San Joaquin River

Will Tidal Wetland Restoration Enhance Populations of Native Fishes?

University of California, Davis (UC Davis) | July 31st, 2003

Restoration of tidal wetlands might enhance populations of native fishes in the San Francisco Estuary of California. The purpose of this paper is to: (1) review the curre

Restoration of tidal wetlands might enhance populations of native fishes in the San Francisco Estuary of California. The purpose of this paper is to: (1) review the currently available information regarding the importance of tidal wetlands to native fishes in the San Francisco Estuary, (2) construct conceptual models on the basis of available information, (3) identify key areas of scientific uncertainty, and (4) identify methods to improve conceptual models and reduce uncertainty. There are few quantitative data to suggest that restoration of tidal wetlands will substantially increase populations of native fishes. On a qualitative basis, there is some support for the idea that tidal wetland restoration will increase populations of some native fishes; however, the species deriving the most benefit from restoration might not be of great management concern at present. Invasion of the San Francisco Estuary by alien plants and animals appears to be a major factor in obscuring the expected link between tidal wetlands and native fishes. Large-scale adaptive management experiments (>100 hectares) appear to be the best available option for determining whether tidal wetlands will provide significant benefit to native fishes. Even if these experiments are unsuccessful at increasing native fish populations, the restored wetlands should benefit native birds, plants, and other organisms.

Willingness to Pay to Protect Wetlands and Reduce Wildlife Contamination from Agricultural Drainage

Springer | December 2nd, 1991

This chapter presents the results of a survey of the general population in California regarding their willingness to pay for alternative programs to protect and expand we

This chapter presents the results of a survey of the general population in California regarding their willingness to pay for alternative programs to protect and expand wetlands as well as reduce wildlife contamination in the San Joaquin Valley (Valley). The results of 803 completed interviews from 1,573 successfully contacted households indicate that Californians would pay $154 each year in higher taxes to purchase water to prevent a decrease in wetland acreage from 85,000 acres to 27,000 acres. This value rose to $254 to provide foran increase in wetland acreage to 125,000 acres with an associated 40 percent increase of bird populations. California households would pay $313 each year in additional taxes to implement agricultural drainage programs that would reduce waterbirds exposure to contamination from 70 percent to 20 percent exposure. The water management implication of these results is that Californians value clean water supplies for refuges at over $3 billion a year.

Wind Over San Francisco Bay and the Sacramento-San Joaquin River Delta: Forcing for Hydrodynamic Models.

San Francisco Estuary Institute (SFEI) | March 25th, 2019

The Ludwig wind model (Ludwig et al., 1991; Ludwig and Sinton, 2000) has been used to generate spaio-temporally varying wind inputs for hydrodynamic models of the San Fr

The Ludwig wind model (Ludwig et al., 1991; Ludwig and Sinton, 2000) has been used to generate spaio-temporally varying wind inputs for hydrodynamic models of the San Francisco Bay and Sacramento-San Joaquin River Delta (SFB-Delta) in recent projects at Deltares (Achete et al., 2015), at the United States Geological Survey (USGS; Martyr-Koller et al., 2017), and at San Francisco Esturary Institute (SFEI; Nuss et al., 2018). These projects all utilize hydrodynamic models in the Deltares suite of software known as DFlow (e.g., Deltares, 2019), and the wind inputs to DFlow are specied hourly on a 1.5 km x 1.5 km grid.

Winter melt trends portend widespread declines in snow water resources

Nature Portfolio (Springer Nature) | April 5th, 2021

In many mountainous regions, winter precipitation accumulates as snow that melts in the spring and summer, which provides water to one billion people globally. Climate wa

In many mountainous regions, winter precipitation accumulates as snow that melts in the spring and summer, which provides water to one billion people globally. Climate warming and earlier snowmelt compromise this natural water storage. Although snowpack trend analyses commonly focus on the snow water equivalent (SWE), we propose that trends in the accumulation season snowmelt serve as a critical indicator of hydrological change. Here we compare long-term changes in the snowmelt and SWE from snow monitoring stations in western North America and find 34% of stations exhibit increasing winter snowmelt trends (P < 0.05), a factor of three larger than the 11% showing SWE declines (P < 0.05). Snowmelt trends are highly sensitive to temperature and an underlying warming signal, whereas SWE trends are more sensitive to precipitation variability. Thus, continental-scale snow water resources are in steeper decline than inferred from SWE trends alone. More winter snowmelt will complicate future water resource planning and management.

Working Draft Scientific Basis Report for New and Revised Flow Requirements on the Sacramento River and Tributaries, Eastside Tributaries to the Delta, Delta Outflow, and Interior Delta Operations

California State Water Resources Control Board (SWRCB) | October 14th, 2016

This working draft Scientific Basis Report (Report) is being prepared to support the update of the Bay-Delta Plan’s protection of fish and wildlife beneficial uses in t

This working draft Scientific Basis Report (Report) is being prepared to support the update of the Bay-Delta Plan’s protection of fish and wildlife beneficial uses in the Sacramento River watershed and related areas, known as Phase II.1 This update considers four categories of requirements: (1) new inflow requirements for the Sacramento River, its tributaries, and eastside tributaries to the Delta; (2) changes to Delta outflow requirements; (3) new and modified interior Delta flow requirements; and (4) new requirements for cold water habitat. A comprehensive regulatory approach is needed that protects Bay-Delta fish and wildlife throughout their migratory range, and that better integrates the regulatory framework addressing inflows, outflows, and water project operations. Such a framework will help avoid overreliance on one stream to meet flow and other water quality requirements by providing necessary flows on multiple tributaries to ensure suitable habitat and migratory pathways upstream of the Bay-Delta. Another goal is to employ a strategy that provides for timely action, flexibility, and integration with other planning, science, restoration, and regulatory efforts so action can be taken before imperiled species in the watershed are no longer able to be restored.

Workshop on Delta Outflows and Related Stressors Panel Summary Report

Delta Stewardship Council (Delta Council) | May 15th, 2014

This report was prepared as part of the State Water Resources Control Board’s (“Board”) process of developing and implementing updates to the Bay-Delta Plan and flo

This report was prepared as part of the State Water Resources Control Board’s (“Board”) process of developing and implementing updates to the Bay-Delta Plan and flow objectives to protect beneficial uses in the Bay-Delta Watershed. The focus of this report is Delta outflows and related stressors. The report is based upon reading extensive background materials selected by the Delta Science Program as well as materials identified by individual Panel members to be relevant, a two-day public meeting that included a number of presentations and during which public comments were received by the Panel, review of some of the materials provided during and after the meeting, and the Panel’s internal discussion and deliberations. The Board conducted a review of the current 2006 Bay-Delta Plan in 2009 and determined that Delta outflows and other requirements for the protection of fish and wildlife beneficial uses should be considered for revision. “Delta Outflows and Related Stressors” was further identified by the Delta Science Program as one of four topics emerging from a series of Board workshops in 2012 for which additional workshops should be conducted to provide input on the best available scientific information. Delta outflows and their management have been the subject of extensive scientific and management discussion for decades. A benchmark in this discourse is the report from a series of technical workshops facilitated by Dr. Jerry Schubel (Schubel et al. 1993). Schubel notes in the preface to that report that estuarine standards are required to protect the estuarine ecosystem from “further degradation” until “debate and disagreement over the relative importance of the benefits of low salinity habitat and therefore of flow, on the one hand, and of the liabilities of the physical diversion of a portion of that flow and the associated processes of entrainment of organisms, on the other,” can be resolved with a degree of scientific certainty acceptable to the Board. To some extent, this Panel has been asked to revisit whether standards for Delta outflow are still required, and to identify the degree of scientific certainty regarding the importance of Delta outflow to the ecosystem relative to other stressors.

Workshop report—Earthquakes and High Water as Levee Hazards in the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | September 30th, 2016

Your Delta, Your Voice

California Department of Water Resources (DWR) | May 28th, 2021

In Fall 2020, the California Department of Water Resources (DWR) launched an environmental justice community survey entitled Your Delta, Your Voice. The survey was live f

In Fall 2020, the California Department of Water Resources (DWR) launched an environmental justice community survey entitled Your Delta, Your Voice. The survey was live from September 30 through December 11, 2020. Survey development and outreach was led by Ag Innovations and supported by numerous partners and agency staff. The survey had the following goals: 1) to gather information from disadvantaged communities in the Delta region about how they work, live, recreate and experience the Delta, 2) to understand how the community values and uses its natural, economic, and social resources, and 3) increase awareness of the proposed project and interest in participating in public engagement among disadvantaged community members in the Delta region. These goals were pursued in order to inform the proposed Delta Conveyance Project environmental review and planning process, with a particular emphasis on the environmental justice chapter of the CEQA Environmental Impact Report. Ag Innovation’s intent was to faithfully reflect the input and perspectives gathered via the survey within this report. In January 2021, DWR began developing a Delta Conveyance Project Community Benefits Program. The information gathered from the survey will also be used to inform DWR’s efforts to work towards community benefits in the Delta region, although that was not part of the original intent of the survey as the program did not exist at that time.