The Bureau of Reclamation has released a summary report assessing climate change impacts to water uses in the western U.S.: the Water Reliability in the West – 2021 SECURE Water Act Report. This report discusses changes and innovative actions across the eight basins identified in the SECURE Water Act.
The report describes Reclamation’s collaborative actions to increase water and power delivery reliability since the 2016 SECURE Water Act Report, including science and research; planning; infrastructure sustainability; efficient hydropower production; and on-the-ground activities to meet irrigation needs and water needed for municipalities, power, tribes and the environment.
“Our water supply and delivery systems are impacted by changing hydrologic conditions, competing demands and demographics,” Commissioner Brenda Burman said. “Reclamation is using the best-available science to carry out its mission while also collaborating with its water and power customers, states and local agencies and tribes to address critical western water management issues.”
Temperatures are expected to increase in all eight basins, while precipitation changes are variable. With warmer temperatures, more precipitation will fall as rain and snow will melt sooner, leading to snowpack declines into the future, which will impact streamflow timing. These key findings on future climate and hydrology are consistent with the conclusions of the 2016 report.
Paleohydrology – which shows how water supply has varied over past centuries using tree-ring reconstruction and other methods — has been added to help inform the 2021 report. Using this information, Reclamation can better assess whether distant droughts, going back several hundreds of years, were more similar to or greater than observed droughts in the past century, providing an extended history to understand future risks.
Also new is a West-wide drought analysis. Using the paleohydrology records, Reclamation and its study partners evaluated dry and wet period characteristics and analyzed chances of shifting between wet and dry patterns. These analyses will provide a framework for drought planning and help managers develop water management alternatives in time to take action.
Reclamation is collaborating with its customers, stakeholders and other partners to develop mitigation strategies to increased risks of drought and changes to precipitation, runoff and increased temperatures. These strategies include:
- Supporting reliable water deliveries through construction activities, water management improvements, diversifying supplies through water reuse and ground and surface water conjunctive use.
- Improving hydropower generation capability, flexibility and reliability through advanced decision support tools to maximize the amount of power produced with available water supplies and new technologies to keep hydropower plants operating.
- Maintaining healthy ecosystems and protecting federally listed fish, wildlife, plants and designated critical habitat affected by Reclamation facilities through a range of programs and activities.
- Addressing drought risks by proactively building resilience as the severity, duration and frequency of drought increases.
Reclamation is a federal agency under the U.S. Department of the Interior and is the largest wholesale water supplier and second largest producer of hydroelectric power in the U.S.