For decades, hydrologists believed most spring snowmelt rapidly enters rivers and streams. But a new study from the University of Utah shows that most of it spends years as groundwater before it spills into reservoirs – new research that could help western water managers and farmers better plan each year. Researchers collected runoff samples from river basins at 42 sites across the Mountain West, including Colorado, Idaho, New Mexico, Wyoming and Utah. They used what’s called tritium isotope analysis to determine the age of the water. In other words, they were figuring out how much time had elapsed since the water flowing in the stream was snow falling in the mountains. Researchers found that a snowflake that falls and melts will spend, on average, five years as groundwater before it seeps into mountain streams. That means there’s a whole lot more water stored underground than water managers account for.

Other snowmelt news:

• Denver Gazette (Colo.): Low water levels prompt mandatory fishing closure on stretch of river in Colorado
• Sky-Hi News (Granby, Colo.): Grand on drought watch as high temps hasten snowmelt
• Aspen Times (Colo.): On the fly: Reading the runoff tea leaves 
• Standard Examiner (Ogden, Utah): Runoff below average but reservoirs expected to fill as spring moves along in Northern Utah