Water Reliability in the West - 2021 SECURE Water Act Report

U.S. Bureau of Reclamation (USBR) | January 4th, 2021

The Bureau of Reclamation (Reclamation) is the largest wholesaler of water in the country. Reclamation delivers water for municipal, agricultural, tribal, and environment

The Bureau of Reclamation (Reclamation) is the largest wholesaler of water in the country. Reclamation delivers water for municipal, agricultural, tribal, and environmental water uses, including providing one out of five farmers in the Western United States (West) with irrigation water for 10 million acres of farmland that produce 60 percent of the Nation’s vegetables and 25 percent of its fruits and nuts. The Omnibus Public Land Management Act of 2009 (Public Law 111-11), Subtitle F of Title IX of the Act (Science and Engineering to Comprehensively Understand and Responsibly Enhance [SECURE] Water Act) recognizes that changes to temperature, precipitation (rainfall and snowfall), and the timing and quantity of snowpack and runoff pose a significant challenge to the protection and use of water resources. Every 5 years, Reclamation submits a report to Congress under the SECURE Water Act that analyzes projected risks to water supplies in the West using the best available science and highlights collaborative efforts to mitigate those risks. This Water Reliability in the West - 2021 SECURE Water Act Report (2021 Report) provides a West-wide assessment of expected changes to water supplies, uses, and demands; highlights progress; and describes actions taken to increase water supply reliability since the 2016 SECURE Water Act Report. Reclamation has a broad range of programs and projects that help increase the reliability of water and power deliveries. Our activities include science and research, planning, infrastructure sustainability, efficient hydropower production, and on-the-ground actions to increase reliable water supplies to meet water demands. These activities are undertaken in collaboration with our customers, stakeholders, and partners. In the West, competing demands for water for farms, cities, Tribes, the environment, recreation, hydropower, and other uses can lead to conflict. Conflict escalates particularly during droughts, which are expected to be more frequent and severe with climate change. Fostering strong relationships is essential to carry out Reclamation’s everyday operations, conduct long-term planning efforts, and avoid unnecessary conflicts. Reclamation operators and planners rely on information about precipitation, snowpack, streamflow, temperatures, water demands, and groundwater to make informed decisions. Reclamation’s 2021 West-Wide Climate and Hydrology Assessment (2021 Assessment) builds on our 2011 and 2016 West-wide assessments of future temperature and precipitation change by using several complementary approaches, including analyses based in paleohydrology derived from tree rings (dendochronology) that help answer this question: “If droughts in the distant past were to occur today, how would water systems perform?” With our Federal, State, Tribal, and local partners, we address challenges resulting from climate change and shifting demographics. We use a multi-faceted approach to support reliable water and hydropower deliveries; to help maintain healthy ecosystems; to protect federally-listed fish, wildlife, and plants, as well as designated critical habitat; and to manage risks (e.g., droughts, floods, and fires). Implementing the SECURE Water Act has served as a catalyst for collaboration and innovation, improving our understanding of climate change impacts to water resources and our ability to address those impacts.

Water resource utilization and future supply–demand scenarios in energy cities of semi-arid regions

Nature Portfolio (Springer Nature) | February 11th, 2025

Analyzing the characteristics of water resource utilization and forecasting future supply–demand dynamics are of great practical significance for water resource plannin

Analyzing the characteristics of water resource utilization and forecasting future supply–demand dynamics are of great practical significance for water resource planning and allocation. This study focuses on the water supply–demand challenges in energy cities located in semi-arid regions, using Qingyang City as a case study. The future water demand of various sectors was simulated and projected, and the supply–demand balance under different socioeconomic and climate scenarios was analyzed using the Shared Socioeconomic Pathways framework combined with climate model data. This research addresses the gap in the existing literature concerning the analysis of water supply–demand structures in energy cities under climate change and provides scientific support for regional sustainable development. The results show that: (1) Over the past 20 years, water supply and utilization in Qingyang City have exhibited significant growth trends, with agricultural water use continuously increasing, industrial water use fluctuating, domestic water use remaining stable, and ecological water use growing significantly; (2) From 2024 to 2035, the water demand of various sectors is projected to change substantially, with agricultural and ecological water use being highly sensitive to scenario configurations; (3) Under high economic growth scenarios, Qingyang City is likely to face severe water shortages.

Water Risk Hotspots for Agriculture: The Case of the Southwest United States

Organisation for Economic Co-operation and Development (OECD) | July 14th, 2016

The Southwest United States – defined here as Arizona, California, Colorado, Nevada, New Mexico, and Utah – is a rapidly growing region that faces major water challe

The Southwest United States – defined here as Arizona, California, Colorado, Nevada, New Mexico, and Utah – is a rapidly growing region that faces major water challenges. It has the fastest growing population and one of the most economically productive regions of the United States. It is also the most arid region and is prone to long-term droughts. These dry conditions, combined with a water allocation system based on prior appropriation — whereby the “first in time” is the “first in line” to access water — generate tension between stable or declining sectors of the economy that hold the majority of the rights to water and the fast-growing sectors of the economy that have more limited water rights. The Southwest provides a case study of the challenges posed by limited water availability and some of the successful methods used to bridge the gap between water supply and demand.

Water Supply Forecasting

U.S. Department of Agriculture (USDA) | March 9th, 2011

Chapter 7: Part 622 Snow Survey and Water Supply Forecasting from the National Engineering Handbook The U.S. Department of Agriculture (USDA) Natural Resources Conser

Chapter 7: Part 622 Snow Survey and Water Supply Forecasting from the National Engineering Handbook The U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Snow Survey and Water Supply Forecasting Program issues water supply forecasts for hundreds of points in the Western United States. The primary forecast product is a seasonal volume for a specified period of months (e.g., April–July). These forecasts are issued near the first of the month between January and June. Mid-month updates are also issued for selected forecast points. In addition, daily guidance forecasts are issued for a subset of forecast points using an automated procedure. This chapter describes the essential features of water supply forecasting as practiced in the NRCS. The topics are presented in a roughly chronological sequence of activities, from forecasting point establishment, to data gathering, to model development, to operations, and finally to verification. Citations of foundational professional literature and NRCS technical notes are given to provide sources of details on mathematical procedures and other technical information not explicitly described in this chapter.

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

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

Water Transfers in Water Resource Systems

American Society of Civil Engineers (ASCE) | March 1st, 1995

Water transfers are a common component of many regional water systems and are being increasingly considered for meeting growing water demands and for managing the impacts

Water transfers are a common component of many regional water systems and are being increasingly considered for meeting growing water demands and for managing the impacts of drought.  Water transfers can take many forms and can serve a number of different purposes in the planning and operation of water resource systems. However, to be successful, water transfers must be carefully integrated with traditional water supply augmentation and demand management measures.  This integration requires increased cooperation among different water use sectors and resolution of numerous technical and institutional issues, including impacts to third parties.  This paper identifies the many forms that water transfers can take, some of the benefits they can generate, and the difficulties and constraints which must be overcome in their implementation.

Water Year 2017: What a Difference a Year Makes

California Department of Water Resources (DWR) | October 2nd, 2017

Water year 2017 (October 1, 2016 to September 30, 2017) dramatically illustrated the variability in California’s annual precipitation, ending the state’s 5-year droug

Water year 2017 (October 1, 2016 to September 30, 2017) dramatically illustrated the variability in California’s annual precipitation, ending the state’s 5-year drought and coming in at second place for statewide runoff, behind the wettest year of 1983. Virtually all of the state experienced at least average precipitation, and key Sierra Nevada watersheds were much above average. Governor Brown lifted the proclamation of statewide drought emergency he issued in 2014, although the state-declared emergency remained in selected central California counties experiencing lingering drought impacts. Prior to 2017, California had experienced a decade of largely dry conditions. Eight of the ten preceding water years were dry, and the water years of 2012-15 set a record for the driest consecutive four-year period of statewide precipitation.

Water Year 2018 Hydrology

Delta Stewardship Council (Delta Council) | November 26th, 2018

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.