California’s Groundwater Conditions Semi-Annual Update: October 2022

California Department of Water Resources (DWR) | October 15th, 2022

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Wat

This report is a semi-annual update of the annual Groundwater Conditions Report published in March 2022 and part of DWR’s California’s Groundwater (Bulletin 118). Water Year 2022 groundwater data used in this report includes data received electronically by DWR as of August 31, 2022.

California’s Groundwater Conditions: Semi-Annual Update, October 2023, Fall Bulletin 118 Information Update

California Department of Water Resources (DWR) | October 12th, 2023

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquife

This semi-annual report presents data received by DWR as of August 31, 2023, and partially reflects the impacts of recent storms, flooding, and natural and managed aquifer recharge. However, it should be noted that groundwater response is a slow process and takes months to years to fully respond to changes in surface water conditions.

California’s Groundwater: Bulletin 118 — Update 2025 Highlights

California Department of Water Resources (DWR) | October 20th, 2025

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) serves as the most up-to-date and comprehensive compendium of statewide data and information

California’s Groundwater: Bulletin 118 — Update 2025 (CalGW Update 2025) serves as the most up-to-date and comprehensive compendium of statewide data and information on the occurrence, nature, uses, management, climate change vulnerability, monitoring, and conditions of California’s groundwater resources. Building on the legacy of Bulletin 118 and past California Water Plans, CalGW Update 2025 synthesizes recent data — available up to December 2023 — and closes key knowledge gaps to inform more effective statewide groundwater planning and decision-making.  CalGW Update 2025 consists of this Highlights document and a detailed statewide report, supported by a series of appendices. 

California’s Water: The Colorado River

Public Policy Institute of California (PPIC) | October 1st, 2016

The Colorado River—a major water source for Southern California’s cities and farms—is shared among seven states and Mexico. Water use now outstrips supply. The

The Colorado River—a major water source for Southern California’s cities and farms—is shared among seven states and Mexico. Water use now outstrips supply. The environmental impacts of water use in this basin pose special challenges. This brief describes adaptation strategies so that the river can continue to provide essential benefits to the region. This publication is part of a briefing kit that summarizes a dozen of the state’s most pressing water management issues.

California’s Water: Water for Farms

Public Policy Institute of California (PPIC) | October 1st, 2016

California is the nation’s largest farm state and a global market leader. Farms have steadily improved productivity per unit of water used, but the latest drought h

California is the nation’s largest farm state and a global market leader. Farms have steadily improved productivity per unit of water used, but the latest drought has exposed agriculture’s growing vulnerability to water shortages. This brief describes a number of opportunities to strengthen agricultural water management for the long term. This publication is part of a briefing kit that summarizes a dozen of the state’s most pressing water management issues.

Can water reuse save the Colorado?

University of California, Los Angeles (UCLA) | April 2nd, 2025

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnersh

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnership with Natural Resources Defense Council, has investigated water recycling progress and policy development across the seven states in the basin.

Central Valley Project: Water Supply and Yield Study

U.S. Bureau of Reclamation (USBR) | March 12th, 2008

Hydrologic conditions in California vary greatly from year to year, season to  season, and place to place.  Wet years bring the threat of floods, and drought years put

Hydrologic conditions in California vary greatly from year to year, season to  season, and place to place.  Wet years bring the threat of floods, and drought years put pressure on available water supplies. The majority of the state’s precipitation occurs in the northern third of the state during the winter, while much of the water is used in the central and southern portions  of the state during the spring and summer. Because of this, meeting California’s water demands is complicated by the logistics of moving water from its source to its place of use, which may be over hundreds of miles. The availability of storage and conveyance facilities may limit California’s ability to deliver water to the right place at the right time. The purpose of this Water Supply and Yield (WSAY) Study is to identify the following: 1. Opportunities for new firm yield and water supply improvements for CVP water service contractors (entities with contracts for the delivery of CVP water) 2. Water management actions or projects that would improve firm yield for the CVP while balancing the available supplies with existing demands 3. The financial costs of the water management actions or projects 4. Beneficiaries and beneficiaries’ willingness to pay for identified improvements

Climate and choice in the Colorado River Basin

Agricultural & Applied Economics Association (AAEA) | October 31st, 2024

Climate Change and Future Water Availability in the United States, Chapter E of U.S. Geological Survey Integrated Water Availability Assessment—2010–20

U.S. Geological Survey (USGS) | January 15th, 2025

The following are the key points of this chapter:  The steady rise in global temperature as a result of human activity is causing changes in Earth’s water cycle.

The following are the key points of this chapter:  The steady rise in global temperature as a result of human activity is causing changes in Earth’s water cycle. The amount of water stored within and moving between vapor, liquid and frozen components of the water cycle is shifting, with significant consequences for water availability. Climatic drivers underlie regional or local changes in water supply and their socioeconomic impacts. Threats to the quantity and quality of water available for humans and ecosystems in North America include increases in drought, aridification, and fire weather; heavy precipitation and flooding; cryosphere decline; rising surface-water temperatures; and saltwater intrusion in coastal areas. An understanding of how changes in the major climatic drivers impact the water cycle and the accurate simulation of impacts in hydrological models are crucial to predicting future water availability and developing adaptation strategies to ensure human and ecosystem water supplies. Companion chapters: U.S. Geological Survey Integrated Water Availability Assessment—2010–20, Chapter A Water Supply in the Conterminous United States, Alaska, Hawaii, and Puerto Rico, Water Years 2010–20, Chapter B Status of Water-Quality Conditions in the United States, 2010–20, Chapter C  Water Use Across the Conterminous United States, Water Years 2010–20, Chapter D  Integrated Water Availability in the Conterminous United States, 2010–20, Chapter F 

Climate change decisive for Asia’s snow meltwater supply

Nature Portfolio (Springer Nature) | June 24th, 2021

Streamflow in high-mountain Asia is influenced by meltwater from snow and glaciers, and determining impacts of climate change on the region’s cryosphere is essential to

Streamflow in high-mountain Asia is influenced by meltwater from snow and glaciers, and determining impacts of climate change on the region’s cryosphere is essential to understand future water supply. Past and future changes in seasonal snow are of particular interest, as specifics at the scale of the full region are largely unknown. Here we combine models with observations to show that regional snowmelt is a more important contributor to streamflow than glacier melt, that snowmelt magnitude and timing changed considerably during 1979–2019 and that future snow meltwater supply may decrease drastically. The expected changes are strongly dependent on the degree of climate change, however, and large variations exist among river basins. The projected response of snowmelt to climate change indicates that to sustain the important seasonal buffering role of the snowpacks in high-mountain Asia, it is imperative to limit future climate change.