Reinitiation of Consultation on the Coordinated Long-Term Modified Operations of the Central Valley Project and State Water Project

U.S. Bureau of Reclamation (USBR) | February 18th, 2020

U.S. Bureau of Reclamation ROD index page

U.S. Bureau of Reclamation ROD index page

Relationship of Delta Cross Channel Gate Operations to Loss of Juvenile Winter-run Chinook Salmon at the CVP/SWP Delta Facilities

California Department of Fish and Wildlife (CDFW) | July 1st, 2003

Winter-run Chinook salmon are distinguishable from the three other Chinook runs in the Sacramento River system by the timing of their upstream migration and spawning. Due

Winter-run Chinook salmon are distinguishable from the three other Chinook runs in the Sacramento River system by the timing of their upstream migration and spawning. Due to precipitous decline in the population from the late 1960’s through the late 1980’s, NOAA Fisheries listed the run as “threatened” in August 1989, and subsequently reclassified the run as “endangered” in 1992. The state of California listed the run as endangered in 1989.  Many factors contributed to the decline in the winter-run Chinook population. Among these factors, operation of the federal Central Valley Project and State Water Project has had continuing impacts on winter-run Chinook. Of particular concern have been the direct entrainment losses of juvenile winter-run Chinook at the project export facilities in the Delta. 

Report on the Delta Drought Response Pilot Program for Water Year 2023

Sacramento-San Joaquin Delta Conservancy | July 24th, 2024

This report describes the 2023 Delta Drought Response Pilot Program (DDRPP/Program), provides an analysis of the Program’s effectiveness, and describes the Program outc

This report describes the 2023 Delta Drought Response Pilot Program (DDRPP/Program), provides an analysis of the Program’s effectiveness, and describes the Program outcomes, including findings and recommendations for application in future agricultural water conservation programs. The DDRPP launched in January 2022 as a response to the continuing risk of drought in the Sacramento-San Joaquin Delta Watershed. This report focuses on the results of the 2023 Program, with a brief analysis comparing both years of the Program. For detailed information on the 2022 Program and 2022 analysis, see the 2022 DDRPP Final Report (Sacramento-San Joaquin Delta Conservancy, 2023).

Response to the Delta Science Program and Independent Review Panel Report from the 2015 Annual Review of the Long-term Operation Biological Opinions (2015 Annual Review) (January 29, 2016)

Delta Stewardship Council (Delta Council) | January 29th, 2016

Responsible Exports Plan

Environmental Water Caucus | May 29th, 2013

The consensus diagnosis for the Delta estuary is dire. The California Environmental Water Caucus prescribes more river flows and reduced fresh water exports to help the D

The consensus diagnosis for the Delta estuary is dire. The California Environmental Water Caucus prescribes more river flows and reduced fresh water exports to help the Delta recover. The EWC’s plan demonstrates how water supply reliability can be improved while reducing exports from the Bay Delta Estuary. Many of our recommendations have been presented to the Delta Stewardship Council as part of Alternative 2 for the Delta Plan. We have now packaged this series of related actions into a single alternative for evaluation in any future NEPA or CEQA evaluations, or by the State Water Resources Control Board. The actions are largely based on the EWC report California Water Solutions Now, (www.ewccalifornia.org), which can be referenced for supporting details. This package of actions (“The RX Plan”) represents the EWC alternative to the BDCP. The RX Plan includes a unique combination of actions that will open the discussion for alternatives to the currently failed policies which continuously attempt to use water as though it were a limitless resource. The RX Plan is about far more than just reduced exports. The uniqueness of this Plan is that while it will reduce the quantity of water exported from the Bay Delta Estuary, in order to protect the health of the Estuary’s habitat and fisheries with increased inflows and outflows, it also contains actions that will reduce the demand for water and increase supplies for exporters south of the Delta in order to compensate for the reduced south-of-Delta exports. It is the only extant plan that will modernize existing facilities in the Bay-Delta with improved fish screens at the South Delta, levees reinforced above the PL84-99 standard, and significantly increased flows in order to recover habitat and fish stocks, while avoiding the huge infrastructure costs of tunnels under the Delta. It will also provide increased self-reliance for south-of-Delta water users through inter-regional water transfers and south of Delta groundwater storage. The reinforced levees will provide increased reliability of the water supplies through the Delta. And it will accomplish the legislated goals of Estuary restoration and water reliability for billions of dollars less than currently contemplated plans.

Restoration pulse flows from a California dam temporarily increase drifting invertebrate biomass concentration

Journal of Environmental Management (Elsevier) | November 9th, 2022

The decline of Pacific salmon (Oncorhynchus spp.) populations over the last few decades has stimulated major restoration efforts across the Pacific Northwest to improve t

The decline of Pacific salmon (Oncorhynchus spp.) populations over the last few decades has stimulated major restoration efforts across the Pacific Northwest to improve the status of these iconic fishes. The leading factors contributing to the decline of Pacific salmon include watershed degradation and water diversions, which result in part from widespread dam construction across the United States (Moyle, 1994). Early river restoration actions primarily focused on physical habitat alterations (e.g., in-stream habitat improvement, fish passage; Barinaga, 1996; Bernhardt et al., 2005), while more recent work has centered around restoring natural processes (Johnson et al., 2019). Since socioeconomic and political complications are typically too great for dam removal projects to be feasible, reconciliation ecology, which encourages the accommodation of both human and wildlife needs in a human-dominated landscape, can be a more effective approach to restoration (Rosenzweig, 2003; Moyle et al., 2017). Rather than the elusive goal of returning rivers to a natural flow regime, the aim can be to attain functional environmental flows to support beneficial flow-ecology relationships (Poff et al., 2017). Dams can be operated to reduce some of their detrimental effects by releasing flows that improve downstream habitat through the preservation of key hydrologic signals upon which biophysical processes and native biological communities depend (Yarnell et al., 2020). Four functional flow components were identified for Mediterranean montane streams: wet-season initiation flows, peak magnitude flows, spring recession flows, and dry-season low flows; see Yarnell et al. (2015) for a description about the importance of each key functional component. Several studies have identified the need to further assess linkages between streamflow, invertebrate prey availability, and drift-foraging dynamics for consideration in future restoration plans for juvenile salmonids (Weber et al., 2014; Naman et al., 2016; Lusardi et al., 2018). The focus of this study is to assess the impact of dam-release flows imitating one of those functional flow components, peak magnitude flows, on invertebrate drift as a food resource for juvenile salmonids.

Restoring the Heart of a Healthy Estuary: A Review of Restoration in the Sacramento–San Joaquin Delta and Suisun Marsh

Publisher not available | December 19th, 2025

The restoration of native species-dominated ecosystems is critical for improving ecosystem health and meeting policy goals in the Sacramento–San Joaquin Delta and Suisu

The restoration of native species-dominated ecosystems is critical for improving ecosystem health and meeting policy goals in the Sacramento–San Joaquin Delta and Suisun Marsh (upper San Francisco Estuary, collectively), one of the largest estuarine systems in North America. To accomplish large-scale restoration in this heavily altered system, a variety of projects, programs, and motivations inform restoration planning and implementation. Chapter 4 of the Delta Plan synthesizes restoration goals across these efforts to produce comprehensive ecosystem restoration targets of between 60,000 and 80,000 acres across seven ecosystem types by 2050, but a comprehensive review of restoration progress and planning to date is needed. To fill this gap, this paper analyzes the current state of ecosystem restoration in the upper San Francisco Estuary in the context of the Delta Plan targets. We review current scientific and management literature and implementation approaches, and synthesize acreage totals across completed, in-progress, and planned projects for four ecosystem types where substantial development of restoration in the system has occurred: tidal wetland, non-tidal wetland, riparian, and floodplain. We find that tidal wetland restoration has progressed more rapidly than other ecosystem types, motivated by mitigation requirements related to the federal Endangered Species Act. Across all ecosystem types, we identify both promising progress and clear needs for accelerated planning and implementation of restoration projects to meet Delta Plan 2050 targets, and discuss ongoing needs related to science, funding, and implementation.

Rethinking Management of the Colorado River through Lake Powell, Grand Canyon, and Lake Mead

Utah State University | November 15th, 2024

Reversal in estuarine sand supply driven by Holocene sea level rise: A model for sand transport in large structural estuaries, San Francisco Bay, California, USA

Elsevier | July 26th, 2024

Coastal sand supply is a critical component of shoreline stability in the face of modern threats to coastal zones such as sea level rise or anthropogenic sediment extract

Coastal sand supply is a critical component of shoreline stability in the face of modern threats to coastal zones such as sea level rise or anthropogenic sediment extraction. Understanding the natural and anthropogenically perturbed dynamics of coastal systems has become a pressing challenge for coastal communities, such as the San Francisco Bay area in the United Sates, a large structurally controlled estuary system where stakeholders seek to balance the extraction of coastal sand resources for economic use and ensure sufficient sand supply for sustaining natural coastal environments. Developing accurate and comprehensive models of sand inputs and transport pathways in different types of coastal systems is imperative to balancing these competing needs. While estuarine sediment transport has been well-studied in many systems globally, structurally controlled estuaries in tectonically active settings have received relatively less attention. The prevailing hypothesis for sediment transport through San Francisco Bay describes active input and transport of sand from a large integrated regional catchment, through multiple subembayments, and out to Pacific coast beaches; a model contrary to prevailing understanding of highstand estuarine sediment transport in most settings. We test this model by applying comprehensive sand provenance analysis to surface and near-surface sand deposits in and around San Francisco Bay coupled with sand residence time data from optically stimulated luminescence (OSL) dating. New provenance results include sand petrography modal abundances, bulk geochemistry, and U-Pb detrital zircon geochronology from 27 Holocene samples throughout the San Francisco Bay region. Collectively, these new results highlight marked sediment provenance and residence time differences between San Francisco Bay structural subembayments. In particular, distinct compositional differences and OSL ages exist between sand in the bayhead region of the estuary (OSL ages ca. 4 ka; Sacramento River/local provenance) and sand from the more distal bay regions and the Pacific coast (OSL ages ca. 1 ka; integrated Sierra Nevada provenance). These provenance differences better support a revised sand input and transport model with disconnected depocenters across three structurally restricted subembayments from bayhead to the Pacific coast. New data suggest that at present the bayhead region receives limited supply from the Sacramento-San Joaquin Delta drainage with subsidiary supply from local circum-bay drainages. Sand deposited in the region from the Pacific coast through the inlet (Golden Gate) and into the estuary consists of a combination of tidal winnowing and reworking of “relic” sand from lowstand periods combined with sand eroded from Pacific coast sea cliffs, and sand supply from local Coast Range drainages. These results suggest that sand is likely not transported directly to the Pacific coast from the Sacramento-San Joaquin Delta under modern conditions. Moreover, it is likely that structural constrictions between the main estuary and outer coast and between estuary subembayments cause abrupt cessation of sediment input from the main regional drainage during marine flooding, a feature likely common to large structurally controlled estuaries globally. This revised model for San Francisco Bay sand transport illustrates the need for research targeted at interpreting natural sand transport pathways in coastal systems where coarse sediment supply is a sustainability concern.

Review of 2018 Ocean Salmon Fisheries Stock Assessment and Fishery Evaluation Document for the Pacific Coast Salmon Fishery Management Plan

Pacific Fishery Management Council | February 11th, 2019