North Coast

Assumptions and Estimates for California Water Plan Update 2023 (Draft)

California Department of Water Resources (DWR) | October 14th, 2022

The draft Assumptions and Estimates for California Water Plan Update 2023 (draft A&E Report) describes key assumptions and estimates, data and data sources; improvements

The draft Assumptions and Estimates for California Water Plan Update 2023 (draft A&E Report) describes key assumptions and estimates, data and data sources; improvements to analytical tools, methods, and approaches; and the supporting documents and companion State plans being used to prepare California Water Plan Update 2023 (Update 2023), State government’s strategic plan for managing and developing water resources for sustainability and resilience. The draft A&E Report cites the statutory requirements for the California Water Plan (Water Plan), key legislative and policy drivers, assumptions, and estimates related to water data portfolios, future scenarios, water accounting, watershed resilience planning, and equity in water resource management. Also discussed are resource management strategies, the alignment of integrated watershed programs and plans, and integration and alignment of State plans.

Atmospheric river activity during the late Holocene exceeds modern range of variability in California

Nature Portfolio (Springer Nature) | April 25th, 2024

Atmospheric rivers are associated with some of the largest flood-producing precipitation events in western North America, particularly California. Insight into past extre

Atmospheric rivers are associated with some of the largest flood-producing precipitation events in western North America, particularly California. Insight into past extreme precipitation can be reconstructed from sedimentary archives on millennial timescales. Here we document atmospheric river activity near Leonard Lake, California, over 3,200 years, using a key metric of atmospheric river intensity, that is silicon/aluminum enriched layers that are highly correlated with modern records of integrated vapor transport. The late twentieth century had the highest median integrated vapor transport since the onset of the Medieval Climate Anomaly, with integrated vapor transport increasing during the Little Ice Age. The reconstruction suggests California has experienced pluvial episodes that exceeded any in the meteorologic instrumental era, with the largest episodes occurring two and three millennia ago. These results provide critical data to help avoid underestimation of potential risks and aid future planning scenarios.

Atmospheric Rivers Impacting Northern California Exhibit a Quasi-Decadal Frequency

American Geophysical Union (AGU) | July 26th, 2021

In Northern California, much of the precipitation and surface water comes from atmospheric rivers–corridors of moisture transport from the tropics. The frequency of atm

In Northern California, much of the precipitation and surface water comes from atmospheric rivers–corridors of moisture transport from the tropics. The frequency of atmospheric rivers is cyclical, with periods of water surplus and deficit in the region that repeat every 10–17 years. While many social and political factors influence water resource distribution, understanding the climate factors that regulate water availability is important for managing water in the future. Using data from observations and modeling experiments, the pronounced wet/dry cycle in this area of the Western United States is mainly attributed to regular fluctuations in sea surface temperatures in the tropical Pacific Ocean. This analysis provides a potential source of predictability for atmospheric river frequency, and thus water availability, years before a winter season.

Beaches

Scientific American | August 1st, 1960

Beaches are natural playgrounds partly under the sun and partly under the sea where people can swim and surfboard, sun themselves and study other people. This human a

Beaches are natural playgrounds partly under the sun and partly under the sea where people can swim and surfboard, sun themselves and study other people. This human activity tends to obscure the fact that the beach itself is constantly in motion, quietly changing its configuration and restlessly shifting its position, grain by grain, until huge masses of sand have been moved. On a small scale and in a matter of hours the sand castles disappear and the footprints are erased; on a large scale, after days and months, the height of the sand around the rocks changes, the waves break in new places and the beach becomes broader or narrower. Indeed, over a period of years large quantities of sand may arrive or depart, posing complex problems of conservation for the people who want to enjoy the beach. This dynamic quality was incorporated by the late Columbia University physiographer Douglas W. Johnson into a definition: "A beach is a deposit of material which is in transit either alongshore or off-and-on shore." Thus three elements make a beach: a quantity of rocky material, a shore-line area in which it moves and a supply of energy to move it.

Beneath the Surface: Why Reservoirs Won't Solve California's Water Woes

Center for Biological Diversity (CBD) | November 19th, 2024

Water storage and conveyance have fundamentally shaped modern California. The vast agricultural industry, as well as globally important cities like Los Angeles, were made

Water storage and conveyance have fundamentally shaped modern California. The vast agricultural industry, as well as globally important cities like Los Angeles, were made possible by storing and moving water around the state. Reservoirs are one of the primary components of California’s water storage system. There are nearly 1,500 surface storage reservoirs throughout the state, which together can store a year’s supply of water for farms and cities. But reservoirs come with high costs. They destroy and degrade habitats and alter flows in rivers and streams, harming native fish and wildlife. They emit significant amounts of greenhouse gases, worsening climate change. They cost taxpayers billions of dollars to build and maintain. And as the climate continues to warm, reservoirs will become less efficient, losing more and more of the water they hold to evaporation.  This report examines reservoirs’ environmental harms and explains why new reservoirs are not the solution to our 21st century water problems. 

Benefit Accounting of Nature-Based Solutions for Watersheds Landscape Assessment

United Nations (UN) | August 3rd, 2020

This landscape assessment is the outcome of Phase 1 of a tri-phased project and was designed to inform the path forward for engaging the private sector to invest in natu

This landscape assessment is the outcome of Phase 1 of a tri-phased project and was designed to inform the path forward for engaging the private sector to invest in nature-based solutions (NBS). A literature review was undertaken to understand the contemporary thinking around NBS and identify key opportunities and challenges faced by decision makers, practitioners and researchers. Interviews conducted with representatives of businesses, civil society and academia who have already implemented NBS projects or are looking to do so yielded qualitative responses to complement or contrast with the findings from the literature review.

Best Management Practices of the Sustainable Management of Groundwater: Land Subsidence (Draft)

California Department of Water Resources (DWR) | July 23rd, 2025

For almost a century, parts of California have been gradually sinking, impacting critical infrastructure and the communities who rely on it. Recognizing this challenge, t

For almost a century, parts of California have been gradually sinking, impacting critical infrastructure and the communities who rely on it. Recognizing this challenge, the Department of Water Resources has released a draft Best Management Practices document for public comment that will help local water agencies address this growing concern and support groundwater reliant communities. Click here for the full DWR press release.

Bioanalytical and chemical-specific screening of contaminants of concern in three California (USA) watersheds

Heliyon (Elsevier) | May 5th, 2022

To broaden the scope of contaminants monitored in human-impacted riverine systems, water, sediment, and treated wastewater effluent were analyzed using receptor-based cel

To broaden the scope of contaminants monitored in human-impacted riverine systems, water, sediment, and treated wastewater effluent were analyzed using receptor-based cell assays that provide an integrated response to chemicals based on their mode of biological activity. Samples were collected from three California (USA) watersheds with varying degrees of urbanization and discharge from municipal wastewater treatment plants (WWTPs). To complement cell assay results, samples were also analyzed for a suite of contaminants of emerging concern (CECs) using gas and liquid chromatography-mass spectrometry (GC- and LC-MS/MS). For most water and sediment samples, bioassay equivalent concentrations for estrogen and glucocorticoid receptor assays (ER- and GR-BEQs, respectively) were near or below reporting limits. Measured CEC concentrations compared to monitoring trigger values established by a science advisory panel indicated minimal to moderate concern in water but suggested that select pesticides (pyrethroids and fipronil) had accumulated to levels of greater concern in river sediments. Integrating robust, standardized bioanalytical tools such as the ER and GR assays utilized in this study into existing chemical-specific monitoring and assessment efforts will enhance future CEC monitoring efforts in impacted riverine systems and coastal watersheds.

Biological sensitivities to high-resolution climate change projections in the California current marine ecosystem

Wiley | July 28th, 2022

Building water resilience in the face of cascading wildfire risks

American Association for the Advancement of Science (AAAS) | September 15th, 2023