Colorado River

Californians Without Safe Water and Sanitation: California Water Plan Update 2013

California Department of Water Resources (DWR) | February 20th, 2015

This report was prepared as part of the California Water Plan Update 2013 process and is an update to the 2005 Californians without Safe Water report. It continues the d

This report was prepared as part of the California Water Plan Update 2013 process and is an update to the 2005 Californians without Safe Water report. It continues the dialogue regarding Californians without safe drinking water and/or adequate sanitation facilities and includes 14 recommendations towards ensuring that all Californians have safe drinking water and adequate sanitation facilities. The report also highlights Governor Brown’s goal of ensuring that all Californians have access to safe drinking water, as specified by his signing of Assembly Bill (AB) 685 and the release of the California Water Action Plan that includes Action 7, “Provide Safe Water for All Communities.”

CaliPopGen: A genetic and life history database for the fauna and flora of California

Nature Portfolio (Springer Nature) | July 5th, 2022

CaliPopGen is a database of population genetic data for native and naturalized eukaryotic species in California, USA. It summarizes the published literature (1985–2020)

CaliPopGen is a database of population genetic data for native and naturalized eukaryotic species in California, USA. It summarizes the published literature (1985–2020) for 5,453 unique populations with genetic data from more than 187,394 individuals and 448 species (513 species plus subspecies) across molecular markers including allozymes, RFLPs, mtDNA, microsatellites, nDNA, and SNPs. Terrestrial habitats accounted for the majority (46.4%) of the genetic data. Taxonomic groups with the greatest representation were Magnoliophyta (20.31%), Insecta (13.4%), and Actinopterygii (12.85%). CaliPopGen also reports life-history data for most included species to enable analyses of the drivers of genetic diversity across the state. The large number of populations and wide taxonomic breadth will facilitate explorations of ecological patterns and processes across the varied geography of California. CaliPopGen covers all terrestrial and marine ecoregions of California and has a greater density of species and georeferenced populations than any previously published population genetic database. It is thus uniquely suited to inform conservation management at the regional and state levels across taxonomic groups.

CASGEM Alternative Monitoring Plan Fact Sheet

California Department of Water Resources (DWR) | August 15th, 2023

Causes of the Extreme Dry Conditions over California During Early 2013

American Meteorological Society (AMS) | September 30th, 2014

The state of California experienced extreme dry conditions during early 2013. In particular, January and February received 28% and 15%, respectively, of their nor

The state of California experienced extreme dry conditions during early 2013. In particular, January and February received 28% and 15%, respectively, of their normal monthly rainfall. When January and February are combined, January/ February 2013 is ranked as the driest of the period 1895–2014. Such large precipitation deficits exerted enormous stress on water resources in an already high water-demand region. Thus, it is of practical importance to investigate the causes of this extreme climate event so as to assess its predictability. *Chapter 3, Explaining Extreme Events of 2013 from a Climate Perspective, Bull. Amer. Meteor. Soc., 95 (9)

Characterizing uncertain sea-level rise projections to support investment decisions

PLOS | February 17th, 2018

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regardi

Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea- level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments. Results highlight the highly-localized and context dependent nature of applying Robust Decision Making methods to inform investment decisions.

Civic Engagement and Water Data: How Can California Make Data Work for Decision Makers?

University of California, Berkeley (UC Berkeley) | September 1st, 2020

 Much attention is focused on water data in California, and for good reason. California is struggling to make decisions that adapt its water systems to pressures such as

 Much attention is focused on water data in California, and for good reason. California is struggling to make decisions that adapt its water systems to pressures such as climate change and population growth. Fully informed decisions are impossible without accurate and accessible data and information to support them. California already produces immense amounts of water-related data. However, agencies and stakeholders currently struggle to bring these data together to support routine decision making. Overall, we lack any systematic understanding of whether and how existing data can support the needs of decision makers. 

Climate Action Plan

Metropolitan Water District of Southern California (MWD) | May 31st, 2022

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing clim

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing climatic conditions, variable precipitation patterns, availability of water supplies, changes in consumer demands, and sea level rise will change the way Metropolitan provides its services and how it operates its regional water system. Metropolitan recognizes the potential impact of climate change to water availability and is committed to environmental stewardship to protect this valuable resource. Reducing greenhouse gas (G H G) emissions is an important step in protecting California and the region from the effects of climate change. Reducing G H G emissions from Metropolitan’s operations supports California’s overall G H G reduction goals. This Climate Action Plan (CAP) sets targets for reducing G H G emissions from Metropolitan’s operations, including conveyance, storage, treatment, and delivery of water to its 26 member water agencies. Additionally, this CAP complements Metropolitan’s existing long-range planning efforts, including the Integrated Water Resources Plan, Energy Sustainability Plan, and Capital Investment Plan. Through the implementation of this CAP, Metropolitan will strengthen its commitment to environmental sustainability, increase the resiliency of its operations, and strategically achieve G H G reduction goals. For additional details on the purpose of this CAP and Metropolitan’s history and existing operations, refer to Section 1.0, Purpose, Overview, and Environmental History and Leadership.

Climate Action Plan Phase 1 Greenhouse Gas Emissions Reduction Plan Update 2023

California Department of Water Resources (DWR) | March 22nd, 2024

DWR developed the Greenhouse Gas Emissions Reduction Plan Update 2023 (Update 2023) to review its GHG reductions since Update 2020 and to update strategies for further re

DWR developed the Greenhouse Gas Emissions Reduction Plan Update 2023 (Update 2023) to review its GHG reductions since Update 2020 and to update strategies for further reduction consistent with legislative changes, including the GHG emissions reduction targets established in SB 1020 (2022) and SB 1203 (2022). It also includes DWR’s new role in emergency energy generation. Since the 2012 Plan was adopted, California’s wholesale electricity market has also seen a significant increase in renewable resources. To reflect this change and to align with industry practice in emission reporting, Update 2023 incorporates updated emission factors to determine emissions from unspecified market resources.

Climate change is increasing the likelihood of extreme autumn wildfire conditions across California

Environmental Research Letters (IOP) | August 20th, 2020

California has experienced devastating autumn wildfires in recent years. These autumn wildfires have coincided with extreme fire weather conditions during periods of stro

California has experienced devastating autumn wildfires in recent years. These autumn wildfires have coincided with extreme fire weather conditions during periods of strong offshore winds coincident with unusually dry vegetation enabled by anomalously warm conditions and late onset of autumn precipitation. In this study, we quantify observed changes in the occurrence and magnitude of meteorological factors that enable extreme autumn wildfires in California, and use climate model simulations to ascertain whether these changes are attributable to human-caused climate change. We show that state-wide increases in autumn temperature (~1 °C) and decreases in autumn precipitation (~30%) over the past four decades have contributed to increases in aggregate fire weather indices (+20%). As a result, the observed frequency of autumn days with extreme (95th percentile) fire weather—which we show are preferentially associated with extreme autumn wildfires—has more than doubled in California since the early 1980s. We further find an increase in the climate model-estimated probability of these extreme autumn conditions since ~1950, including a long-term trend toward increased same-season co-occurrence of extreme fire weather conditions in northern and southern California. Our climate model analyses suggest that continued climate change will further amplify the number of days with extreme fire weather by the end of this century, though a pathway consistent with the UN Paris commitments would substantially curb that increase. Given the acute societal impacts of extreme autumn wildfires in recent years, our findings have critical relevance for ongoing efforts to manage wildfire risks in California and other regions.

Climate change is increasing the risk of a California megaflood

American Association for the Advancement of Science (AAAS) | August 12th, 2022

Despite the recent prevalence of severe drought, California faces a broadly underappreciated risk of severe floods. Here, we investigate the physical characteristics of

Despite the recent prevalence of severe drought, California faces a broadly underappreciated risk of severe floods. Here, we investigate the physical characteristics of “plausible worst case scenario” extreme storm sequences capable of giving rise to “megaflood” conditions using a combination of climate model data and high-resolution weather modeling. Using the data from the Community Earth System Model Large Ensemble, we find that climate change has already doubled the likelihood of an event capable of producing catastrophic flooding, but larger future increases are likely due to continued warming. We further find that runoff in the future extreme storm scenario is 200 to 400% greater than historical values in the Sierra Nevada because of increased precipitation rates and decreased snow fraction. These findings have direct implications for flood and emergency management, as well as broader implications for hazard mitigation and climate adaptation activities.