights were taken away by colonization.  The Plan needs to both quantify and recognize these Tribal Water Rights.  The Plan also needs to recognize and ensure the protection of Tribal Beneficial Uses (TBUs) such as tribal subsistence fishing and tribal traditions and culture.  

What is the current Plan and Staff Report lacking? 

The current Preferred Alternative is to provide an average of 55% unimpaired flows for the Sacramento River, ranging between 45-65% depending on water-year type. This would be met through contributions from all the major tributaries to the Sacramento River with each tributary contributing different amounts of water depending on sub-basin conditions. The mechanisms through which any of the proposed alternatives would be implemented and enforced are still unclear, although the State Water Board does state that flows in the Agreement would be enforceable. To meet the unimpaired flow objectives, a coordinated water release from reservoirs would be made in the Spring above what is normally released. Some of that water would be made available for human use (e.g. agriculture in the San Joaquin, drinking water in San Francisco). One option is that the additional water would be purchased by the state to maintain those necessary environmental flows.

What is the timeline for decisions? 

Comments are due on the Updated Draft Staff Report on January 19, 2024. The Board is anticipated to release specific changes to the Plan in mid-2024. Public comment and hearings will be held on those changes in mid-2024.  The Final Updates and the Final Staff Report will be considered by the Board in late 2024.   

What can I do? 

Attend a hearing:

December 1st, 9:30 am; or December 11th, 12:00 pm at the Cal EPA Building, 1001 I Street, Sacramento or attend on Zoom.  Sign up here: 

Hearing on Draft Staff Report in Support of Sacramento/Delta Updates to Bay Delta Plan (office.com) 

Write a letter:  

Your comment to the Board is due on January 19, 2024. 

Email: SacDeltaComments@waterboards.ca.gov with the subject:  “Comment Letter – Sacramento/Delta Draft Staff Report.”  

Mail: State Water Resources Control Board Division of Water Rights Attn: BayDelta & Hearings Branch P.O. Box 100, Sacramento, CA 958122000 

For more information: See the State Water Resources Control Board page: 

Bay-Delta Watershed Comp Review | California State Water Resources Control Board 

See also the Boards updated comment period notice for the Draft Staff Report here: 

Revised NOA/Public Comment/Hearing/Workshop for Staff Report on Bay-Delta Updates (ca.gov) 

For further information, please contact: Traci Sheehan, Policy Manager, South Yuba River Citizens League (SYRCL) at traci@yubariver.org 

  1. Framework for Sacramento/Delta Update. Table 1. July 2018. ↩︎
  2. Draft Strategic Plan for the Proposed Agreements to Support Healthy Rivers and Landscapes. Appendix G1 ↩︎
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