A new NASA satellite is revealing major flaws in the computer models scientists use to understand rivers, including waterways across the American West.
Researchers found serious modeling errors in nearly 10% of the river stretches they studied worldwide. But those errors often occurred in waterways that are especially important for managing water supplies, generating hydropower and preparing for climate change.
The study, published in Geophysical Research Letters, compared global river models with observations from NASA's Surface Water and Ocean Topography satellite.
In some cases, the models showed rivers behaving oppositely to what the satellite observed.
“The satellite said, ‘river got deeper.’ And the model said, ‘nope, got shallower,’” said Colin Gleason, a professor at UMass Amherst who led the research.
In the Mountain West, researchers found persistent discrepancies along the Columbia River, whose tributaries reach into Idaho, and the Platte River system, which extends into Colorado and Wyoming.
Gleason said the biggest challenges often arise in waterways heavily influenced by dams and reservoirs. That's because models need to account for more than just how water naturally flows.
“You have to know economics, policy, history, environmental regulations; all the things that drive how a reservoir is being operated,” he said.
Those human decisions can affect when and how much water moves downstream, making it difficult for global models to accurately capture changing river conditions.
Gleason emphasized that specialized models used to manage major Western rivers are generally more accurate than the global models examined in the study.
But the new satellite observations could help researchers improve those broader models, particularly in places where direct measurements of rivers are limited.
As climate change puts growing pressure on Western water supplies, Gleason said getting those predictions right will become increasingly important.
Gleason hopes more researchers and water managers will take advantage of the satellite observations, which are available at no cost.
“These data exist. They’re free, they’re open, they’re public,” Gleason said.
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
