Water Surplus and Drought Management Update - Conditions as of 11/29/2022

Metropolitan Water District of Southern California (MWD) | December 13th, 2022

Water systems in California: Ownership, geography, and affordability

Utilities Policy (Elsevier) | August 10th, 2021

This study asks whether different types of water systems serve different types of communities and differ with respect to affordability. Using 2017 data for California we

This study asks whether different types of water systems serve different types of communities and differ with respect to affordability. Using 2017 data for California we match service area boundaries with census income data and rate structures to compare the geography, income distribution and affordability of water rates within communities served by systems of different ownership types. We find that for-profit and publicly owned systems serve communities of similar income distributions, while not-for-profit mutual water companies serve higher-income communities. Regulated privately-owned systems charge more for water while providing more low-income assistance and shutting off fewer households than publicly owned systems.

Water transfers (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

The California Water Code (CWC) defines a water transfer as a temporary or long-term change in the point of diversion, place of use, or purpose of use due to a transfer,

The California Water Code (CWC) defines a water transfer as a temporary or long-term change in the point of diversion, place of use, or purpose of use due to a transfer, sale, lease, or exchange of water or water rights. Temporary water transfers have a duration of one year or less (CWC Section 1725). Long-term water transfers have a duration of more than one year (CWC Section 1728). Transfers can be between water districts that are neighboring or across the state, provided there is a means to convey or store the water. A water transfer can be a temporary or permanent sale of water or a water right by the water right holder, a lease of the right to use water from the water right holder, or a sale or lease of a contractual right to water supply. Water transfers can also take the form of long-term contracts for the purpose of improving long-term supply reliability.

Water Transfers Brochure: Guidance and Information for Water Transfers

U.S. Bureau of Reclamation (USBR) | February 13th, 2014

The Bureau of Reclamation (Reclamation) developed the Water Transfers Brochure (Brochure) to assist water purveyors in the preparation of water transfer and Warren Act pr

The Bureau of Reclamation (Reclamation) developed the Water Transfers Brochure (Brochure) to assist water purveyors in the preparation of water transfer and Warren Act proposals and documents. It is a “work in progress” that will be refined as necessary to adapt to changing circumstances or improve its utility, this Brochure provides general guidance on communicating, preparing, and submitting a proposal, as well as presenting estimated timelines for associated requirements, actions, and approvals. This Brochure is meant to increase the efficiency of the logistical and administrative processes that Reclamation and the transfer parties control and to further the goal of timely facilitation of water transfers that require conveyance through Central Valley Project (CVP) facilities or otherwise require Reclamation approval. This Brochure provides a framework and certain details of the processes; however, dependent on the transfer or Warren Act proposal, additional coordination or steps may be necessary to facilitate approval of a proposed action. Reclamation encourages all water purveyors to work closely with their designated Reclamation representative in developing transfer, exchange, and/or Warren Act proposals.

Water Year 2021 Compound Precipitation and Temperature Extremes in California and Nevada

American Meteorological Society (AMS) | December 23rd, 2022

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October 2020–September 2021). Compared to an instrumental record that dates to 1895, low precipitation (Fig. 1a) and high temperatures (Fig. 1b) were widespread across the western United States. The intense and prevalent drought has caused water delivery shortages (U.S. Bureau of Reclamation 2021), damaged ecosystems (Wlostowski et al. 2022), and contributed to extreme wildfires (e.g., Fu et al. 2021; Gutierrez et al. 2021; Abolafia-Rosenzweig et al. 2022). California and Nevada (CA–NV) were once again at the epicenter of drought and heat in Water Year 2021 (California Department of Water Resources 2021). This was the first time since 1895 that precipitation fell below –1.5 standardized departures and temperatures exceeded 1.5 standardized departures concurrently for the two-state average (Fig. 1c). Precipitation and temperatures were individually extreme as well, as the former was the second lowest since 1895 and the latter was the second highest. We examine whether the co-occurrence of anthropogenic climate change and La Niña, two principal climate drivers during Water Year 2021, altered the risk of unprecedented compound dry and hot extremes in CA–NV during Water Year 2021. Our assessment investigates the factors related to compound extremes that lead to heightened societal impacts compared to individual extreme events (e.g., AghaKouchak et al. 2020; Zscheischler et al. 2020; W. Zhang et al. 2021).

Water Year 2023: Weather Whiplash, from Drought to Deluge

California Department of Water Resources (DWR) | October 4th, 2023

Water Year 2023 demonstrated California’s high climate variability, ending the state’s driest consecutive three-year period with one of the snowiest years of record.

Water Year 2023 demonstrated California’s high climate variability, ending the state’s driest consecutive three-year period with one of the snowiest years of record. Even though California has been experiencing a theme of aridity in the 21st century (the statewide droughts of 2007-2009, 2012-2019, and 2020-2022), Water Year 2017 was the state’s second wettest in terms of statewide precipitation. Climate change is expected to amplify naturally occurring variability in the long term, potentially result in a shorter wet season for California but one with more extreme atmospheric river storms and hence potentially greater flood damage risk.

Water, Sanitation, and Climate Change in the United States Series, Part 2

Pacific Institute | October 15th, 2024

In the United States, federal, tribal, state, and local laws and policies exist to govern the provision of water and sanitation services to communities and homes. The law

In the United States, federal, tribal, state, and local laws and policies exist to govern the provision of water and sanitation services to communities and homes. The laws are designed to ensure the protection of public health and the environment; deliver sufficient, safe water for drinking, bathing, cooking, and other household needs; and remove and treat domestic (i.e., household) waste. People without complete plumbing or safe water live within the “water access gap.” As explored in the first report in this series, climate change—from extreme temperatures to droughts, floods, extreme storms, and wildfires—is making it hard to close this gap and keep it from growing. Water and sanitation systems in frontline communities already feel the disproportionate “first and worst” impacts of climate change to these systems and to their access to water and sanitation. Laws and policies should help anticipate and plan  or the incremental and catastrophic impacts of climate change and protect those most harmed by the effects. Unfortunately, in most cases, the climate is changing faster than the law can respond, thereby leaving frontline communities’ water and sanitation systems vulnerable to damage or destruction. This is part two in the three-part Water, Sanitation, and Climate Change in the United States series. Click here for part one and here for part three.

Water/Wastewater Utilities and Extreme Climate and Weather Events: Case Studies on Community Response, Lessons Learned, Adaptation, and Planning Needs for the Future

Water Research Foundation | July 21st, 2014

This project consisted of a series of workshops that (1) examined the actions taken by water and wastewater utility practitioners who faced a recent extreme weather and c

This project consisted of a series of workshops that (1) examined the actions taken by water and wastewater utility practitioners who faced a recent extreme weather and climate-related event and documented their planning and response; (2) determined and recorded lessons learned; (3) documented and analyzed the decision process, including decision makers, organizations involved, and data needed for making decisions when faced with an extreme event; and (4) summarized communication approaches used to inform the public. The final report, published by WERF, consists of the workshop results and a series of case studies highlighting lessons learned and recommended actions. Additionally, the case studies were published separately and are available on this project page under Project Resources/Project Papers.

Waterline responses to climate forcing along the North American West Coast

Nature Portfolio (Springer Nature) | June 7th, 2025

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between l

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between large-scale climate variability and coastal morphodynamics remain underexplored beyond intensively monitored sites. This study leverages a newly developed 25-year (1997–2022) satellite-derived waterline dataset along the North American West Coast. Our results reveal distinct latitudinal patterns in seasonal waterline change, with excursions exceeding 25 m in the Pacific Northwest, decreasing to less than 10 m in Southern California and farther south. Waterline fluctuations strongly follow wave power in the Pacific Northwest (R = −0.78), northern California (R = −0.75), and Baja California (R = −0.62), while Baja California Sur aligns more with sea-level variations (R = −0.42). Interannually, waterline change exhibits latitudinal dependence: south of southern California, variability is low, with major erosion confined to strong El Niño-Southern Oscillation (ENSO) events, while northern regions show mixed responses. ENSO-driven storm track shifts modulate winter wave climate, resulting in enhanced (attenuated) erosion from southern California to Baja California Sur during El Niño (La Niña). However, further north, ENSO impacts are less consistent, reflecting a complex interplay of storm track displacement and intensification. These findings highlight the spatial complexity of ENSO-driven morphodynamics and provide a framework for assessing climate-induced coastal vulnerability.

Watershed Management (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

Watershed management is the process of creating and implementing plans, programs, projects, and activities to restore, sustain, and enhance watershed functions. These fun

Watershed management is the process of creating and implementing plans, programs, projects, and activities to restore, sustain, and enhance watershed functions. These functions provide the goods, services, and values desired by the human community that are affected by conditions within a watershed. The practice of community-based watershed management, which is practiced in hundreds of watersheds throughout the state, has evolved as an effective approach to natural resource management. These community-based efforts are carried out with the active support, assistance, and participation of several State agencies and programs. Managing at a watershed level has proven to be an appropriate organizing landscape unit for the coordination and integrated management of the numerous physical, chemical, and biological processes that make up a river basin ecosystem (Box 1). A watershed serves well as a common reference unit for the many different policies, actions, and processes that affect the system, and it also provides a basis for greater integration and collaboration among those policies and actions.