Delta Adapts: Creating a Climate Resilient Future Sacramento-San Joaquin Delta Climate Change Adaptation Plan (Draft)

Delta Stewardship Council (Delta Council) | November 1st, 2024

Initiated in 2018 by the Council, Delta Adapts began with a Climate Change Vulnerability Assessment (CCVA) to understand how regional climate impacts will affect the Delt

Initiated in 2018 by the Council, Delta Adapts began with a Climate Change Vulnerability Assessment (CCVA) to understand how regional climate impacts will affect the Delta’s ecosystems, water supply, infrastructure, agriculture, and communities, including socially vulnerable communities (defined in Chapter 1). Now, this Adaptation Plan builds upon the CCVA and proposes strategies to address how Delta communities, infrastructure, and ecosystems can adapt to climate change in a manner consistent with the Council’s resilience goals.

Delta Conveyance Project: Modernizing California’s Water Infrastructure, Fast Facts 2024

California Department of Water Resources (DWR) | September 13th, 2023

Delta Levee Investment Strategy: Risk Analysis Methodology

Delta Stewardship Council (Delta Council) | July 20th, 2016

Levees in California’s Sacramento-San Joaquin Delta (Delta) reduce flood risk to people, property, natural resources, and infrastructure systems of statewide importance

Levees in California’s Sacramento-San Joaquin Delta (Delta) reduce flood risk to people, property, natural resources, and infrastructure systems of statewide importance. Levee failure (such as a levee breach) could cause devastating flooding, potentially resulting in injury or loss of life, damage to property and infrastructure, disruption of water supply, and harm to environmental resources of statewide significance. Currently, the State of California (State) does not have a long-term strategy to guide future investments of its limited funding for Delta levees. The 2009 Delta Reform Act directed the Delta Stewardship Council (Council) to lead the effort to develop and recommend priorities for State investments in Delta levees to reduce flood risks and to advance the coequal goals of water supply reliability and restoring the Delta ecosystem. Working closely with other agencies and the public, the Council is developing a Delta Levees Investment Strategy (DLIS) to establish priorities for State investments in the Delta levee system. Risk, the potential for an unwanted outcome, is a principal factor in establishing priorities for State investments in levees. Specifically, risk is the probability that an adverse event (such as a flood or earthquake) will occur multiplied by the consequences of that event: Risk = Probability x Consequences As presented in this report, the DLIS is based on a comprehensive methodology that quantifies risk by considering the threats to Delta levees and the assets protected by Delta levees. The DLIS also considers the multiple beneficiaries of Delta levee investments. Building on the results of previous Delta levee planning efforts, the DLIS collects and uses the best available existing data and information from numerous sources to evaluate risks to State interests in the Delta as defined by risk to public safety; property and infrastructure; water supply reliability; the Delta ecosystem; and the unique attributes of the Delta as an evolving place. The DLIS evaluates those risks under current and potential future conditions. In early 2015, the DLIS team prepared an Interim Progress Report summarizing the work conducted during the first 9 months of the DLIS project. The report focused primarily on the methodologies planned for implementing the DLIS project to facilitate a “mid-course” review by an independent science panel, which completed its work in July 2015. Panel members offered comments for improvement and concluded that the “overall methodology of using existing data, identifying important metrics, aggregating results, and making comparisons across islands is conceptually sound” (Mitchell et al. 2015). The DLIS project includes outreach to State and local agencies, concerned stakeholders in the Delta, knowledgeable technical resources, owners and operators of Delta infrastructure, and Delta leaders and residents. The final methodologies employed in the DLIS project are reported herein and incorporate the input from the independent science panel as well as feedback and comments resulting from the outreach efforts.

Delta Region Integrated Flood Management: Key Considerations and Statewide Implications

California Department of Water Resources (DWR) | September 1st, 2012

This Background / Reference Memorandum (BRM) presents highlights from flood-related technical, legislative and funding information regarding the Sacramento-San Joaquin De

This Background / Reference Memorandum (BRM) presents highlights from flood-related technical, legislative and funding information regarding the Sacramento-San Joaquin Delta (Delta), with emphasis on activities by the California Department of Water Resources (DWR). The BRM is intended to provide historical and existing conditions (year 2011) context for DWR’s use in conveying strategies for future investments in integrated flood management in the Delta under a separate document. The State of California has entrusted DWR as the agency with the responsibility for managing water flow through the Delta and for representing State interests in Delta levees. DWR invests in the Delta levee system to protect clear and identifiable State interests, including but not limited to: • Human life, public health, and property within the Delta; • Water quality and water supply for agriculture, ecosystem, and municipal and industrial water users within the Delta and water users outside of the Delta; • Ecosystem protection and enhancement, including protection and recovery of threatened and endangered species; • Critical infrastructure such as highways, railroads, aqueducts, and pumping plants; • Other infrastructure such as transmission lines (electric & petroleum), shipping channels, and public infrastructure (water and wastewater treatment plants); • Agriculture and recreation; and • Cultural, historical, aesthetic, and other values included in “Delta as a place.” State legislation and modifications to the California Water and Public Resources codes have repeatedly demonstrated the State’s interest in preserving the Delta and the importance of Delta levees. The legislation and modifications to the codes have made strong statements about the importance of the Delta, provided direction for the DWR’s levee programs, and provided funding for flood management activities and environmental stewardship in the Delta. This BRM should be considered a reference document. Due to the large number of existing documents on the Delta and its levees, this BRM provides highlights of important material with references to other documents for more detailed information. This base information should be useful when considering modifications to investment strategies for integrated flood management in the Delta.

Delta Vision Strategic Plan

State of California | October 17th, 2008

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less th

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less than to create a vision to repair the ecological damage to the Sacramento-San Joaquin River Delta (Delta), and then prepare a strategic plan which would sustain the Delta in future decades while ensuring a reliable water supply for the two-thirds of California’s population who depend in whole or in part on water from the Delta.

Delta Vision Strategic Plan -- from Phil Isenberg, 1939-2023

State of California | October 17th, 2008

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less th

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less than to create a vision to repair the ecological damage to the Sacramento-San Joaquin River Delta (Delta), and then prepare a strategic plan which would sustain the Delta in future decades while ensuring a reliable water supply for the two-thirds of California’s population who depend in whole or in part on water from the Delta.

Department of the Interior Nature-Based Solutions Roadmap

Nicholas Institute for Energy, Environment & Sustainability (Duke University) | December 1st, 2023

Developing Adaptation Strategies for San Luis Obispo: Preliminary Climate Change Vulnerability Assessment for Social Systems

California Energy Commission (CEC) | July 31st, 2012

San Luis Obispo faces a variety of risks from climate change, including extreme heat, a generally drier climate, increases in extreme weather events, and sea-level rise.

San Luis Obispo faces a variety of risks from climate change, including extreme heat, a generally drier climate, increases in extreme weather events, and sea-level rise. Important vulnerabilities are apparent for water supplies, in agriculture (especially for wine and cattle ranchers) and related tourism, for fishing, coastal tourism, coastal development and infrastructure, and for community services. Certain county populations may face disproportionate risks including the elderly, those already affected by diseases, and outdoor and migrant workers from extreme heat, people living in coastal and inland floodplains, those living at the wildland-urban interface, the student population, institutionalized individuals (especially the state hospital), and those members of the community that tend to be somewhat disenfranchised from public decision-making, such as non-English speaking individuals and those who can’t afford to take off from work to attend public meetings. The county is wise to begin planning and building its adaptive capacity at this time before climate change impacts become more severe, and before there may be greater competition for state and federal financial support for adaptation planning and implementation.

Development of Stage-Frequency Curves in the Sacramento-San Joaquin Delta for Climate Change and Sea Level Rise

California Energy Commission (CEC) | August 27th, 2018

Future changes in hydrologic patterns and sea level rise will impact water levels in the Sacramento-San Joaquin Delta (Delta), the hub of California’s water supply sys

Future changes in hydrologic patterns and sea level rise will impact water levels in the Sacramento-San Joaquin Delta (Delta), the hub of California’s water supply system and an important ecosystem and agricultural area. An important tool for flood management is stage frequency curves which indicate how often certain water levels (or stage) occur. The Delta poses inherent complexity in the determination of stage-frequency and requires a number of considerations. One needs to account for river flows coming into the Delta, as well as the effect of tides from the Delta’s connection to the ocean through San Francisco Bay. During storms, Delta water levels are also affected by storm surge from the advancing storm fronts coming from the Pacific Ocean. Under climate change, Delta water levels will also be affected by rising sea levels and expected changes in hydrology, such as shifts in timing and amount of precipitation and runoff and changes in how much of our precipitation falls as rain or snow (referred to as climate change hydrology in this paper). With these taken into consideration, this study lays out the assumption and method used to develop stage-frequency curves in the Delta for three different conditions: current hydrology conditions, current hydrology with sea level rise, and late-century climate change hydrology with sea level rise. In addition, water surface elevation profiles along the Sacramento and San Joaquin rivers for various magnitudes of flood events were compared to the top of levee elevations. Both the stage-frequency curves and the water surface elevation profiles comparisons to top of levee elevations provide valuable information to water resources planners and were applied to inform life and flood risk analysis for the Delta in the Central Valley Flood Protection Plan 2017 Update.

Development of the Lower Sacramento Valley Flood-Control System: Historical Perspective

American Society of Civil Engineers (ASCE) | July 1st, 2008

Natural physical conditions and the politics of flood management provide the historical context for structural flood control that underlies modern flood hazards in the S

Natural physical conditions and the politics of flood management provide the historical context for structural flood control that underlies modern flood hazards in the Sacramento Valley. The valley is a broad, low plain with backswamp basins that were frequently inundated prior to Anglo-American settlement, continuing until the modern flood-control system was established. Early attempts to emulate the Mississippi River single-channel levee strategy failed repeatedly in the Sacramento Valley due to high flow variability, mining sedimentation, lack of a coordinated levee system, and the inability of the main channels to carry most of the flood flows. Hydraulic mining caused massive sedimentation in major east-side tributaries, such as the Feather, Yuba, Bear, and American Rivers, and in the Sacramento River below the Feather River confluence. This sedimentation led to a flood-control design that relied on levees with narrow cross-channel spacings to promote channel scour and facilitate navigation. Even without sedimentation, floods were not contained within channels, but were largely conveyed through a system of low-land basins. In the early twentieth century, an innovative channel bypass system was adopted that emulates the natural system by routing excess flood waters over a series of weirs and through broad, channelized bypasses that cross the basins. This system has been successful in reducing the extent of frequent inundations of broad lowland areas of the valley. It is in need of maintenance and improvement, however, and cannot eliminate the risk of future flooding in low areas behind levees that are being rapidly developed.