San Francisco Bay

Extreme Precipitation-Temperature Scaling in California: The Role of Atmospheric Rivers

American Geophysical Union (AGU) | July 25th, 2023

Facilitating Adaptive Management in California’s Sacramento–San Joaquin Delta

University of California, Davis (UC Davis) | July 1st, 2017

Uncertainties in understanding ecosystems increase the risk that management will fail to achieve desired results. Adaptive management is a structured, iterative applicati

Uncertainties in understanding ecosystems increase the risk that management will fail to achieve desired results. Adaptive management is a structured, iterative application of science-based knowledge to reduce uncertainties and build flexibility into decision-making. However, adaptive management is more easily planned than implemented, and it is only beginning to be applied in the California’s Sacramento–San Joaquin Delta. We draw from two assessments of adaptive management in the Delta and examples of its use elsewhere to suggest how the process can be facilitated. Although a highly structured adaptive-management process may not always be needed, several elements are essential. Adaptive management should begin by clearly identifying the problem, goals, and objectives; recognizing uncertainties; identifying decision points and alternative approaches; recognizing when adjustments are needed and having the flexibility to make them; and considering societal and political constraints. Model complexity should be matched to that of the system and management needs; experiments can help unravel causal relationships. Monitoring, analyses, and syntheses require comprehensive data-management systems. More frequent and organized communications among scientists, managers, stakeholders, and decision-makers are necessary. We propose the establishment of an “Adaptive Management Team” to coordinate efforts across the management spectrum of the Delta and to provide guidance and link individual projects to shared approaches and experiences. Reliable long-term support will be needed to assess results of management actions, adjust approaches where improvement is likely, and strive toward the legislated goals of enhancing the Delta ecosystem while also providing reliable water supplies to much of California, and doing both these things in a manner that protects values of the Delta as a place where people live and work. 

Factors Affecting Marsh Vegetation at the Liberty Island Conservation Bank in the Cache Slough Region of the Sacramento–San Joaquin Delta, California

U.S. Geological Survey (USGS) | July 5th, 2017

The Liberty Island Conservation Bank (LICB) is a tidal freshwater marsh restored for the purpose of mitigating adverse effects on sensitive fish populations elsewhere in

The Liberty Island Conservation Bank (LICB) is a tidal freshwater marsh restored for the purpose of mitigating adverse effects on sensitive fish populations elsewhere in the region. The LICB was completed in 2012 and is in the northern Cache Slough region of the Sacramento–San Joaquin Delta. The wetland vegetation at the LICB is stunted and yellow-green in color (chlorotic) compared to nearby wetlands. A study was done to investigate three potential causes of the stunted and chlorotic vegetation: (1) improper grading of the marsh plain, (2) pesticide contamination from agricultural and urban inputs upstream from the site, (3) nitrogen-deficient soil, or some combination of these. Water samples were collected from channels at five sites, and soil samples were collected from four wetlands, including the LICB, during the summer of 2015. Real-time kinematic global positioning system (RTK-GPS) elevation surveys were completed at the LICB and north Little Holland Tract, a closely situated natural marsh that has similar hydrodynamics as the LICB, but contains healthy marsh vegetation. The results showed no significant differences in carbon or nitrogen content in the surface soils or in pesticides in water among the sites. The elevation survey indicated that the mean elevation of the LICB was about 26 centimeters higher than that of the north Little Holland Tract marsh. Because marsh plain elevation largely determines the hydroperiod of a marsh, these results indicated that the LICB has a hydroperiod that differs from that of neighboring north Little Holland Tract marsh. This difference in hydroperiod contributed to the lower stature and decreased vigor of wetland vegetation at the LICB. Although the LICB cannot be regraded without great expense, it could be possible to reduce the sharp angle of the marsh edge to facilitate deeper and more frequent tidal flooding along the marsh periphery. Establishing optimal elevations for restored wetlands is necessary for obtaining the full suite of ecosystem services provided by tidal wetlands. A better system of tidal benchmarks throughout the delta is needed to help restoration practitioners correctly grade the elevation of newly restored wetlands.

Factors and Processes Affecting Delta Levee System Vulnerability

University of California, Davis (UC Davis) | December 1st, 2016

The authors appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils over time has cause

The authors appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils over time has caused a gradual sinking which contributed to internal levee failures. Although these subsidence rates have decreased with time, they still contribute to levee instability. Additional data is needed to assess spatial and temporal effects of subsidence caused by peat thinning and deformation. Since the mid-1970s large-scale, State investments in levee upgrades have increased conformance, however accounts continue to conflict on how these investments correspond to the numbers of failures. Both modeling and history suggest that the projected increases of high-flow frequency associated with climate change will increase levee-failures rates. Quantification of this increased threat requires further research. A reappraisal of seismic threats resulted in updated ground motion estimates for multiple faults and earthquake occurrence frequencies. The immediate seismic threat, liquefaction, is the sudden loss of strength due to an increase in the pressure of the pore fluid and corresponding loss of contact forces. However, levees damaged during an earthquake that do not immediately fail, may eventually breach. Consequences for future levee failure are estimated to cost up to billions of dollars. The analysis of future risks will benefit from more detailed descriptions of levee strength and upgrades, consideration of subsidence, climate change, and earthquake threats. Ecosystem benefits of levee habitats in this highly altered system are thin. Better recognition and coordination is needed among the creation of high value habitats, levee needs, costs, benefits of levee improvements, and breaches.  

Facts on the Water Rights Question in the Central Valley Project

California Farm Bureau (CFB) | March 11th, 1948

Federal Investments for the California Bay-Delta Region

U.S. Department of the Interior (DOI) | February 5th, 2014

The San Francisco Bay/Sacramento-San Joaquin Delta (Bay-Delta) region of California is an ecosystem of national significance. It is also the hub of the nation’s largest

The San Francisco Bay/Sacramento-San Joaquin Delta (Bay-Delta) region of California is an ecosystem of national significance. It is also the hub of the nation’s largest water delivery system—infrastructure that is the foundation for economic activity in the agricultural, industrial, and recreational sectors of the economy, and provides drinking water to a population of over 25 million Californians. This document is intended to provide an overview of the federal land and water programs in and around the Bay-Delta region, their purpose, options for future programs or actions, and an overview of the actions in which agencies are engaged already. Successful long term management of water resources and the environment to achieve the co-equal goals of the Bay Delta Conservation Plan (BDCP) and overall Delta sustainability requires continued improvement in managing California’s finite water supply. Contents I. Introduction II. Bay Delta-Big Picture: A Holistic Approach • State and Federal Integrated Water Management • Reducing Water Demand • Increasing Water Reliability and Supply • Improve Operational Efficiency and Transfers/Exchanges • Potential Federal Water and Ecosystem Management Actions III. Role of the Federal agencies • Department of the Interior Bureau of Reclamation U.S. Fish and Wildlife Service • Environmental Protection Agency • Department of Commerce National Oceanic and Atmospheric Administration • Army Corps of Engineers • Department of Agriculture Natural Resource Conservation Service U.S. Forest Service Rural Development Farm Services Agency Agriculture Research Service IV. Conclusion

Field Operations Manual for the Regional Monitoring Program (Version 1, Sediment)

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

This Field Operations Manual (FOM) of the Regional Monitoring Program (RMP) is intended as a reference document for each sampling effort. The FOM describes in detail how

This Field Operations Manual (FOM) of the Regional Monitoring Program (RMP) is intended as a reference document for each sampling effort. The FOM describes in detail how field staff should collect water, sediment, bivalve, bird egg, and sport fish samples for all RMP sampling efforts.  Sampling conducted by the RMP should also reference the QA Program Plan (QAPP) document, which describes the entire program, and is the repository for details about laboratories, analytical methods, MDLs, sample handling, sample preservation, and quality assurance procedures. The FOM is a companion document to the QAPP, and provides a more detailed description of sampling methods that are only outlined in Section 11 of the QAPP.  In addition, each individual sampling effort will have a unique Cruise Plan or Sampling and Analysis Plan (SAP). The SAP describes the details of each sampling effort, including dates, times, places, and staff, as well as the parameters that are being collected and analyzed. The SAP will reference this FOM for the detailed sampling methods. If different sampling methods are needed for a particular study, the SAP will describe deviations from the normal methods described in the FOM. 

Final Environmental Impact Report for Adoption of a Regulation for the Hexavalent Chromium Maximum Contaminant Level

California State Water Resources Control Board (SWRCB) | April 17th, 2024

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.),

As the lead agency in accordance with sections 15089 and 15132 of the California Environmental Quality Act (CEQA) Guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.), this document is the Final Environmental Impact Report (Final EIR) for the adoption of statewide regulations setting the maximum contaminant level (MCL) for hexavalent chromium (Proposed Regulations). The Proposed Regulations include a maximum contaminant level (MCL) of 10 μg/L for hexavalent chromium. (Cal. Code Regs. tit. 22, § 64431 Table 64431-A.) The Proposed Regulations also include a compliance schedule based on public water system size, by adding subdivision (p) and Table 64432-B to section 64432 of title 22 of the California Code of Regulations, identifies a detection limit for purposes of reporting, sets monitoring and reporting requirements and public notice requirements for violations of the MCL, and establishes the Best Available Technologies (BAT) for treating hexavalent chromium in drinking water. California State Water Resources Control Board (SWRCB) Chrom VI MCL rulemaking chronology.

Final Environmental Impact Statement: Long-Term Operation of the Central Valley Project and State Water Project Central Valley Project, California

U.S. Bureau of Reclamation (USBR) | November 15th, 2024

The United States Department of the Interior, Bureau of Reclamation (Reclamation) prepared this environmental impact statement (EIS) for the 2021 Endangered Species Act R

The United States Department of the Interior, Bureau of Reclamation (Reclamation) prepared this environmental impact statement (EIS) for the 2021 Endangered Species Act Reinitiation of Section 7 Consultation on the Long-Term Operation of the Central Valley Project (CVP) and State Water Project (SWP). This EIS is meant to inform the public and decision makers on potential federal actions by examining a range of reasonable alternatives and the potential effect on the environment. Reclamation manages the CVP. The California Department of Water Resources (DWR) manages the SWP. Collectively, the operation of the CVP and SWP provides flood control and navigation; delivers water to 30 million people; supports 4 million acres of agriculture; maintains 19 wildlife refuges on the Pacific Flyway; protects numerous iconic and endemic species such as Chinook salmon, coho salmon, steelhead, sturgeon, and smelt; generates 4.5 million megawatt hours of electricity; maintains water quality for beneficial uses in the San Francisco Bay/Sacramento–San Joaquin Delta Estuary (Bay-Delta); and supports recreation throughout Northern California. 

Final Sensitive Beneficial Use Literature Review (Task 3.1.1)

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-Salts) | May 16th, 2023