Sacramento River

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 Severe Drought Has Only Marginal Impacts on Food Prices

University of California Giannini Foundation of Agricultural Economics | May 14th, 2015

The extreme drought that has gripped California over the past several years is causing onerous adjustments in the natural and human environments. Agriculture, which uses

The extreme drought that has gripped California over the past several years is causing onerous adjustments in the natural and human environments. Agriculture, which uses much of the state’s water, is at the center of many of these arduous responses. The 2015 impacts of the continuing drought are still underway, but in this special Agriculture and Resource Economics Update issue, we project responses and consequences within agriculture and more broadly. In this issue, Hanak and Mount put this drought in the context of California’s history and put agriculture in the context of water institutions, management, and distribution throughout the state. Next, Medellin-Azuara and co-authors develop detailed, and albeit preliminary, assessments of 2015 irrigation water distribution. They estimate a cut to agriculture of about 8.8 million acre-feet, or about 30% of what might be available in a normal year. (This number may be an underestimate given recent events.) During droughts, farms increase groundwater pumping. The authors estimate that farmers and ranchers will replace about 6.2 million acre-feet of lost surface water deliveries with costly increases in groundwater pumping, where possible in 2015. Another painful response to drought is to leave land idle. The authors estimate about 564,000 more acres, mostly field crop land in the Central Valley (including irrigated pastures), will be idled in 2015. This too may be an underestimate. USDA reported on June 30, that 2015 California acreage of “principal crops,” (defined as field crops such as hay, grains, oilseeds, cotton and potatoes) is about 900,000 acres below the 2013 total of about four million acres. Over this period, tree nut and tomato acreage increased by about 180,000 acres. So, even accounting for the steady shift to tree nuts and some other higher revenue per acre (and per acre-foot) crops, there is a strong indication of severely accelerated reductions in field crop acreage in California. The economic toll of the drought is fewer jobs and smaller value of output and economic contribution that would have otherwise occurred. Based on 564,000 idled acres, Howitt et al. estimates farm revenue losses of $1.8 billion, economy-wide revenue losses of $2.7 billion, and 18,600 fewer jobs due to the agricultural drought. That these economic impacts are not even larger is a testament to the extraordinary efforts and innovations by farmers, and others in California agriculture. Idling land, shifting water across crops, and using each acre-foot more economically all have led to smaller losses of revenue and jobs, and only very small price increases for consumers.

California’s Stream Flow Monitoring System Is Essential for Water Decision Making

University of California, Berkeley (UC Berkeley) | April 1st, 2018

With California’s drought risk, flood risk, and demand for water all increasing, effective monitoring is more important than ever to water decision making. Str

With California’s drought risk, flood risk, and demand for water all increasing, effective monitoring is more important than ever to water decision making. Stream gages monitor the most basic vital sign of California’s waterways—stream flow.1 Stream flow data support day-to-day decisions about how to manage water and operate water infrastructure. In turn, those decisions have important implications for flood control and the water supplies upon which residential, industrial, agricultural, and environmental water users depend. Stream flow information also provides technical insights into basin hydrology, and those insights aid long-term water planning. As pressures on the state’s water systems intensify, the need for accurate and timely stream flow information will continue to grow. Opportunities for better water management created by groundbreaking legislation such as the Sustainable Groundwater Management Act (SGMA), the Open and Transparent Water Data Act, and Proposition 1 will be severely limited without an effective network of continuous stream gaging.

California’s Water Market, By the Numbers, Update 2021

Public Policy Institute of California (PPIC) | December 31st, 2021

This appendix serves as an update to the data on surface water trading and groundwater banking provided in the PPIC publication, California’s Water Market, By the Numb

This appendix serves as an update to the data on surface water trading and groundwater banking provided in the PPIC publication, California’s Water Market, By the Numbers: Update 2012 (Hanak and Stryjewski 2012). In each section, we describe data sources and methods and present summary statistics.

California’s Water: Protecting Headwaters

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

Mountainous regions provide most of the state’s water supply. But major problems loom— from a growing risk of wildfires to a shrinking snowpack. This brief outlin

Mountainous regions provide most of the state’s water supply. But major problems loom— from a growing risk of wildfires to a shrinking snowpack. This brief outlines ways California and the federal government—the largest landowner in headwater areas—could address critical problems in these areas. This publication is part of a briefing kit that summarizes a dozen of the state’s most pressing water management issues.

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.

CalSim 3 Results for 2070 Climate Change and Sea Level Projections and Sensitivity Analysis

California Department of Water Resources (DWR) | January 17th, 2024

This Technical Memorandum (TM) summarizes the key findings from a sensitivity analysis performed to analyze operations of the proposed Delta Conveyance Project (DCP) and

This Technical Memorandum (TM) summarizes the key findings from a sensitivity analysis performed to analyze operations of the proposed Delta Conveyance Project (DCP) and potential project water supply benefits under a range of potential scenarios for 2070 conditions. These scenarios consider climate change, sea level rise (SLR), and various water management responses. In addition, this sensitivity analysis also helps to identify whether proposed project operations and potential project impacts detailed in the Final DCP Environmental Impact Report (EIR) would remain similar or differ under a different climate change and SLR scenario under 2070 conditions, a more distant future.

Carbon Sequestration and Subsidence Reversal in the Sacramento–San Joaquin Delta and Suisun Bay: Management Opportunities for Climate Mitigation and Adaptation

University of California, Davis (UC Davis) | August 28th, 2023