SALT LAKE CITY—Climate change could throw a wrench into how Utah’s water supplies are managed.
The state is not only expected to get hotter in the coming decades but also see changes in annual precipitation, according to scientists at a conference Tuesday.
Northern Utah could see a 10 percent increase in winter precipitation by 2050 and summers could see a 10 percent drop, said Thomas Reichler, a University of Utah professor and researcher.
The timing of that precipitation—and whether it comes as snow or rain—could affect water storage.
Traditionally, mountain snow melting in the spring and stored in reservoirs has supplied year-round water for the state’s farms, businesses and homes.
But if that snow melts early due to warmer temperatures, or arrives as rain instead, it could create storage and supply problems for water managers, said Brian McInerney, a hydrologist with the National Weather Service in Salt Lake City.
McInerney was one of the organizers of the conference, called “Climate Change and Utah’s Water Supply” that gathered utility officials, water managers, state officials, academics and others to bring them up to speed on predictions for climate change in Utah.
Some of the changes, such as an increase in overall temperatures, are fairly well understood. Others, especially those dealing with precipitation, are more difficult to predict.
Reichler said his predictions—based on complicated statistical computations using 16 large-scale global climate models—are still rough but use the best information now available.
One of the limitations is that the models can’t predict whether winter precipitation will provide ample snowpack atop the mountains or simply arrive as rain and run off without getting stored for human use.
For decades, water managers across the West have relied on past precipitation patterns to help predict and plan for the future.
“Climate change challenges that assumption,” said Joe Barsugli, a climate scientist at the University of Colorado.
Water managers will be faced with—and in some cases are already facing—earlier spring snow melt, increased evaporation and other changes. They’ll have to find ways to adapt, though it may be too early to say exactly what the best methods might be, McInerney said.
For some that might mean more reservoirs, for others it could be underground storage facilities that limit the effects of warmer temperatures and evaporation.
The basic message for managers, McInerney said, is “brace for change.”
Robert Gillies, the Utah state climatologist and a Utah State University professor, said the state has warmed by about 3 degrees over the last 100 years. The amount of precipitation has also fallen.
He outlined a series of possibilities for Utah in the coming decades, including more forests vulnerable to wildfires, more rain rather than snow, and more dust blowing in from the west and coating the state’s famous mountain snow.
The conference was hosted by the National Weather Service and the University of Colorado.
