Water from Colorado’s West Slope basins is essential for the economy and the natural ecosystems of seven western U.S. states. However, a recent study indicates that even under mild climate scenarios, these basins could reach a critical point where their traditional water delivery to Lake Powell and other key locations may no longer be viable.
Water from Colorado’s West Slope basins is essential for the economy and the natural ecosystems of seven western U.S. states. However, a recent study indicates that even under mild climate scenarios, these basins could reach a critical point where their traditional water delivery to Lake Powell and other key locations may no longer be viable.
The study, featured in the journal Earth’s Future, is the most significant and thorough analysis of drought vulnerability in the Colorado West Slope basins, which consist of six watersheds that contribute to the Lake Powell reservoir and support a $5 billion agriculture industry annually. This finding comes at a crucial moment as state and federal officials are negotiating water-sharing agreements that are set to expire soon.
Patrick Reed, the senior author of the study and a professor at Cornell’s School of Civil and Environmental Engineering, stated that the research aimed to enhance understanding of the limitations of current management practices and identify where new sustainable strategies could be applied effectively.
By integrating Colorado’s water planning model, StateMod, with a new hidden Markov modeling framework, the study generated hundreds of thousands of streamflow scenarios under both historical conditions and projected climate change. The results suggest that drought vulnerability assessments that rely solely on historical streamflow data may significantly downplay the severity and impact of potential droughts on water storage, agriculture, and municipal water supplies.
“Our findings indicate that even moderate climate change and decreases in streamflow in these basins could put the system at risk of reaching a tipping point, making it difficult to maintain the water delivery levels to Lake Powell that we’ve been used to historically,” said Reed.
In 2021, drought conditions caused Lake Powell to drop to unprecedented levels, leading the U.S. Bureau of Reclamation to declare the first-ever water shortage in the Upper Colorado River Basin. The study reveals that such shortages can occur due to internal variability within the basins, even without climate change, and that drought impacts are not confined to individual basins; their collective effects place even greater strain on the entire region.
“This highlights the importance of advanced drought analysis techniques that can address these widespread interconnected impacts,” commented David. F. Gold, the study’s lead author and an assistant professor of physical geography at Utrecht University, who conducted this research as a postdoc at Cornell.
Gold also pointed out that the modeling approach used here provides a framework for further investigations into drought vulnerability in complex river basins worldwide.
The research received support from the U.S. Department of Energy’s Office of Science as part of the Multisector Dynamics area within the Earth and Environmental System Modeling program.
