Delta Adapts: Creating a Climate Resilient Future

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Cover of the Delta Stewardship Council’s Delta Adapts: Creating a Climate Resilient Future Vulnerability Assessment document.

The Delta Adapts final Vulnerability Assessment is now available. The Vulnerability Assessment evaluates the vulnerability of the Delta and Suisun Marsh to climate impacts through end of century. The final Vulnerability Assessment addresses comments on the public review draft received during the 60-day public comment period that closed on March 16, 2021.

Final Vulnerability Assessment and Supporting Attachments:

For an introduction to Delta Adapts and a summary of the vulnerability assessment, see the Delta Adapts Story Map and watch the YouTube video.

As part of the Delta Adapts initiative, the Council created a custom social vulnerability index to identify areas within the Delta that are socially vulnerable to climate change impacts. For more detail on the factors considered in the index or the identified areas, see the Delta Social Vulnerability Index interactive map. The Council also created a flood explorer map which allows users to select various flood scenarios to visualize areas exposed to flooding, as shown in



California relies on the Sacramento-San Joaquin Delta in many ways. It supplies a portion of the drinking water for 27 million Californians, fuels California’s $3 trillion economy, and is a biodiversity hotspot for more than 750 plant and animal species. It is also home to more than 627,000 people spread across rural agricultural communities, legacy communities, and urban areas including Sacramento, West Sacramento, Stockton, Lathrop, Manteca, and the eastern Bay Area. Changes in climate put the state’s water supply, economy, and biodiversity at risk—decreasing water quality and increasing stress on levees that protect residents, farmland, and the state’s network of public utilities from mass flooding, and the species who thrive in the region’s ecosystems.

As the world continues to feel the pressures of climate change and experience hotter temperatures, regional adaptation rooted in science-based decision-making is more critical than ever. We have to move quickly, and we have to move together to both plan and respond.

View of the Sacramento River from a dry riverbank.

The Delta Stewardship Council decided to take action in the Delta and Suisun Marsh in response to climate change at its May 2018 meeting, directing staff to begin a two-phase effort preparing:

  1. a vulnerability assessment to improve understanding of regional vulnerabilities in order to protect the vital resources the Delta provides to California and beyond with state interests and investments top of mind, followed by
  2. an adaptation plan detailing strategies and tools that state, regional, and local governments can use to help communities, infrastructure, and ecosystems thrive in the face of climate change.

Together, these two phases form the Delta Adapts: Creating a Climate Resilient Future initiative, a comprehensive, regional approach to climate resiliency that cuts across regional boundaries and commits to collaboration across state, local, and regional levels.

Delta Adapts supports:

  • The Delta Reform Act, passed by the California Legislature in 2009, which mandates the consideration of “the future impact of climate change and sea level rise” in restoration planning and identifies a restoration timeline horizon of 2100. The Act also notes that the Delta Plan may address “the effects of climate change and sea level rise on the three state highways that cross the Delta.”
  • Executive Order B-30-15, signed by Governor Brown in April 2015, which requires California state agencies to incorporate climate change into planning and investment decisions. It also requires agencies to prioritize natural infrastructure and actions toward climate preparedness among the most vulnerable populations.
  • The Delta Plan, adopted by the Council in 2013, which serves as California’s roadmap for the region in support of the coequal goals of a reliable statewide water supply and resilient Delta ecosystem. Research on climate change has advanced significantly since the Delta Plan’s adoption, with important implications for the Council as it seeks to fulfill its mission of furthering the coequal goals—which are sure to be continuously impacted by climate change.
A levee filled with water and surrounded by dry land in the Sacramento-San Joaquin Delta.

As an agency of experienced planners, engineers, scientists, and communicators, the Council is uniquely equipped – and authorized – to steward the region toward resiliency. The Council regulates actions to ensure they support statewide water supply reliability and Delta ecosystem resiliency, and has the resources needed to guide climate adaptation in the region. Through its strong working relationships with government agencies on the federal, state, regional, and local levels, the Council has the ability to influence action in the Delta to improve its resilience over time and communicate the statewide implications of anticipated regional impacts.

A screenshot of Harriet Lai Ross beginning a virtual Delta Adapts PowerPoint presentation. The title slide is on display.
Harriet Lai Ross virtually presenting a PowerPoint to the Delta Stewardship Council. Her presentation slide displays information on the 'significance of Delta Adapts.'

The Council’s role in Delta Adapts has three core elements. It is:

  • The convener bringing various partners together to work as part of a broader team,
  • The initiator of the regional planning process, and
  • An active participant collaborating with a robust group of experts and interested stakeholders.

Goals and Process

The goals of Delta Adapts are to:

  • Inform future work at the Council;
  • Provide local governments with a toolkit of information to incorporate into their regulatory and planning documents;
  • Integrate climate change into the state’s prioritization of future Delta actions and investments; and
  • Serve as a framework to be built upon by the Council and others in years to come.

Council staff are pursuing these goals across the two phases, while following the statutory requirements outlined in the Delta Reform Act of 2009. Delta Adapts will consider climate change impacts that are expected to occur and amend the Delta Plan, where applicable.

The first phase is a vulnerability assessment characterizing climate change stressors as well as potential physical hazards posed by these stressors.

Icons representing climate stressors in the Sacramento-San Joaquin Delta. Primary stressors include precipitation and hydrologic patterns, air temperature, sea level rise, and frequency of extreme events. Secondary stressors include wildlife, wind, and fog.

The vulnerability assessment assesses risks posed by these hazards to Delta communities (including vulnerable communities) and a variety of regional assets, including: agriculture, community facilities and services, water management and flood control infrastructure, parks and recreation, transportation, water supply, and ecosystems. The first phase of the Delta Adapts initiative has been completed.

The second phase is development of an adaptation strategy identifying a range of policy and management actions that could be taken, both by the Council and others, that would improve regional resilience to climate change. This adaptation strategy will identify how we can respond to the climate vulnerabilities consistent with the following resilience goals.

  • Promote statewide water conservation, water use efficiency, and sustainable water use (Water Code 85020(d)).
  • Improve water quality to protect human health and the environment consistent with achieving water quality objectives in the Delta (Water Code 85020(e)).
  • Improve the water conveyance system and expand statewide water storage (Water Code 85020(f)).
  • Restore the Delta ecosystem, including its fisheries and wildlife, as the heart of a healthy estuary and wetland ecosystem (Water Code 85020(c)).
  • Restore critical physical and biological processes; connectivity; complexity and diversity; redundancy; at large scales with a long time horizon in mind.
  • Protect and enhance the unique cultural, recreational, and agricultural values of the California Delta as an evolving place (Water Code 85020(b)).
  • Reduce risks to people, property, and state interests in the Delta by effective emergency preparedness, appropriate land uses, and investments in flood protection (Water Code 85020(g)).
  • Increase the resilience of Delta communities, especially those with characteristics that make them more vulnerable to climate risk due to physical (built and environmental), social, political, and/or economic factors. These factors include, but are not limited to, race, class, sexual orientation and identification, national origin, and income inequality (OPR 2018).
  • Prioritize actions that protect the most vulnerable populations (EO B-30-15).
  • Maintain and improve local economic vitality and access to diverse employment opportunities by preserving and growing, where appropriate, key economic and employment drivers and associated infrastructure that support the Delta economy and communities.
  • Promote the development of urban growth strategies that reduce climate risks by focusing new development in more resilient areas, enhancing the Delta ecosystem, and supporting resilient farming and recreation activities.
  • Improve and enhance the resilience of the Delta transportation network while supporting the achievement of regional and statewide greenhouse gas reduction targets.
  • Foster collaboration and build capacity among federal, state, and local agencies, non-governmental and private organizations, and communities in the Delta.
  • Commit to working cooperatively to identify and mitigate climate change impacts and risks.
  • Improve coordination among regulatory agencies to reduce program or legal barriers to addressing current and future flood, drought, wildfire, and other risks that will be exacerbated by climate change.
  • Incorporate climate change into state and local Delta planning and investment decisions (EO B-30-15).
  • Prioritize actions that incorporate natural and green infrastructure solutions (EO B-30-15).
  • Define the Council’s role in coordinating adaptation responses in the Delta.
Aerial view of aquatic plant invaded water near a levee road in the Sacramento-San Joaquin Delta.

Relative costs of implementation and prioritization of actions will also be included in the development of the adaptation strategy.

While the Council is leading these two phases, both phases are being developed in partnership with technical experts, state and local governments, and community representatives to ensure the use of best available science, to allow for broad engagement in the planning of the initiative, and to reflect the broad range of stakeholder interests in the Delta. To promote the exchange of information between these groups, Council staff established a Stakeholder Work Group (SWG). In addition to the SWG, a Technical Advisory Committee (TAC) provides expert knowledge, review, and guidance throughout the development of Delta Adapts. The TAC includes the following experts from public agencies, academic institutions, non-profit organizations, the private sector, and individuals with particular knowledge of climate change, the Delta, and its resources.

  • John Andrew and Lindsay Correa, California Department of Water Resources Climate Change Program
  • Dana Brechwald, San Francisco Bay Conservation and Development Commission
  • Casey Brown, University of Massachusetts Hydrosystems Research Group
  • Dan Cayan, Scripps Institute of Oceanography
  • Gilbert Cosio, MBK Engineers
  • Steve Deverel, Hydrofocus
  • Virginia Gardiner, Delta Protection Commission
  • Michael George, State Water Resources Control Board Delta Watermaster
  • Ted Grantham, UC Berkeley Natural Resources Conservation
  • John Herman, UC Davis School of Engineering
  • Michael Kent, Contra Costa Health Services Hazardous Materials Commission
  • Nuin-Tara Key, Governor’s Office of Planning and Research
  • Noah Knowles, United States Geological Survey
  • Josue Medellin-Azuara, UC Merced
  • Brett Milligan, UC Davis Department of Human Ecology
  • Stuart Siegel, San Francisco State University
  • Brian Vaughn, Yolo County Health & Human Services Agency
  • Sam Veloz, Point Blue

Additional Materials


To learn more about Delta Adapts, its SWG, or other ways to engage in our process, contact

A microphone resting in a stand.