North Lahontan

Groundwater Quality Data for the Tahoe–Martis Study Unit, 2007: Results from the California GAMA Program

U.S. Geological Survey (USGS) | November 30th, 2007

Groundwater quality in the approximately 460-square-mile Tahoe–Martis study unit was investigated in June through September 2007 as part of the Priority Basin Project o

Groundwater quality in the approximately 460-square-mile Tahoe–Martis study unit was investigated in June through September 2007 as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB).

Groundwater quality in the Cascade Range and Modoc Plateau, California

U.S. Geological Survey (USGS) | April 1st, 2015

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monito

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Cascade Range and Modoc Plateau area constitutes one of the study units being evaluated.

Groundwater Sustainability Plan Implementation: A Guide to Annual Reports, Periodic Evaluations, and Plan Amendments

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

This document provides guidance to groundwater sustainability agencies (GSAs) preparing Annual Reports, Periodic Evaluations, and Groundwater Sustainability Plan (GSP or

This document provides guidance to groundwater sustainability agencies (GSAs) preparing Annual Reports, Periodic Evaluations, and Groundwater Sustainability Plan (GSP or Plan) Amendments under the Sustainable Groundwater Management Act (SGMA or Act) and the GSP Regulations. This guidance document does not create any new requirements or obligations for GSAs but is intended to clarify the necessary content of the documents already required by SGMA and the GSP Regulations.

Groundwater-dependent ecosystem map exposes global dryland protection needs

Nature Portfolio (Springer Nature) | July 17th, 2024

Guidelines for the Small Community Drought Relief Program

California Department of Water Resources (DWR) | September 20th, 2022

Hexavalent Chromium Maximum Contaminant Level (MCL) Standardized Regulatory Impact Assessment (SRIA)

California State Water Resources Control Board (SWRCB) | May 4th, 2023

The Division of Drinking Water (DDW) of the State Water Resources Control Board (State Water Board) is responsible for adopting drinking water standards. Primary drinking

The Division of Drinking Water (DDW) of the State Water Resources Control Board (State Water Board) is responsible for adopting drinking water standards. Primary drinking water standards, as defined in section 116275 of the California Safe Drinking Water Act (Health & Safety Code (HSC), div. 104, pt. 12, ch. 4, section 116270 et seq.), must be set in accordance with the requirements of HSC 116365. The purpose of the proposed regulation addressed in this Standardized Regulatory Impact Assessment (SRIA) is to adopt a primary drinking water standard for hexavalent chromium in drinking water consisting of a maximum contaminant level (MCL) and pertinent monitoring and reporting requirements. Consistent with title 1 of the California Code of Regulations (CCR), section 2003(a), the economic impact method used for the assessment was the Regional Input-Output Modeling System (RIMS II) developed by the U.S. Bureau of Economic Analysis (BEA).

Highlights Central Valley Flood Protection Plan 2022 Update

California Department of Water Resources (DWR) | January 23rd, 2023

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on Decemb

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on December 27th, 2022, a series of atmospheric rivers began to impact California. This succession of atmospheric rivers resulted in 34 trillion gallons of water falling across California in 24 days, and 21 forecast points in the Central Valley reaching flood or monitor stage. Governor Gavin Newsom declared a state of emergency on January 4th, 2023; federal emergency and disaster declarations followed soon thereafter. These events underscore the importance of the CVFPP as the State’s strategic blueprint for investment in flood risk reduction in the Central Valley, especially in an era of whiplash weather—from drought to flooding— driven by the impacts of climate change.

Human emissions drive recent trends in North Pacific climate variations

Nature Portfolio (Springer Nature) | August 14th, 2025

Click here for a plain language discussion of the article by co-authors Pedro N. DiNezio and Timothy M. Shanahan

Click here for a plain language discussion of the article by co-authors Pedro N. DiNezio and Timothy M. Shanahan

Human-wildlife conflict is amplified during periods of drought

American Association for the Advancement of Science (AAAS) | November 12th, 2025

Climate change–induced alterations to human-wildlife interactions are recognized to pose a fundamental challenge for global conservation initiatives. However, the exten

Climate change–induced alterations to human-wildlife interactions are recognized to pose a fundamental challenge for global conservation initiatives. However, the extent to which specific climatic disturbances influence dynamics of human-wildlife conflict across different taxonomic groups remains poorly understood. Here, we leverage an extensive dataset of community-derived human-wildlife conflict incidents to examine the influence of drought, represented by the variation in summed precipitation over the prior 12 months, on conflict reporting. We show that prolonged decreases in precipitation are associated with increased overall conflict occurrences across taxa and are significantly associated with increased conflict with carnivore species in particular. A future with increasingly severe and frequent droughts could lead to resource scarcity that not only causes conflict between humans but also between humans and the natural world around them.

Hydroclimate Report Water Year 2018

California Department of Water Resources (DWR) | March 31st, 2020

Water year (WY) 2018 whipsawed from dry to wet and added high heat for the summer. The WY ended with 82 percent of average precipitation in the Northern Sierra and 20 per

Water year (WY) 2018 whipsawed from dry to wet and added high heat for the summer. The WY ended with 82 percent of average precipitation in the Northern Sierra and 20 percent below average April-July streamflow in the Sacramento River and 19 percent below average for the San Joaquin River. Peak statewide snowpack was only 60 percent of average. While precipitation and stream flow were below average, the big story of the 2018 WY were record temperatures that lead to several unprecedented and deadly wildfires in the state.