Water storage decisions will determine the distribution and persistence of imperiled river fishes

Ecological Society of America (Wiley) | December 17th, 2020

Managing the world’s freshwater supply to meet societal and environmental needs in a changing climate is one of the biggest challenges for the 21st century. Dams provid

Managing the world’s freshwater supply to meet societal and environmental needs in a changing climate is one of the biggest challenges for the 21st century. Dams provide water security; however, the allocation of dwindling water supply among reservoirs could exacerbate or ameliorate the effects of climate change on aquatic communities. Here, we show that the relative sensitivity of river thermal regimes to direct impacts of climate change and societal decisions concerning water storage vary substantially throughout a river basin. In the absence of interspecific interactions, future Colorado River temperatures would appear to benefit both endemic and nonnative fish species. However, endemic species are already declining or extirpated in locations where their ranges overlap with warmwater nonnatives and changes in water storage may lead to warming in some of the coolest portions of the river basin, facilitating further nonnative expansion. Integrating environmental considerations into ongoing water storage negotiations may lead to better resource outcomes than mitigating nonnative species impacts after the fact.

Water Surplus and Drought Management Update - Conditions as of 11/29/2022

Metropolitan Water District of Southern California (MWD) | December 13th, 2022

Water Temperature Modeling Platform Mid-Term Review

Delta Stewardship Council (Delta Council) | October 21st, 2021

Water Wasted to the Sea?

University of California, Davis (UC Davis) | July 15th, 2017

West False River Drought Salinity Barrier Final EIR

California Department of Water Resources (DWR) | November 8th, 2024

With the proposed project, a temporary drought salinity barrier would be installed in West False River up to two times over 10 years, with each installation remaining in

With the proposed project, a temporary drought salinity barrier would be installed in West False River up to two times over 10 years, with each installation remaining in place for up to 20 months over two consecutive calendar years. The barrier would be installed if a drought were to occur during the 2026–2035 period and the drought conditions indicate that a barrier in West False River would be an effective tool to preserve upstream reservoir storage for health, safety, and regulatory releases, while preventing saltwater intrusion into the central and southern portions of the Sacramento–San Joaquin Delta (Delta). The drought salinity barrier would be constructed only if DWR, in cooperation with other State and federal agencies, determines that drought conditions have reduced water storage in Northern California reservoirs to critical levels, such that projected Delta outflow would be insufficient to control increased salinity intrusion into the Delta. 

Western and Traditional Ecological Knowledge in ecocultural restoration

University of California, Davis (UC Davis) | October 1st, 2018

 The Delta Plan (DSC 2013) calls for “protecting and enhancing the unique cultural values” of California’s Sacramento–San Joaquin Delta, a 2,800-km2 (1,100 mi2)

 The Delta Plan (DSC 2013) calls for “protecting and enhancing the unique cultural values” of California’s Sacramento–San Joaquin Delta, a 2,800-km2 (1,100 mi2) region that was occupied by indigenous peoples for ~5,000 years. The legacies of Native Californians need to be included in the Delta Plan, especially Traditional Ecological Knowledge (TEK) of ways to gather, hunt, and fish for food; build shelters; prepare medicines; and perform ceremonies — along with ways to make tools, clothing, baskets, and shelters. Plants were not just collected but also tended, which involved planned burning, digging, planting, weeding, harvesting, and seed dispersal. Populations of plants that have cultural significance and unique values should be enhanced under the Delta Plan. While Western Ecological Knowledge (WEK) offers a strong foundation for restoration of species assemblages and ecosystems, TEK adds culturally-significant species to restoration targets and traditional management practices to achieve ecological resilience. We compare 11 attributes of WEK and TEK that aid ecological restoration; all are complementary or shared by these two ways of knowing. Both WEK and TEK emphasize adaptive approaches for managing natural resources, as mandated in the Delta Plan. We suggest that WEK–TEK restoration sites throughout the Delta can be linked (virtually) to honor cultural integrity and nurture a “Sense of Place” for Native Californians and others. At the same time, such a network could foster ways to achieve sustainability through the TEK ethic of reciprocity, which WEK lacks. A network of WEK–TEK sites could enhance unique cultural values while supporting passive recreation and attracting ecotourists. 

What will it take to stabilize the Colorado River?

American Association for the Advancement of Science (AAAS) | July 21st, 2022

The Colorado River supplies water to more than 40 million inhabitants in the southwestern United States and northwestern Mexico. A basin-wide water supply crisis is occur

The Colorado River supplies water to more than 40 million inhabitants in the southwestern United States and northwestern Mexico. A basin-wide water supply crisis is occurring because of decreased watershed runoff caused by a warming climate and legal and water management policies that allow systematic overuse. By the end of 2022, combined storage in Lake Powell and Lake Mead, the two largest reservoirs in the United States, will have declined from 95% full in 2000 to approximately 25% full. If this “Millennium Drought” persists, then stabilizing reservoir levels to avoid severe outcomes will require reducing water use to match diminished runoff. With a process underway to renegotiate interstate and international agreements on consumptive uses of the river, we describe a promising new management approach based on combined storage of both reservoirs, rather than just Lake Mead as currently used, to trigger consumptive use reductions to the Lower Basin and Mexico.

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.

Yolo Bypass Salmon Habitat Restoration and Fish Passage Analytical Tool Review

Delta Stewardship Council (Delta Council) | October 1st, 2017

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operat

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operations of the Central Valley Project (CVP) and State Water Project (SWP) that includes Reasonable and Prudent Alternatives (RPA) designed to alleviate jeopardy to listed species and adverse modification of critical habitat. NMFS’ RPA requires the U.S. Bureau of Reclamation (Reclamation) to increase juvenile flood plain rearing habitat and improve adult fish passage for ESA-listed salmonids and sturgeon. The BiOp requires seventy-three (73) habitat restoration actions, five of which are specific to the Yolo Bypass. The California Department of Water Resources (DWR) and Reclamation have developed project alternatives for the Draft Yolo Bypass Fish Passage and Habitat Restoration EIS/EIR focused on the following two Yolo Bypass actions, which are the subject of this review:  - Increase seasonal floodplain inundation in the lower Sacramento River Basin  - Improve fish passage throughout the Yolo Bypass Alternatives The alternatives developed to address these two actions consist of a notch in the Fremont Weir, with alternative locations and configurations (width and weir-crest elevations), designed to increase the frequency and duration of hydraulic connectivity between the main-stem Sacramento River and the Yolo Bypass and to improve fish passage. Six alternative locations / configurations for a notch were identified.

Yuba-Feather FIRO Final Viability Assessment

California Department of Water Resources (DWR) | March 14th, 2025

This Yuba-Feather Final Viability Assessment (FVA) evaluates whether improved precipitation and runoff forecasts can reduce flood risk downstream of New Bullards Bar (NBB

This Yuba-Feather Final Viability Assessment (FVA) evaluates whether improved precipitation and runoff forecasts can reduce flood risk downstream of New Bullards Bar (NBB), owned and operated by Yuba Water Agency (Yuba Water), and Lake Oroville (ORO), owned and operated by the California Department of Water Resources (DWR). These reservoirs are in the Yuba-Feather watersheds in the Sierra Nevada and eastern Sacramento Valley of Northern California (Figure ES-1 and ES-2). Each reservoirs’ flood risk reduction operations are regulated by United States Army Corps of Engineers (USACE) through Water Control Manuals (WCMs).  Reducing flood risk by making reservoir releases ahead of storms creates additional temporary flood storage space for anticipated inflows but requires confidence and skill in forecasted conditions.