For the second year in a row, the City of Aspen has voluntarily closed the headgate of the City-owned Wheeler Ditch in an effort to improve flows in the Roaring Fork River. Flows in the river dropped below 32 cubic feet per second (“cfs”) on Wednesday, August 21, triggering an agreement between the City and the Colorado Water Trust designed to keep flows close to the 32 cfs mark, the amount of water necessary to preserve the natural environment in this section of river.

As the USA Pro Challenge bike race flew through picturesque Aspen on Monday, August 19, City of Aspen (City) staff were preparing to implement an innovative pilot program now in its second year between the City and the Colorado Water Trust (CWT). Historically, flows in the Roaring Fork through Aspen are low at this time of year—even in years with good snowpack. Climactic factors during spring and summer such as monsoon rains, temperature, and precipitation all impact streamflows, but administration on the river plays a big part in the amount of water flowing in the river. Water diversions serving various beneficial uses reduce the amount of water in the upper Roaring Fork River, so much so that, at times, less than ten percent of the native flow of the Roaring Fork reaches Aspen.

To catalyze long-term streamflow solutions for the Roaring Fork River, the City led local flow restoration efforts in 2013 by curtailing one of its senior water rights to bolster flows through a critical reach of the Roaring Fork River by 2–3 cfs until late season monsoon rains brought streamflows back up. To build on the success of last year’s pilot streamflow protection efforts and to provide water to the river in the irrigation season when it is often hardest hit by depletions, the Aspen City Council authorized another one-year non-diversion agreement with the Colorado Water Trust at its April 28, 2014 meeting. The agreement describes how and when the City would reduce the amount of water it diverts from the river at the Wheeler Ditch to increase streamflows.

Although 2013/2014 was a great snow year in the Roaring Fork valley, streamflow in the Roaring Fork River has been dropping steadily over the last few weeks. At the end of July, the Roaring Fork was flowing at 60 cfs, but little more than a week later, the river was flowing at 40 cfs (photo). As of Wednesday morning, flows had dropped below 32 cfs, the Colorado Water Conservation Board’s decreed instream flow rate and the amount needed to preserve the natural environment in this stretch of river.

For more information about this innovative pilot project aimed at understanding streamflows and exploring solutions for the Roaring Fork River, visit the City of Aspen’s project page on the Colorado Water Trust’s website.

Photo Caption: The Roaring Fork River near the Wheeler Ditch headgate just southeast of the City of Aspen was flowing at 40 cfs on August 11, 2014 as it winds its way through the Roaring Fork Valley. Photo Credit: Grand River Consulting.

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