Expert review of the sediment screening guidelines for the beneficial reuse of dredged material in San Francisco Bay, Workshop Summary Report

Publisher not available | March 17th, 2020

Exploring scientific and management implications of upper trophic level food webs in the Delta

Delta Stewardship Council (Delta Council) | April 17th, 2024

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defi

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defined as the network of species interactions (competition, predation) and interactions with their environment that are related through the flow of energy through the ecosystem (e.g., Paine 1980). Physical modifications, in addition to the introduction of non-native species and the changing climate, have significantly altered the structure and energetic pathways of the food webs for decades. The science clearly suggests that predicting the impacts of habitat restoration, fisheries, changes in environmental drivers (e.g., climate, changes in nutrient loading, invasive species) on the ecological carrying capacity and productivity of the Delta, as well as the bioaccumulation of contaminants on species or the ecosystem, requires an understanding of food web processes.

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 Affecting the Composition and Salinity of Exports from the South Sacramento-San Joaquin Delta

California Department of Water Resources (DWR) | February 24th, 2004

The goal of this report is to identify factors affecting the composition and salinity of exports from the south Sacramento-San Joaquin Delta.  Composition is defined her

The goal of this report is to identify factors affecting the composition and salinity of exports from the south Sacramento-San Joaquin Delta.  Composition is defined here as sources of salt such as rivers and seawater. The individual objectives are to Review south Delta export composition studies; Describe the salinity trends in cross-Delta flow and the San Joaquin River - the two immediate sources of water flowing to the SWP and CVP export sites in the south Delta; Identify factors determining the export of cross-Delta flow versus the San Joaquin River; and Describe long-term salinity trends in SWP exports from the south Delta and factors affecting them.  

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

Feasibility Study for a Sacramento-San Joaquin Delta National Heritage Area

Delta Protection Commission (DPC) | June 4th, 2012

In Fall 2009, the California State Legislature passed a comprehensive package reforming governance of the Sacramento-San Joaquin Delta (Delta) and related aspects of stat

In Fall 2009, the California State Legislature passed a comprehensive package reforming governance of the Sacramento-San Joaquin Delta (Delta) and related aspects of statewide water management. In Section 85301 of Senate Bill X7-1 (Delta Reform Act of 2009), the Legislature charged the Delta Protection Commission (DPC) with developing: “A proposal to protect, enhance, and sustain the unique cultural, historical, recreational, agricultural, and economic values of the Delta as an evolving place....The Commission shall include in the proposal a plan to establish state and federal designation of the Delta as a place of special significance, which may include application for a federal designation of the Delta as a National Heritage Area.” This feasibility study has been undertaken in order to fulfill this legislative mandate, which upon acceptance of this study by the DPC, it will be submitted to a Delta Congressional Representative to introduce legislation to establish a Delta National Heritage Area (NHA). The study inventories and describes resources of the region which are supportive of the proposed NHA’s story and themes that make the area a place of national significance. The study also proposes how the NHA will be managed and organized to coordinate heritage area activities. Additionally, local groups who support the NHA are listed, along with letters of support; and organizations who are interested in potentially serving as partners on NHA activities are described, along with letters of partnership commitment. During the course of this process a separate effort was initiated to establish a Delta NHA. In January 2011, Senator Dianne Feinstein introduced legislation into the Senate, with companion legislation introduced by Congressman John Garamendi into the House of Representatives to designate a Delta NHA, with the DPC as the management entity. The DPC has been monitoring the progress of this legislation while continuing to work on this feasibility study. A NHA is a place designated by the United States Congress where natural, cultural, historical and recreational resources combine to form a cohesive, nationally-distinctive landscape arising from patterns of human activity shaped by geography. These areas tell nationally important stories about our nation and are representative of the national experience through both the physical features that remain and the traditions that have evolved within them. The DPC developed this study with a process that incorporated public involvement throughout its entirety. A variety of activities were undertaken to acquire stakeholder input, including: public meetings, public presentations, stakeholder interviews, public review memos, and project study team meetings.

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.