Aspen: City Council approves instream flow for the Roaring Fork River through town

Map of the Roaring Fork River watershed via the Roaring Fork Conservancy
Map of the Roaring Fork River watershed via the Roaring Fork Conservancy

From the Aspen Daily News (Brent Gardner-Smith):

In an effort to improve the aquatic environment of the Roaring Fork River as it flows through central Aspen, the city of Aspen has agreed to leave 2 to 3 cubic feet per second (cfs) of water in the river during low-flow periods this summer instead of diverting it into the Wheeler Ditch.

The Wheeler Ditch diverts water from the Fork a short distance downstream from the Aspen Club pedestrian bridge and just below Ute Park, east of Aspen. The headgate for the irrigation ditch is on the left side of the river, when looking downstream, and is visible from the upper end of the city’s Wheeler Ditch Trail.

The water in the ditch is typically used to supply small channels in the downtown pedestrian malls, to irrigate some city property, and to keep a base flow running through the city’s stormwater system.

The Aspen city council on Monday approved an agreement with the nonprofit Colorado Water Trust to leave the water in the river when river flows drop below 32 cfs, the amount identified by the state as necessary to protect the river’s environment “to a reasonable degree.”[…]

It’s the second year the city has entered into such an agreement with the Water Trust, which works to bolster flows in rivers across the state.

Last year the city announced that it would leave between 6 and 8 cfs of water in the river, but experience showed that it was more practical to leave 2 to 3 cfs, according David Hornbacher, the director of utilities and environmental initiatives for the city.

The city owns an 1889 senior water right to divert up to 10 cfs from the Fork into the Wheeler Ditch.

The agreement with the Water Trust says the city will begin bypassing water from the Wheeler Ditch when the river drops below 32 cfs. If the river drops to 31 cfs, the city will bypass 1 cfs, and so on, until the point when there is at least one cfs left in the ditch…

“The Water Trust brings structure to the effort,” Hornbacher said. “They bring resources. And they provide a framework to work toward other future agreements to benefit the river.”[…]

This year, Twin Lakes expects to divert about 55,000 acre-feet of water from the headwaters of the Roaring Fork.

Further downstream and just east of Aspen, the Salvation Ditch in mid-to-late summer often diverts more water than is left in the river below the ditch’s diversion structure…

The Salvation Ditch, which has a water right from 1902 to divert 58 cfs, was diverting 17.4 cfs that day, leaving 7.6 cfs of water flowing in the Fork.

Another 2.4 cfs was then diverted into the Wheeler Ditch that day, leaving just 5.2 cfs flowing in the river as it made its way past Rio Grande Park, the Aspen Art Museum, and under the Mill Street Bridge.

That’s a far cry from the 32 cfs the state says is required to protect the river’s aquatic environment, and the city’s effort this summer is intended to help close such gaps.

“I appreciate the city’s leadership, as it can help start the conversation,” said [Amy Beatie] of the Water Trust. “We would love everyone to really sit down and think about what they have and how they could use it strategically to put water back in the river.”

More Roaring Fork River watershed coverage here and here.

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