New research shows that in the Salt Lake City region, for every increased Fahrenheit degree, a significant drop in the annual flow of streams is likely to occur.
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While the impacts of a temperature increase would vary among the region’s watersheds, it is predicted that the stream flow would decline by 1.8 to 6.5 percent for each degree of temperature rise, with an average reduction of 3.8 percent.
This drop will also have serious consequences for the city’s water supply as some of the creeks and streams will dry up several weeks earlier in the summer and fall.
“Many snow-dependent regions follow a consistent pattern in responding to warming,” said National Center for Atmospheric Research (NCAR) scientist Andrew Wood, a co-author of the paper. “But it’s important to drill down further to understand the sensitivity of watersheds that matter for individual water supply systems.”
“Many western water suppliers are aware that climate change will have impacts, but they don’t have detailed information that can help them plan for the future,” said lead author Tim Bardsley of the Cooperative Institute for Research in Environmental Sciences (CIRES).
The team relied on climate model projections of temperature and precipitation in the area, historical data analysis, and a detailed understanding of the region from which the city utility obtains water. The study also used NOAA streamflow forecasting models that provide information for Salt Lake City’s current water operations and management.
As a result of warmer temperatures, more of the region’s precipitation will fall as rain as opposed to snow, leading to earlier runoff and less water in creeks and streams in the late summer and fall. With peak water flow occurring earlier in the summer, it would create difficulties in meeting water demand as the summer irrigation season progresses.
The specifics in the new analysis include which creeks are likely to be affected most and soonest, how water sources on the nearby western flank of the Wasatch Mountains and the more distant eastern flank will fare.
“We are using the findings of this sensitivity analysis to better understand the range of impacts we might experience under climate change scenarios,” said co-author Laura Briefer, water resources manager at the Salt Lake City Department of Public Utilities. “This is the kind of tool we need to help us adapt to a changing climate, anticipate future changes, and make sound water-resource decisions.”
The findings are published in the journal Earth Interactions.
Read more at UCAR.
Oregon river image via Shutterstock.