Frequently Asked Questions

A map of the Delta’s primary and secondary zones, Suisun Marsh, major roads, and waterways.

Did you know?

  • California’s first National Heritage Area is in the Sacramento-San Joaquin Delta.
  • 27 million Californians rely on the Delta for at least some portion of their water.
  • The Delta Stewardship Council was created to align Delta decision-making with science.
  • More than 750 plant and animal species can be found in the Delta.
  • The Delta supports a $50 billion global agricultural industry.

These facts and more can be found in the frequently asked questions below. Have a question about the Council or the Delta that is not listed? Ask us by emailing

The map of the Delta to the right was produced as part of the Council’s Delta Adapts initiative, which aims to create a climate-resilient future for the Delta. Please click on the map to view it in a larger format.

What is the Delta Stewardship Council?

The Delta Stewardship Council is the California State agency tasked with creating and implementing a comprehensive management plan for the Delta in support of the state’s coequal goals of providing a reliable water supply for California and protecting, restoring, and enhancing the Delta’s ecosystem while protecting the Delta's unique and evolving character.

The Council was created by the 2009 Sacramento-San Joaquin Delta Reform Act to serve as an independent voice for science and policy in the Delta. Its core mission is to further the state’s coequal goals through the implementation of a long-term management plan for the Delta. This includes facilitating, coordinating, and integrating the activities of hundreds of local, state, and federal agencies that have responsibilities directly related to water, ecosystems, and the Delta.

What are the coequal goals?

In the Delta Reform Act, the California Legislature declared the following goals for the Delta:

  1. Achieve the two coequal goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem. The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place.
  2. Protect, maintain, and, where possible, enhance and restore the overall quality of the Delta environment, including, but not limited to, agriculture, wildlife habitat, and recreational activities.
  3. Ensure orderly, balanced conservation and development of Delta land resources.
  4. Improve flood protection by structural and nonstructural means to ensure an increased level of public health and safety.

Who serves on the Delta Stewardship Council?

The Delta Stewardship Council is composed of seven council members who represent different parts of the state and offer diverse expertise in fields such as agriculture, science, the environment, and public service. Of the seven council members, four are appointed by the Governor, one each by the Senate and Assembly, and the seventh is the chair of the Delta Protection Commission. Council members are appointed to four-year terms.

What is the Delta Plan?

Formally adopted in 2013 to meet the requirements of the Delta Reform Act, the Delta Plan is the Council’s comprehensive, long-term management plan for the Delta. It includes policies, recommendations, and a suite of performance measures to further the state’s coequal goals. The Delta Plan is enforceable through regulatory authority in the Delta Reform Act that requires state and local agencies to be consistent with the Delta Plan.

In response to changing circumstances, and in accordance with commitments made in the original plan, the Council has adopted five amendments to the Delta Plan: (1) performance measures, (2) single-year water transfers, (3) conveyance storage and operations, (4) output and outcome performance measures, and (5) the Delta Levees Investment Strategy. These amendments reflect the Council’s adaptive management approach to the implementation of the Delta Plan and respect for the Delta as a living, evolving place.

Information about current Delta Plan amendments that the Council is undertaking can be found here.

How is the Delta Plan implemented?

After its adoption of the Delta Plan in 2013, the Council established the Delta Plan Interagency Implementation Committee (DPIIC) to facilitate Delta Plan implementation strategies and actions across agencies. DPIIC is comprised of leaders from 18 federal and state agencies that have been determined by the Council as vital to the successful implementation of the Delta Plan. Each implementing member agency is represented by the highest level of authority to formally speak on behalf of the agency at a policy and management level.

The Council also engages with state and federal agencies to prioritize funding and actions that support Delta Plan implementation. This includes working directly with project proponents to ensure projects are consistent with the Delta Plans policies, recommendations, and adaptive management approach.

How does the Delta Plan incorporate the best available science?

The Council’s Delta Science Program develops unbiased and relevant scientific information to strengthen science and policy connections across the Delta, Suisun Marsh, and the San Francisco Bay. The Delta Science Program also works to integrate resources across state and federal agencies and to communicate timely information to decision-makers, resource managers, stakeholders, the broader scientific community, and the public.

The ten members of the Delta Independent Science Board (Delta ISB), which report to the Council, provide oversight of the scientific research, monitoring, and assessment programs that support the adaptive management of the Delta. By law, all Delta scientific research, monitoring, and assessment programs must be reviewed at least once every four years. To date, the Delta ISB has completed six programmatic reviews on ecosystem restoration, fish and flows, adaptive management, Delta levees, Delta as a place, and water quality to help inform Council initiatives.

What is the Delta Stewardship Council’s role in projects covered under the Delta Plan, i.e., those that stand to affect the Delta?

The Delta Reform Act granted the Council authority to ensure the consistency of state and local public agency actions within the Delta Plan. Water Code section 85225.30 required the Council to adopt administrative procedures governing appeals, which are exempt from the normal state rulemaking process.

State and local agencies proposing to undertake a project covered by the Delta Plan must prepare and file a “consistency determination” with the Council, meaning they must demonstrate that the project is consistent with requirements in the Delta Plan. Any person may challenge that consistency determination by bringing an appeal to the Council.

The Council, in turn, must hold a public hearing on the appeal and issue written findings, either denying the appeal or remanding the matter to the state or local agency for reconsideration of the proposed project based on the finding that the consistency determination is not supported by substantial evidence in the record before the agency.

To learn more about the consistency determination process or the Council’s decisions related to covered actions visit here.

Is the purview of the Delta Stewardship Council and the Delta Plan limited to the legal boundaries of the Delta?

No, the scope of the Delta Plan encompasses much of California. In order to meet the coequal goals of a reliable water source and a restored ecosystem, coupled with the recognition of the Delta as an evolving place, the California Legislature gave the Council authority over any project or action that stands to affect the Delta. This was done given the amount of water supply that flows through the Delta, its interconnectedness with the majority of the state’s watersheds, and its critical role in state and federal water projects.

How are the Delta Reform Act and the Delta Plan connected, and how do they affect ongoing planning efforts in the Delta?

The Delta Reform Act acknowledges several other ongoing Delta plan processes by name including the Central Valley Flood Protection Plan and the Delta Protection Commission Economic Sustainability Plan. The Act allows the Council to review them and authorizes the Council to incorporate those plans in whole or in part if they meet the statutory criteria of the Delta Plan.

Subsequently, Section 85350 of the Act offers an all-encompassing statement, which stipulates, “The Council may incorporate other completed plans related to the Delta into the Delta Plan to the extent that the other plans promote the coequal goals.”

How does the Delta Stewardship Council differ from previous efforts - such as CALFED - to manage the Delta?

The Council is the successor to the California Bay-Delta Authority and CALFED Bay-Delta Program. California legislators designed the seven-member Council to be small and authoritative, compared to the more than two dozen state and federal agencies that made up CALFED.

The Council oversees Delta activities by consulting with state, federal, and local agencies; ensuring their projects and activities in the Delta comply with the Delta Plan. Moreover, the Delta Plan is legally enforceable.

Where can I learn about what the Delta Stewardship Council’s has been working on?

For highlights of the Council’s work, visit the Annual Reports page. Annual Reports for years prior to 2019 are available upon request via You can also check out the “Latest News” header on the Council’s home page for recent information.

How can I contact and engage with the Delta Stewardship Council?

Email us at or visit here for the Council’s Social Media platforms to get the most up-to-date information.

You can also sign up to receive email updates from the Council.

What is the Delta?

The Sacramento-San Joaquin Delta is formed by the confluence of the state’s two largest rivers: the Sacramento, flowing south from its headwaters near Mount Shasta, and the San Joaquin, flowing north from its origins high in the southern Sierra Nevada. Joining the Sacramento and San Joaquin are the Mokelumne, Cosumnes, and Calaveras rivers. These rivers and their tributaries carry about half of the state’s total annual runoff. Freshwater from the rivers mingles with saltwater from the San Francisco Bay and Pacific Ocean’s tides, forming the largest estuary on the west coast of North America. The Delta and Suisun Marsh include more than 1,100 miles of levees and 140 leveed islands and tracts.

Where is the Delta located?

The Delta spans about 738,000 acres in Northern California, at the western edge of the Central Valley. The legal Delta includes area in Alameda, Contra Costa, Sacramento, San Joaquin, Solano, and Yolo counties. Major cities at least partly within the Delta include Sacramento, West Sacramento, and Stockton. Smaller, legacy cities like Locke, Walnut Grove, and Courtland also help define the Delta region.

Why is the Delta important to California and the region?

The Delta is a regional, state, and national treasure. More than 627,000 people in dozens of communities call the Delta home. It is also home to more than 750 animal and plant species and 55 fish species, many of them threatened or endangered.

Agriculture is a defining feature of the Delta. The majority of land in the Delta is used to grow crops, including alfalfa, almonds, asparagus, corn, processing tomatoes, rice safflower, wheat, winter cereals, and wine grapes. Water from the Delta also supports California’s $50 billion agricultural industry, which includes more than 400 commodities. More than 1,800 agricultural users draw water from the Delta.

The Delta is the hub of state, federal, and local water systems that provide at least a portion of the water supply needs for two-thirds of all Californians, or about 27 million people. Water diversions directly from the Delta include the State Water Project, the federal Central Valley Project, the Contra Costa Canal, the North Bay Aqueduct, the City of Vallejo, and the Western Delta Industry.

The Delta is also a world-class recreational destination, attracting about 12 million visitors per year, who take advantage of its 290 shoreline recreational areas, 300 marinas, 57,000 navigable waterways, and more than 20 species of sport fish.

In 2019, the Delta became California’s first National Heritage Area, a designation granted by Congress to places where natural, cultural, historic, and recreational resources combine to form a distinctive landscape and tell a nationally important story about the country and its experience.

What are the roles of the Delta’s state agencies?

Three state agencies regulate, conserve, and protect the Delta. Read about their missions and how they work together in the “Meet the Delta’s state agencies” information sheet.

What are the major challenges facing the Delta?

Over several decades, the competing demands for the Delta to provide both habitat and water supply have impaired the Delta’s ability to meet either need. The needs of the ecosystem and water users particularly clash during dry years, when there is simply less water to go around.

Many factors continue to threaten the health of the Delta. Agricultural, industrial, and urban runoff pollute its waters. Invasive, non-native species adversely affect the food chain and, as a result, native fish and wildlife populations continue to suffer.

Gradual changes, such as sea-level rise, rising water temperatures due to climate change, and additional invasions of exotic species, are also transforming the current ecosystem in ways that are difficult to anticipate or manage. California’s Fourth Climate Change Assessment indicates higher sea levels, subsidence, and increased flooding are serious threats to Delta levees and increase the risk of levee failure. Rising temperatures and salinity in the Delta threaten native species, ecosystems, and saltwater intrusion in areas from which water is pumped for agricultural and municipal uses threatens critical water supply systems.

One of the well-known issues related to these challenges is the plight of the Delta smelt, a small fish having a big impact on Delta management. In 2007, a California judge protected the endangered Delta smelt by curtailing water export deliveries from the Delta. In July 2016, state and federal agencies released a Delta Smelt Resiliency Strategy aimed at rapidly improving conditions for endangered Delta smelt. This is one of many strategies that represent a management shift for state and federal agencies, which are now working to adaptively manage and systematically address multiple environmental stressors in the Delta.

Where can I learn more about the Delta?

Contact us via or visit here for the Council’s Social Media platforms.

You can also sign up to receive email updates from the Council.