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.”
The Fork through the reach below the Wheeler Ditch and above Hunter Creek often drops below 32 cfs in late summer and fall due in large part to diversions off the top of the river, and from diversions into the Salvation Ditch, which takes water from the river at Stillwater Drive, upstream of the Aspen Club.
An ongoing experiment
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.
Under the agreement then, the city could, in theory, leave up to 9 cfs of water in the river. But, according to both Hornbacher and Amy Beatie, the executive director of the Water Trust, the city expects to bypass 2 to 3 cfs this summer.
While that’s not a great deal of water, the section of the Fork below the Wheeler Ditch and above Hunter Creek was running as low as 5 cfs during the dry summer of 2012.
Further, both the city and the Water Trust say the city’s agreement to leave water in has more value than just wet water in the river, as it may foster greater cooperation from other parties to leave water in this section of the Fork in future drought years.
“Doing this as a pilot project, our risk is minimal and our opportunities are high, both to benefit the river and to provide leadership toward potential partnerships,” said the city’s Hornbacher.
Water right at risk?
A water right can be weakened, and be subject to challenges, if the water tied to the right is not used for the purposes specified in a decree from the state. If a water right owner leaves water in a river and does not divert and put the water to a “beneficial use,” such as irrigation, then someone else can make a claim for the water.
But the city is willing to accept that low risk, Hornbacher said, especially as this is only a short-term pilot program. The city’s agreement with the Water Trust states that the agreement “does not indicate any abandonment or intention to abandon any portion of the water right, whatsoever.”
According to the resolution approving the deal, the city “currently has a water policy that directs staff to utilize the city’s water rights in a manner that seeks to improve instream flow conditions.”
The city’s private agreement with the Water Trust differs from an earlier program put together by the Trust to have short-term leases of water approved by the Colorado Water Conservation Board, which sets and manages instream flow rights in the state.
Beatie of the Water Trust said Aspen’s more informal approach provides the city with more flexibility.
And the city values the participation of the Water Trust in its efforts.
“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.”
The Roaring Fork through Aspen is a shadow of its natural self, as about 40 percent of the river’s natural flow has been diverted each year since 1935 under the Continental Divide by the Twin Lakes Reservoir and Canal Co., which is primarily owned by the city of Colorado Springs.
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.
A good example of that was provided by a “snapshot” assessment done on July 27, 2012 by S.K. Mason Environmental LLC.
It showed the Fork was flowing at 25 cfs that day below Difficult Creek and above the Salvation Ditch, which irrigates land as far downvalley as Woody Creek.
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 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.”
Editor’s note: Aspen Journalism and the Aspen Daily News are collaborating on coverage of water and rivers. The Daily News published a version of this story on Wednesday, April 30, 2014.