Upper Colorado River Basin 20th century droughts under 21st century warming: Plausible scenarios for the future

Climate Services
By: , and 



This study builds on a collaboration with a water resource management community of practice in the Upper Colorado River Basin to develop scenarios of future drought and assess impacts on water supply reliability. Water managers are concerned with the impacts of warming on water year streamflow, but uncertainties in projections of climate make the application of these projections to planning a challenge. Instead, water managers considered a plausible scenario for future drought to be historical droughts to which warming is added. We used a simple statistical model of water year streamflow with temperatures increased by 1 °C to 4 °C, and then examined reductions in flow and runoff efficiency (RE) with each degree of warming for the six droughts defined in the observed streamflow record. In order to place these results into a management context, we employed an existing framework for system reliability, and in particular, a vulnerability assessment for water delivery metrics. Using modeled streamflow resulting from 1 °C to 4 °C warming, we found vulnerable condition thresholds for the two water delivery metrics assessed, Upper Basin Shortage and Lees Ferry Deficit, were crossed relatively infrequently at +1 °C, but with a substantially increased frequency under additional warming. Results are more relevant to resource management because the impacts of warming on Upper Colorado River streamflow were assessed in the context of management metrics and vulnerability thresholds, in collaboration with members of the water management community of practice.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Upper Colorado River Basin 20th century droughts under 21st century warming: Plausible scenarios for the future
Series title Climate Services
DOI 10.1016/j.cliser.2020.100206
Volume 21
Year Published 2021
Language English
Publisher Elsevier
Contributing office(s) Northern Rocky Mountain Science Center
Description 100206, 11 p.
Country United States
State Wyoming, Utah, Colorado, New Mexico, Arizona
Other Geospatial Upper Colorado River Basin
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