Scientific Basis Report in Support of New and Modified Requirements for Inflows from the Sacramento River and its Tributaries and Eastside Tributaries to the Delta, Delta Outflows, Cold Water Habitat, and Interior Delta Flows

California State Water Resources Control Board (SWRCB) | October 2nd, 2017

The State Water Board is conducting a review and update of the 2006 Bay-Delta Plan to ensure that beneficial uses of water in the Bay-Delta watershed are reasonably prote

The State Water Board is conducting a review and update of the 2006 Bay-Delta Plan to ensure that beneficial uses of water in the Bay-Delta watershed are reasonably protected. Phase I addresses potential changes to San Joaquin River flow requirements for the protection of fish and wildlife and potential changes to southern Delta salinity requirements for the protection of agriculture.1 Phase II addresses changes to the Bay-Delta Plan to protect native fish and wildlife in the Sacramento River, Delta, and associated tributaries. This Scientific Basis Report (Science Report or Report) is being prepared to support the Phase II update of the Bay-Delta Plan. It describes the science on which proposed changes to the Bay-Delta Plan will be based. A working draft version of the Report was released on October 19, 2016, to receive early scientific and public input on the science related to Phase II prior to submittal of the Report for external peer review. The State Water Board received input from a number of interested parties including water users; environmental groups; and local, state, and federal agencies. In recognition of the vision for “one Delta, one science” articulated in the Delta Stewardship Council’s (DSC) Delta Plan, the State Water Board also requested that the Delta Independent Science Board (Delta ISB) conduct a review of the Report. The State Water Board appreciates the valuable comments and suggestions that have helped further strengthen the scientific content in this version of the Report. In addition, comments related to regulatory and policy issues were raised that have further informed the development of proposed changes to the Bay-Delta Plan, including implementation approaches. The general components of these changes are summarized below and in more detail in Chapter 5 for context, and will continue to be refined as the planning process moves forward. This Report and the peer reviewers’ responses will be posted on the State Water Board web site and become part of the record for this Bay-Delta Plan update. Content from this Report will be included in a larger Staff Report that will also contain information on environmental, economic, and other analyses of potential changes to the Bay-Delta Plan, including regulatory and policy considerations of competing uses of water (including municipal, industrial, agricultural, power production, and other environmental uses of water such as wetland and wildlife refuge supplies). These issues are not addressed in this Science Report. Further, while a description of the approach for proposed changes to the Bay-Delta Plan is provided, the exact regulatory language is still under development and will be informed by the science in this Report and other information that will be included in the Staff Report. The public and agencies will continue to have opportunities to provide input throughout this process.

Scrutinizing the Delta Cross Channel

CALFED | June 1st, 2001

Sea Level Rise Impacts on Wastewater Treatment Systems Along the U.S. Coasts

American Geophysical Union (AGU) | April 13th, 2018

Wastewater treatment plants are susceptible to flooding resulting from sea level rise. Previous estimates of wastewater exposure have only considered the impacts of mar

Wastewater treatment plants are susceptible to flooding resulting from sea level rise. Previous estimates of wastewater exposure have only considered the impacts of marine flooding at the local or regional scale. In this analysis, we quantify the exposure to marine flooding across the coastal United States and then consider the relative impacts of marine and groundwater flooding at the regional scale in the San Francisco Bay Area. We also estimate the number of people who may lose access to wastewater services if no actions are taken to prevent flooding at wastewater treatment plants. We find that the number of people impacted by sea level rise due to loss of wastewater services could be five times as high as previous predictions of the number of people who experience direct flooding of their homes or property. We also find that groundwater flooding poses a significant threat to wastewater plants in the San Francisco Bay region.

Sea Level Variations of the United States 1854–2006

National Oceanic and Atmospheric Administration (NOAA) | December 19th, 2009

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relat

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relative to homes, levees, and other coastal infrastructure were accurately referenced to sea level. In support of this mission, NOAA’s Center for Operational Oceanographic Products and Services and its predecessors have determined sea level for the United States since the mid 19th Century. While climate change was not a concern during the mid-1800s, the accurate determination of sea level was critical for navigation and marine boundary determination. To meet these important requirements, technology, procedures, and processes were developed to the highest scientific and engineering standards. At the turn of the 20th Century it was realized that there was a need to account for a rise in sea level and the first National Tidal Datum Epoch was established. Today this Epoch is updated every 20 to 25 years. The Supreme Court recognized these standards and procedures in the landmark 1936 case of Borax, Ltd v. City of Los Angeles when legally defining sea level. Due to those initial efforts and the continued dedication of those charged with the responsibility for monitoring sea level for the United States, we can accurately determine relative (local) mean sea level along the Nation’s coastline today. These observations also play an important role in monitoring change in global sea level. As we monitor change in sea level into the 21st Century, the statement made by Alexander Dallas Bache, the Second Superintendent of the Coast Survey, is as relevant today as when it was stated more than 150 years ago, “It seems a very simple task to make correct tidal observations; but, in all my experience, I have found no observations which require such constant care and attention” (1854). Michael Szabados, Director, Center for Operational Oceanographic Products and Services

SediMatch Factsheet

San Francisco Estuary Institute (SFEI) | June 1st, 2018

 SediMatch is a collaborative program of the San Francisco Bay Joint Venture (SFBJV), the San Francisco Bay Conservation and Development Commission (BCDC), the San Franc

 SediMatch is a collaborative program of the San Francisco Bay Joint Venture (SFBJV), the San Francisco Bay Conservation and Development Commission (BCDC), the San Francisco Estuary Institute (SFEI), the San Francisco Estuary Partnership (SFEP), and others to bring together the wetland habitat restoration, flood control, and dredging communities to discuss challenges and find mutually beneficial strategies to increase reuse of dredged sediment at habitat restoration sites. 

Sharing the Cost: Accelerating Water Resilience through Infrastructure Finance in California

Milken Institute | December 12th, 2022

Sharpening of cold-season storms over the western United States

Nature Portfolio (Springer Nature) | January 19th, 2023

Winter storms are responsible for billion-dollar economic losses in the western United States. Because storm structures are not well resolved by global climate models, it

Winter storms are responsible for billion-dollar economic losses in the western United States. Because storm structures are not well resolved by global climate models, it is not well established how single events and their structures change with warming. Here we use regional storm-resolving simulations to investigate climate change impact on western US winter storms. Under a high-emissions scenario, precipitation volume from the top 20% of winter storms is projected to increase by up to 40% across the region by mid-century. The average increase in precipitation volume (31%) is contributed by 22% from increasing area coverage and 19% from increasing storm intensity, while a robust storm sharpening with larger increase in storm centre precipitation compared with increase in storm area reduces precipitation volume by 10%. Ignoring storm sharpening could result in overestimation of the changes in design storms currently used in infrastructure planning in the region.

Stacked Incentives: Co-Funding Water Customer Incentive Programs

Pacific Institute | June 1st, 2021

Water utilities throughout the United States offer customer incentives to motivate action and foster engagement. Incentive programs can take many forms, such as rebate

Water utilities throughout the United States offer customer incentives to motivate action and foster engagement. Incentive programs can take many forms, such as rebates for high-efficiency fixtures and appliances, technical assistance for installing cisterns and rain gardens, and educational programs about water reuse. In addition to providing water-related benefits, many of these programs generate additional co-benefits, including reductions in energy use for heating or treating water and wastewater, increased carbon sequestration in landscapes, enhancements to local biodiversity, and more. These co-benefits present water utilities with an opportunity to build collaborative partnerships and co-funding for customer incentive programs through “stacked incentives.”

State of California Sea-Level Rise Guidance—2018 Update

Ocean Protection Council (OPC) | March 4th, 2018

This updated document, the “State of California Sea-Level Rise Guidance” (Guidance), provides a bold, science-based methodology for state and local governments to ana

This updated document, the “State of California Sea-Level Rise Guidance” (Guidance), provides a bold, science-based methodology for state and local governments to analyze and assess the risks associated with sea-level rise, and to incorporate sea-level rise into their planning, permitting, and investment decisions. This Guidance provides:  A synthesis of the best available science on sea-level rise projections and rates for California;  A step-by-step approach for state agencies and local governments to evaluate those projections and related hazard information in decision making; and  Preferred coastal adaptation approaches. 

State Plan of Flood Control Descriptive Document 2016 Update

California Department of Water Resources (DWR) | December 14th, 2016

The November 2016 State Plan of Flood Control (SPFC) Descriptive Document Update (2016 Update) is intended to serve as a reference for flood management planners and opera

The November 2016 State Plan of Flood Control (SPFC) Descriptive Document Update (2016 Update) is intended to serve as a reference for flood management planners and operators at the local, State, and federal levels. It is not a stand-alone document; rather, it works in conjunction with the November 2010 SPFC Descriptive Document, builds upon information presented in the original report, and documents changes to the SPFC that have occurred between November 2010 and July 2016. The 2016 Update documents the inventory of flood control projects and works (facilities), lands, programs, plans, conditions, and mode of operations and maintenance for the State-federal flood management system in the Sacramento River and San Joaquin River watersheds of California, as well as informs the 2017 Central Valley Flood Protection Plan Update. In 2006 and 2007, California voters approved the Disaster Preparedness and Flood Prevention Bond Act of 2006 and the Central Valley Flood Protection Act of 2008 respectively. These acts defined the Sacramento River and San Joaquin River federal-State flood control projects as the SPFC, and required DWR to develop, and the Central Valley Flood Protection Board to adopt, a Central Valley Flood Protection Plan. The Central Valley Flood Protection Plan is broader than the SPFC, affecting the entire watersheds of the Sacramento and San Joaquin valleys. A complex system of dams and reservoirs, levees, weirs, bypasses, and other features constructed piecemeal over the last 100 years protects urban and rural areas against most flooding. This system has prevented billions of dollars in damage in its lifetime. A portion of this complex flood protection system includes State and federally authorized projects for which the Central Valley Flood Protection Board or DWR has provided assurances of cooperation to the federal government, known as the SPFC. These statutory authorizations include provisions regarding responsibility for operation and maintenance of the flood control facilities. The California Legislature has authorized funding for numerous flood control projects throughout the Sacramento and San Joaquin River watersheds. As the SPFC evolves, updates to the SPFC Descriptive Document will be useful in determining funding eligibility for funding for facility improvements. RELATED DOCUMENT:  State Plan of Flood Control (2010)