The draft plan estimates costs for levee improvements and ecosystem restoration in the Delta through 2050 range from $5.7 to $8.5 billion
The Delta Stewardship Council recently released the draft Delta Adapts Adaptation Plan, marking a significant step forward in addressing the impacts of climate change on the Delta and Suisun Marsh. This comprehensive plan is now open for public comment through January 17, offering an opportunity for stakeholders, experts, and community members to contribute to shaping the future of the region.
Recognizing the urgency of the climate crisis, the draft Delta Adapts Adaptation Plan highlights the need to prioritize resilience in the face of anticipated climate impacts and provides an actionable framework to drive much-needed climate adaptation efforts across the region. It proposes a wide range of climate adaptation strategies tailored specifically to the Delta and Suisun Marsh. It identifies lead and partner agencies responsible for implementing these strategies, examines potential tradeoffs inherent in various adaptation actions, and draws on illustrative case studies to demonstrate how these proposals could unfold in practice. This is the first climate adaptation plan for the Delta that takes an integrated approach, addressing multiple sectors and issues with a unified vision for a sustainable future.
“The work is being led by the Council, which was created to help safeguard Delta assets and climate adaptation is a critical consideration to achieving our agency’s mission,” said Jeff Henderson, Deputy Executive Officer for Planning & Performance at the November meeting of the Delta Stewardship Council. “We’ve identified needs for partnerships and leaders in this Plan, as much of the Plan will be accomplished by others. The Council’s role is to coordinate and lead; the implementation is shared with other partners.”
Delta Adapts consists of two phases: A vulnerability assessment (VA) to improve understanding of regional vulnerabilities due to climate change to protect the vital resources in the Delta, and an Adaptation Plan detailing strategies and actions to adapt and respond to those vulnerabilities.
Phase One: Vulnerability assessment
Phase One began in 2018 with a vulnerability assessment in which assets and systems most at risk from climate change were identified. The Council approved the Delta Adapts vulnerability assessment in June 2021.
The findings of the Delta Vulnerability Assessment:
- Flood risk is one of the most pressing threats to the Delta, and it will worsen in the future with changes in sea levels, more variable precipitation, hydrology, and temperatures.
- These impacts will not impact all Delta residents equally.
- Due to climate change, Delta water exports will be less reliable.
- The existing water supply system doesn’t have enough storage to capture anticipated increases in runoff due to more variable precipitation.
- In-Delta water uses may be threatened by episodic water quality declines, with future droughts potentially exposing more acres of Delta agriculture to saltier water than has historically occurred.
- Agricultural production will shift due to climate change.
- The number of extreme heat days will increase Delta-wide.
Phase two: Adaptation plan
Phase two expands on the vulnerability assessment by outlining strategies and actions to adapt to and address those vulnerabilities.
The Plan was developed with input from a diverse array of individuals, organizations, and agencies to inform the planning process. The outreach included a stakeholder workgroup with four technical focus groups, meetings and interviews with farmers and landowners, presenting at community meetings and events, and targeted outreach meetings with agencies, community-based organizations, and other Delta interests.
“This initiative really has been a vehicle for some of our most far-reaching engagement that I think we’ve done to date by Council staff and has also been the foundation for many new and revived relationships throughout the region,” said Morgan Chow, Environmental Program Manager in the Climate Change and Environmental Justice Unit. “We haven’t just reached new audiences, but we’ve also reached folks in new ways. And we are continuing to do outreach throughout the public comment period and tribal consultation period.”
Adaptation strategies
Council staff developed adaptation strategies for State, tribal, and local decisionmakers and land managers to reduce climate vulnerabilities for Delta communities, infrastructure, and ecosystems. The strategies are informed by the “One Delta, One Science” approach to strengthen coordination between scientists, agencies, and affected parties, and make decisions using the best available science.
The Plan has four areas of focus: agriculture, flood risk reduction, ecosystem, and water supply reliability, with equity integrated throughout. The bulk of the Plan includes strategies and implementing actions which are either physical and or management-level actions for the focus areas and will be realized differently depending on the region in the Delta.
The tribal and environmental justice work significantly informed the equity components of the Delta Adapts report, and the proposed adaptation actions address the distributive justice issues related to flood risk, water supply, water quality, water affordability, pollution burden, recreation and outdoor access, food security, housing, and others.
“Our strategies in this plan really call out the need for representation in project decisions and planning, the need to invest in areas that have social vulnerability to climate impacts, and the need to communicate the vulnerability and risk in new and more effective ways to the communities that are vulnerable,” said Ms. Chow.
The cost of adaptation
A critical aspect of planning for climate adaptation is understanding the associated costs. It is inherently more expensive to recover assets and communities after they are impacted by climate hazards than to address adaptation needs proactively.
The Plan assesses the potential costs of implementing necessary levee improvements and ecosystem restoration efforts across the Delta through 2050. Levee improvements focus on raising the top of the levee to accommodate anticipated increases in water levels due to sea level rise and changes in watershed hydrology. For ecosystem restoration, cost estimates include planning, design, permitting, and construction, as well as a range of restored acreage needed to achieve Delta Plan targets of 60,000 to 80,000 acres.
The total estimated costs for levee improvements and ecosystem restoration through 2050 range from $5.7 billion to $8.5 billion. The variation in cost is primarily driven by the amount of acreage targeted for restoration.
This level of funding presents a significant challenge and highlights the importance of identifying sustainable funding sources. The Plan outlines the need to prioritize investments and explore additional revenue options to support the implementation of adaptation strategies. Taking these necessary steps will ensure the Delta region is better prepared to address future climate vulnerabilities.
North Delta
The North Delta consists of rural, agricultural, and many legacy communities. Water quality is a concern as there are high levels of organic carbon and pollutants, which can be exacerbated by low flows. Strategies here focus on water storage, infrastructure, reservoir operations, and water quality.
The North Delta has a lower flood risk than the other parts of the Delta but still has vulnerabilities, so flood risk strategies include time sensors and early warning systems.
North Delta agriculture is well suited for integrated farming systems, as it is relatively isolated from certain extreme weather events. So strategies that are important here are around climate-smart agriculture. The North Delta ecosystem has more water and pasture, which supports birds, and a higher ecological adaptation potential for intertidal and upland migration space. So relevant strategies include prioritizing multi-benefit project options and considering impacts to agriculture.
Central Delta
The Central Delta is the largest region in the Delta and home to many legacy communities, some with high social vulnerability. The flood risk is high due to land subsidence and the levees are at high risk of overtopping and failure without regular maintenance; the costs to improve levees are the highest. Strategies revolve around drainage systems, active pumps, and flood gates to reduce risk, as well as subsidence halting and reversal strategies.
Water supply strategies in the central Delta must be integrated with flood risk reduction strategies, as flooding can impact water quality and supply. Subsidence poses challenges to the central Delta, and exposed peat contributes to greenhouse gas emissions. So, the strategies are related to halting and reversing subsidence and considering economics.
South Delta
The State Water Project and Central Valley Project pumps are located in the South Delta, which is critical to maintaining water supply across the state. This region has the highest flood risk in the Delta, and there is the added impact of reduced channel capacity due to sedimentation and aquatic invasive plants. So relevant strategies focus on fortifying and improving the levees, real-time monitoring, and incorporating nature-based solutions.
For agriculture, salinity and invasive species pose the most significant challenges. The South Delta has less readily available land for large-scale restoration. However, there are opportunities for public-private partnerships, such as Paradise Cut.
Suisun Marsh
This area primarily consists of managed wetlands and is a transition zone from the fresh riverine to saltwater; hunting and wildlife are a large part of the economy and culture. Sea level rise is a predominant driver for flood risk, so restoring tidal wetlands is one way to help buffer the impacts.
The marsh is designated as an important bird area of global importance, so the strategies focus on maintaining habitat while balancing the other needs of the marsh.
Out of Delta
Ms. Chow noted that the Plan includes strategies for areas outside of the Delta, which acknowledges that activities upstream and beyond the Delta directly impact the Delta and the marsh.
How the Plan will be used
The Plan is intended to be used in three ways:
- To align agency, community, tribal, and other adaptation practitioner’s priorities;
- To act as a framework and guidance document for future adaptation in the Delta; and
- To highlight the need for investment in the Delta for climate adaptation projects as well as research and data needs.
Council staff will use the Plan to convene agencies and organizations around priorities, promote more representative decision making in Delta governance, direct resources to support those that need them the most, share the findings across the region, and improve risk communication.
How to submit your comments
Comments are being accepted on the draft Delta Adapts adaptation plan through January 17. Comments can be submitted to climatechange@deltacouncil.ca.gov or by mail to:
Delta Stewardship Council
ATTN: Morgan Chow
715 P Street, 15-300
Sacramento, CA 95814
You can also join a hybrid discussion on January 6 from 4pm to 6pm; comments and ideas heard at this hybrid discussion will be considered along with comments submitted via email or mail. Attend in person at the Natural Resources Building, 715 P Street, Sacramento, CA, room 221C; or participate virtually on Zoom. For planning purposes, all encourage attendees (in-person and virtual) to register for the event and answer the optional questions on Zoom here.
