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No flooding forecast yet for Roaring Fork

Scott Condon
The Aspen Times
Aspen, CO Colorado

ASPEN ” The “probable” peak flow of the Roaring Fork River is expected to be significantly higher than average but still below flood stage, the National Weather Service has determined.

The “most probable” peak for the Roaring Fork at Glenwood Springs is 8,500 cubic feet per second (cfs), according to the weather service’s Colorado Basin River Forecast Center. The average peak is 6,150 cfs.

If the forecast proves accurate, this year’s peak will be about 38 percent higher than average.



Even so, that would be far below what’s considered the flooding stage. The flood flow has been determined to be about 11,800 cfs. The forecast center said there is a 25 percent chance the flow will exceed the flood flow. There is a 10 percent chance of the flow topping 15,000 cfs.

The federal agency issues forecasts each month from March through June. The forecasts are designed to be a tool for everyone from water managers to emergency response officials to prepare for runoff. The preliminary estimates in March cannot factor in weather between now and early June, when peak runoff typically occurs.




“It’s important for people to know that anything can change,” said Rick Lofaro, executive director of the Roaring Fork Conservancy, a Basalt-based nonprofit that tracks river issues.

A long hot and dry spell could influence how quickly the snowpack melts and could affect the peak, for example. “If you remember last March, it was pretty tropical around here,” Lofaro said.

On the other hand, rainstorms in late May and early June can boost the peak flow.

The one thing people can count on, Lofaro said, is that the runoff will be higher than the Roaring Fork Valley has experienced in at least the last decade.

The U.S. Natural Resources Conservation Service (NRCS) forecasts the volume of water that streams will move during the runoff season rather than the peak runoff. The NRCS forecasts that the Roaring Fork’s volume will be 41 percent higher this year at Glenwood Springs.

The possibility of higher than average flows is strong for rivers and streams throughout the West, said Tom Pagano, a water supply forecaster for the NRCS’s National Water and Climate Center.

Streamflows are expected to be high because snowpacks are so high. In the Roaring Fork Valley, the snowpack was 49 percent above average as of Monday afternoon. That guarantees a higher runoff volume, regardless of what the weather does for the remainder of winter and spring.

“It’s not like it’s going to disappear overnight,” Pagano said.

So, weather can affect the peak flow ” the highest level that the river will reach during runoff ” but not have so much of an influence on the volume of water during the runoff period after a snowy winter like this.

Lofaro said high runoff will benefit the rivers and streams by flushing sediments downstream and dispersing them. Sediments harm the habitat for the water insects that trout in the Gold Medal waters of the Roaring Fork and Fryingpan Rivers depend on. A flushing flow frees up space between the rocks to create better habitat for those insects, Lofaro said.

There hasn’t been a truly beneficial flushing flow for about a decade, he said. So Lofaro and other conservationists hope this year’s runoff is high enough to benefit the ecosystem without causing problems for humans.

The Colorado Basin River Forecast Center said the Roaring Fork River’s normal peak period is between June 3 and 18.

scondon@aspentimes.com

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