The snowpack in Colorado’s mountains has reached 93% of normal, federal survey data showed Tuesday — lagging slightly at the moment when cities and food growers decide whether water supplies will be sufficient for crops, cattle and a growing population.
While recent heavy snow bodes well, measured in relation to the norm between 1981 and 2010, federal forecasters on Tuesday also warned they’re expecting “below normal” water flows in streams and rivers once snow melts due to decades of mostly increasing aridity.
“Our soil is pretty dry, and current stream flows are low, something that’s going to play into snowpack runoff,” said Brian Domonkos, the U.S. Department of Agriculture’s Colorado Snow Survey supervisor.
“Traditionally, if we had a snowpack at this level with normal soil moisture and base stream flows, we’d see better runoff. But as dry as things are, stream flow and soils, we’re expecting below normal runoff in most if not all river basins,” Domonkos said.
“We get less bang for the buck from snowpack. From a drought standpoint, this snow accumulation we’ve received in March does not offset the drought,” he said. “And from fire perspective, has this snowpack taken us out of fire concerns? Absolutely not.”
Colorado’s northern and eastern river basins generally received heavier snow.
Snowpack in the closely-watched Colorado River Basin — 40 million people and growers across seven western states rely on it — was at 89% of the norm.
Southwestern Colorado faced the driest conditions with snowpack measured in the combined San Miguel, Dolores, Animas and San Juan river watersheds at 87% of normal.
The South Platte River watershed had 102% of normal snowpack, and the level was 111% of the norm along the upper Rio Grande River. Arkansas River watershed snowpack was at 110%. In northern Colorado, snowpack along the Yampa and White rivers was at 91% of the norm, and the North Platte and Laramie watersheds had 97% of normal.
Mountain snowpack serves as a natural slow-release source of water tapped by farmers, cattle ranchers and cities. Climate warming has been shrinking snowpack and decreasing runoff into streams. Scientists have projected a sharply reduced contribution of melting snow in the Colorado River Basin to water available for growing crops.
Worldwide, more than 2 billion people depend on water that begins as snow. Reduced water flows from snowmelt have complicated food production in California, western China, South America, Central Asia and southern Europe.
Colorado mountain snowpack traditionally has peaked between now and mid-April. Water providers focus on that level knowing that rising temperatures soon will melt the snow, sending water into streams and rivers.
Denver Water planners have found that climate warming increases the uncertainty of precipitation and stream flows. And utility officials are counting on an expansion of Gross Reservoir, west of Boulder, to store more water from northern mountains. This will make Denver more resilient, the officials say, as snow becomes less predictable.
Agriculture uses about 85% of Colorado’s water supplies. Denver residents typically use around 80 gallons a day per person on average for all indoor and outdoor purposes. Conservationists are pushing for increased efficiency toward a target of 40 gallons for indoor use.
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