2021 SECURE Water Act reports
Every five years, Reclamation submits a report to Congress under the SECURE Water Act analyzing projected risks to water supplies in the West using the best available science and highlighting collaborative efforts to mitigate those risks. The 2021 SECURE Water Act reporting consists of multiple documents with different levels of detail and spatial scopes; three of these are relevant to the Colorado River Basin:
The West-Wide Assessment report provides detailed estimates of changes in temperature, precipitation, snowpack, and streamflow across the West using a consistent methodology, similar to previous SECURE Water Act Reports. For the 2021 report, additional drought analyses based on tree-ring paleohydrology were performed, enabling water managers to compare the frequency and severity of droughts that occurred several hundred years ago to projections of future droughts.
- Gangopadhyay, S., and McGuire, M. (2021). West-Wide Climate and Hydrology Assessment. Technical Memorandum ENV-2021-001, Bureau of Reclamation. 423 pp. https://www.usbr.gov/climate/secure/docs/2021secure/westwidesecurereport1-2.pdf [v1.2]
The Basin Reports for each of the eight major Reclamation river basin provide in-depth discussion of changes and actions within the basin to help ensure sustainable water and power deliveries
- Reclamation. (2021b). Colorado River Basin—SECURE Water Act Section 9503(c)—Report to Congress. Bureau of Reclamation, U.S. Department of Interior. 34 pp. https://www.usbr.gov/climate/secure/docs/2021secure/basinreports/ColoradoBasin.pdf
The Summary report distills the more detailed information in the assessment report and basin reports describes actions taken to increase water supply reliability since the 2016 Report.
- Reclamation. (2021a). Water Reliability in the West—2021 SECURE Water Act Report. Bureau of Reclamation. 60 pp. https://www.usbr.gov/climate/secure/docs/2021secure/2021SECUREReport.pdf
Reclamation has also developed a web portal to present highlights of the reports and additional background information, including visualization tools for the West-wide projections of annual temperature and precipitation changes by the mid-21st century.