Western States Water Newsletter

 Addressing Water Needs and Strategies for a Sustainable Future



Streamflow in the Upper Colorado River Basin

On March 29, the U.S. Geological Survey (USGS) announced the results of a collaborative study published in the journal Science, titled “Colorado River Flow Dwindles as Warming-Driven Loss of Reflective Snow Energizes Evaporation.” Previous studies have had wide-ranging estimates of streamflow reduction per degree increase in temperature (1-8%), complicating the task of planning and management of water resources in snow-dominated river basins. The USGS Water Resources Mission Area and National Oceanic and Atmospheric Administration’s (NOAA) Geophysical Fluid Dynamics Laboratory used a new model and satellite-based observations of surface albedo and surface radiation. Identifying these mechanisms to explain the sensitivity of water flow to warming temperatures enables more confident projections. The USGS research “indicates that streamflow in the Upper Colorado River Basin is decreasing by about 5% per degree Fahrenheit as a consequence of atmospheric warming, causing a 20% reduction over the past century.”  See https://pubs.er.usgs.gov/publication/70209076.