2021 Emergency Drought Salinity Barrier Project Water Quality Certification

California State Water Resources Control Board (SWRCB) | May 28th, 2021

The California Department of Water Resources (DWR) is proposing to implement the 2021 Emergency Drought Salinity Barrier Project (Project). The Project consists of instal

The California Department of Water Resources (DWR) is proposing to implement the 2021 Emergency Drought Salinity Barrier Project (Project). The Project consists of installation of a temporary emergency drought salinity barrier across West False River in the Sacramento-San Joaquin Delta (Delta). The barrier will be constructed of embankment rock (riprap). The purpose of the Project is to control saltwater intrusion into the Central and south Delta and conserve water in upstream reservoirs for other uses. Pursuant to Clean Water Act section 401, the State Water Resources Control Board (State Water Board) has authority to consider whether a proposed activity involving a discharge to navigable waters complies with applicable water quality standards and other appropriate requirements of state law and to issue a water quality certification if those requirements will be met. The State Water Board concludes that, as conditioned herein, water quality certification may be issued.  During drought conditions, the release of water stored in upstream reservoirs may be insufficient to repel salinity moving upstream from San Francisco Bay. According to DWR’s analyses, without the protection of the drought salinity barrier, saltwater intrusions could render Delta water unusable for agricultural needs, reduce habitat value for aquatic species, and affect roughly 25 million Californians who rely on the export of this water for personal use. Installation of the temporary rock barrier at West False River would limit salinity intrusion into the Central and south Delta and would potentially conserve water for a variety of uses system-wide.  On May 10, 2021, California Governor Gavin Newsom issued a Proclamation of State of Emergency (May 2021 Proclamation) due to drought conditions and directed DWR, among other things, to implement plans that address potential Delta salinity issues, including installation and removal of emergency drought salinity barriers as needed. The May 2021 Proclamation mandates that such emergency barriers be designed to conserve water for use later in the year to meet state and federal Endangered Species Act requirements, preserve to the extent possible water quality in the Delta, and retain water supply for human health and safety uses. The State Water Board and the California Department of Fish and Wildlife (CDFW) are also directed to immediately consider any necessary regulatory approvals needed to install emergency drought salinity barriers. Additionally, the May 2021 Proclamation suspends Water Code section 13247, which requires state agencies to comply with water quality control plans approved by the State Water Board, and suspends the California Environmental Quality Act (CEQA) for purpose of implementing actions such as the Project.  Installation and removal of the Project will require a permit from the United States Army Corps of Engineers (USACE) pursuant to Section 404 of the Clean Water Act. DWR is seeking emergency authorization under USACE’s Regional General Permit (RGP) 8 – Emergency Repair and Protection Activities. 

2022 Annual Review of the Construction and Operation of the State Water Project

California Water Commission (CWC) | January 18th, 2023

2022 Annual Water Supply and Demand Assessment Summary Report

California Department of Water Resources (DWR) | November 22nd, 2022

This summary report contains projected water shortage information at the urban water supplier level as well as regional and statewide analyses of water supply conditions

This summary report contains projected water shortage information at the urban water supplier level as well as regional and statewide analyses of water supply conditions and is intended to inform the State Water Resources Control Board (State Water Board). Additionally, the report includes information on water shortage response actions taken by urban water suppliers as a result of their Annual Water Supply and Demand Assessments (Annual Assessments), and urban water suppliers’ compliance statistics with respect to their Annual Water Shortage Assessment Report (Annual Shortage Report) submittals. The purpose of this Annual Water Supply and Demand Assessment Summary Report (Summary Report) is to fulfill the California Water Code (CWC) §10644(c)(1)(B) requirements and it is due on or before September 30, 2022, and every year thereafter. The full text of the CWC section regarding the Department of Water Resources’ (DWR) Summary Report to the State Water Board is presented below for reference.

2022 Drought Plan Klamath Project, Oregon-California Interior Region 10, California-Great Basin

U.S. Bureau of Reclamation (USBR) | April 29th, 2022

The Klamath Project (Project) delivers water for irrigation purposes to up to approximately 230,000 acres in southern Oregon and northern California when water is availab

The Klamath Project (Project) delivers water for irrigation purposes to up to approximately 230,000 acres in southern Oregon and northern California when water is available. The Project relies upon several primary water sources to meet irrigation demands including water from Upper Klamath Lake (UKL), Clear Lake Reservoir, and Gerber Reservoir, and from the Klamath and Lost rivers. The Project’s water supplies (Project Supply or Supplies) have been impacted by the severe drought conditions currently affecting the Klamath Basin in southern Oregon and northern California. This 2022 Drought Plan describes the background for and the process of allocating the available Project Supply during the 2022 spring/summer irrigation season (April 15 through September 30, 20222), consistent with the contract priorities that exist within the Project.

2022 Drought Response Operations Plan

U.S. Bureau of Reclamation (USBR) | April 20th, 2022

21st century California drought risk linked to model fidelity of the El Niño teleconnection

Nature Portfolio (Springer Nature) | September 3rd, 2018

Greenhouse gas-induced climate change is expected to lead to negative hydrological impacts for southwestern North America, including California (CA). This includes a decr

Greenhouse gas-induced climate change is expected to lead to negative hydrological impacts for southwestern North America, including California (CA). This includes a decrease in the amount and frequency of precipitation, reductions in Sierra snow pack, and an increase in evapotranspiration, all of which imply a decline in surface water availability, and an increase in drought and stress on water resources. However, a recent study showed the importance of tropical Pacific sea surface temperature (SST) warming and an El Niño Southern Oscillation (ENSO)-like teleconnection in driving an increase in CA precipitation through the 21st century, particularly during winter (DJF). Here, we extend this prior work and show wetter (drier) CA conditions, based on several drought metrics, are associated with an El Niño (La Niña)-like SST pattern. Models that better simulate the observed ENSO-CA precipitation teleconnection also better simulate the ENSO-CA drought relationships, and yield negligible change in the risk of 21st century CA drought, primarily due to wetting during winter. Seasonally, however, CA drought risk is projected to increase during the non-winter months, particularly in the models that poorly simulate the observed teleconnection. Thus, future projections of CA drought are dependent on model fidelity of the El Niño teleconnection. As opposed to focusing on adapting to less water, models that better simulate the teleconnection imply adaptation measures focused on smoothing seasonal differences for affected agricultural, terrestrial, and aquatic systems, as well as effectively capturing enhanced winter runoff.

A 1,200-year perspective of 21st century drought in southwestern North America

National Academy of Sciences (NAS) | December 11th, 2009

A key feature of anticipated 21st century droughts in Southwest North America is the concurrence of elevated temperatures and increased aridity. Instrumental records and

A key feature of anticipated 21st century droughts in Southwest North America is the concurrence of elevated temperatures and increased aridity. Instrumental records and paleoclimatic evidence for past prolonged drought in the Southwest that coincide with elevated temperatures can be assessed to provide insights on temperature-drought relations and to develop worst-case scenarios for the future. In particular, during the medieval period, ∼AD 900–1300, the Northern Hemisphere experienced temperatures warmer than all but the most recent decades. Paleoclimatic and model data indicate increased temperatures in western North America of approximately 1 °C over the long-term mean. This was a period of extensive and persistent aridity over western North America. Paleoclimatic evidence suggests drought in the mid-12th century far exceeded the severity, duration, and extent of subsequent droughts. The driest decade of this drought was anomalously warm, though not as warm as the late 20th and early 21st centuries. The convergence of prolonged warming and arid conditions suggests the mid-12th century may serve as a conservative analogue for severe droughts that might occur in the future. The severity, extent, and persistence of the 12th century drought that occurred under natural climate variability, have important implications for water resource management. The causes of past and future drought will not be identical but warm droughts, inferred from paleoclimatic records, demonstrate the plausibility of extensive, severe droughts, provide a long-term perspective on the ongoing drought conditions in the Southwest, and suggest the need for regional sustainability planning for the future.

A global transition to flash droughts under climate change

American Association for the Advancement of Science (AAAS) | April 13th, 2023

Flash droughts have occurred frequently worldwide, with a rapid onset that challenges drought monitoring and forecasting capabilities. However, there is no consensus on w

Flash droughts have occurred frequently worldwide, with a rapid onset that challenges drought monitoring and forecasting capabilities. However, there is no consensus on whether flash droughts have become the new normal because slow droughts may also increase. In this study, we show that drought intensification rates have sped up over subseasonal time scales and that there has been a transition toward more flash droughts over 74% of the global regions identified by the Intergovernmental Panel on Climate Change Special Report on Extreme Events during the past 64 years. The transition is associated with amplified anomalies of evapotranspiration and precipitation deficit caused by anthropogenic climate change. In the future, the transition is projected to expand to most land areas, with larger increases under higher-emission scenarios. These findings underscore the urgency for adapting to faster-onset droughts in a warmer future.

A Measure of Snow: A Report Based on Case Studies of The Snow Survey and Water Supply Forecasting Program

U.S. Department of Agriculture (USDA) | November 1st, 2008

Snow depth and snow water content data have been collected and disseminated throughout the Western United States for over 100 years. Early snow survey and water s

Snow depth and snow water content data have been collected and disseminated throughout the Western United States for over 100 years. Early snow survey and water supply data were gathered through the efforts of university scientists, beginning with the work of Dr. James E. Church. In 1935, the Soil Conservation Service (SCS), now the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), established a formal cooperative Snow Survey and Water Supply Forecasting (SS-WSF) Program. The Agency was charged with responsibility for “conducting snow survey and water supply forecasts and the forecasting of irrigation water supplies.” The new Program would also develop consistent methods for measuring snow and reliable models for accurate water supply forecasting. Administered by NRCS, the SS-WSF Program has grown into a network of more than 1,200 manually-measured snow courses and over 750 automated Snowpack Telemetry (SNOTEL) weather stations in 13 Western States, including Alaska. (See map on page 4.) The SS-WSF Program provides manual snow course data collected by NRCS conservation professionals, automated SNOTEL data, and modeled water supply/streamflow volume data as well as issues streamflow forecasts for over 740 locations in the West. The data and the related reports and forecasts, are made available—in near real time for the automated SNOTEL sites—to private industry; to Federal, State, and local government entities; and to private citizens through an extensive Internet delivery system and other distribution channels. With 50-80 percent of the water supply in the West arriving in the form of snow, data on the snowpack provides critical information to decision-makers and water managers throughout the West. The basic data become even more valuable when used in concert with partner organizations to provide water supply forecasting tailored to meet end-user needs. According to researchers from multiple U.S. and international agencies, research centers, and academia, changes in the world’s climate have resulted in a loss of predictability in weather, precipitation, and water transport and accumulation patterns. It is anticipated that the value the SS-WSF Program provides to society will increase over time as climate variability increases. Recently a study was done to see who uses SS-WSF data, how the data are used, and the value of the data. Users of the data were interviewed and specific events and activities were analyzed. This publication is based on that study.

A Measure of Snow: Case Studies of the Snow Survey and Water Supply Forecasting Program

U.S. Department of Agriculture (USDA) | September 1st, 2010

Snow depth and snow water content data have been collected and disseminated throughout the W estern United States for over 100 years. Early Snow Survey and Wate

Snow depth and snow water content data have been collected and disseminated throughout the W estern United States for over 100 years. Early Snow Survey and Water Supply Forecasting data were gathered through the efforts of university scientists. In 1935, the Soil Conservation Service (SCS) was given $36,000 to establish a formal cooperative Snow Survey and Water Supply Forecasting (SSWSF) Program. The agency was charged with the responsibility for “conducting Snow Survey and Water Supply Forecast s and forecasting of irrigation water supplies.” The new program would also develop consistent methods for measuring snow and reliable models for water supply forecasting. Using a case study approach, this report assesses the various uses of data gathered and published by the SSWSF Program and estimates the value of those data in terms of both the market and non-market values of the information. Additionally, it evaluate s the relative merits of maintaining the program as a publicly funded program as opposed to privatizing the program. This study finds that the SSWSF Program is generating both market and non-market benefits to the U.S. economy and to U.S. society as a whole that are worth significantly more than the cost of the program. Should climate variability increase — as is expected by many of those interviewed in the course of completing this study, and as current climate research strongly suggests — the value of the information provided by the SSWSF Program will increase accordingly.