Rising heat to lower river flows, report says
Warming temperatures across Colorado will result in earlier spring melts, increased evaporation and drier soils, lessening the state’s water supply, according to a report released Monday by the Colorado Water Conservation Board.
The report, released ahead of a drought conference Gov. Bill Ritter will hold Wednesday through Friday in Denver, argues that Colorado’s average temperature will rise 2.5 degrees Fahrenheit by 2025 and 4 degrees by 2050.
“A synthesis of findings in this report suggests a reduction in total water supply by the mid-21st century,” the report said. “When combined with temperature increases and related changes in evaporation and soil moisture, all recent hydrologic projections show a decline in runoff for most of Colorado’s river basins by the mid-21st century.”
The report, compiled in a collaboration by the University of Colorado and the National Oceanic and Atmospheric Administration, warns that by 2050, the Western Slope’s river valleys will become more desert-like.
“In all seasons, the climate of the mountains is projected to migrate upward in elevation, and the climate of the desert southwest to progress up into the valleys of the Western Slope,” the report said.
Veva Deheza, section chief for the office of water conservation and drought planning at the Colorado Water Conservation Board, said the Colorado-speci-fic report is the first of its kind.
Deheza said the report only answers what will happen to the state’s water supply as a result of climate change and not in relation to demand.
She said future studies will probe the intersection of skyrocketing demand for water and climate change’s effect, lowering river flows.