Click the link to read the article on the Water Education Colorado website (Shannon Mullane):
September 4, 2025
The points and counterpoints are in: Colorado’s water heavyweights have laid out their arguments about the future of a powerful Colorado River water right ahead of a state hearing in mid-September.
A Western Slope coalition led by the Colorado River District and Front Range groups — Aurora Water, Colorado Springs Utilities, Denver Water and Northern Water — are debating a potential change to water rights tied to the Shoshone Power Plant in Glenwood Canyon. The influential water rights, owned by an Xcel Energy subsidiary, impact how water flows across the state.
The Western Slope wants to add an environmental use to the water rights, which currently allow Xcel to use the water for hydropower, mining, milling, manufacturing and other purposes. It’s part of the coalition’s broad plan to keep the Colorado River’s “status quo” flows at Shoshone Power Plant long into the future.
Front Range water managers and providers are concerned that their water supplies could be impacted, especially if the Colorado River District is overestimating the amount of water that should head west toward Shoshone, near Glenwood Springs, rather than east to growing Front Range cities.
Each side has insinuated that the other is swaying its estimate of past water use to send more water to their part of the state.
“We do not contest the environmental benefits. Protecting flows in Glenwood Canyon is valuable,” said Aurora Water in a rebuttal statement filed Friday. “Aurora’s participation in this hearing is not about securing any sort of ‘windfall,’ as some have wrongly alleged. That claim is baseless and pure projection. Our sole position is that Shoshone should be preserved as it has historically operated — no more, no less.”
Thirteen entities submitted rebuttal statements, totaling 367 pages,[to] the Colorado Water Conservation Board. It’s part of the state’s multistep review process in advance of the hearing at the board’s next meeting, Sept. 16-18.
For western Colorado communities, the Shoshone water rights impact their economies, quality of life and environments. Shoshone’s water rights are old enough that they have priority over other, more recent water rights in dry periods under state law. Over the past century, these communities have grown up relying on the power plant to send water westward — toward their farm diversions and rafting corridors — as it generates electricity.
For Front Range communities, the stakes are similar. Water providers rely on water from western Colorado to support growing cities, industries and farms. And in some cases, their water rights come in second to Shoshone’s under the “first in time, first in right” water administration system.
With high stakes on either side, Fresh Water News is breaking down some of the key questions in the debate.
What is an instream flow right?
An instream flow right is meant to help preserve the natural environment. In 1973, Colorado lawmakers allowed a state agency, the Colorado Water Conservation Board, to use water rights to keep water in rivers, streams and natural lakes through the Instream Flow Program.
At the time, Coloradans were concerned about stretches of streams that dried up when mountain runoff slowed while demand from humans — cities, farms and industries — continued. Shallower, slower streamflows impact habitat and food sources for native species while sometimes creating better habitat for their competitors.
The program aims to keep water in streams and natural lakes to reduce these impacts. Since 1973, the state has appropriated instream flow rights on nearly 1,700 stream segments covering more than 9,700 miles. In Shoshone’s case, the instream flow right would apply to a 2.4-mile stretch of the Colorado River between the point where Shoshone takes water out of the river and the point where it releases that water back into the river channel.
What’s this state-led process?
The state-led process will determine whether the water rights attached to the Shoshone Power Plant can be used to protect instream flows.
Colorado lawmakers designated the Colorado Water Conservation Board, a state water policy agency, as the sole entity that can own and operate instream flow rights. The agency’s board of directors is reviewing testimony, environmental analyses, and other materials as part of a standard, 120-day review process for proposed instream flow rights. The board is scheduled to make its final determination at its September meeting.
The Colorado River District kicked off the review period in May when it formally proposed adding an instream flow right to Shoshone’s water rights. Under the district’s proposal, the district would own the title to Shoshone’s water rights, but the state would manage it in perpetuity.
After the hearing, the proposed Shoshone environmental water right would also need to go through a water court process.
What is this “historical use” debate about?
In order to legally change Shoshone’s water rights to include environmental use, state officials need to know how much water has been used under Shoshone’s water rights in the past.
Shoshone’s 1905 water right allows the power plant to divert up to 1,250 cubic feet per second of water. A second, more recent, water right allows the plant to divert 158 cfs. But the amount of water that is actually used to generate power at Shoshone fluctuates or has paused because of facility maintenance.
Calculating past use is complicated. BBA Water Consultants, hired by the Colorado River District, looked at Shoshone’s operations from 1975 through 2003. The plant’s 29-year average historical use was 844,644 acre-feet, according to the consultants’ preliminary analysis.
They excluded years after 2003 because Shoshone had significant outages totaling 1,466 days over 19 years compared with 89 days during the study period.
Some Front Range water users say this estimate is too high or that more recent years should have been included.
Aurora Water said the Western Slope group used “cherry-picked data” and the historical use was closer to 538,204 acre-feet, a 36% difference.
Are there other disagreements?
In short, yes. The oft-repeated refrain in water deals is “the devil’s in the details.”
Colorado Springs Utilities raised concerns in its rebuttal about adding an environmental use to Shoshone’s more recent, or junior, water right, which currently allows water to be used for manufacturing and power generation. The Colorado River District’s plan would expand the junior right and potentially cause a water-administration ripple effect that would impact the utility’s water supplies.
Denver Water was concerned about historical use. It and Aurora Water also took issue with how the environmental water right would be owned and managed under the Colorado River District’s proposal. State lawmakers gave the CWCB exclusive authority to hold and use instream flow rights, but the River District’s plan encroaches on that authority by saying the district will hold the title, but the state agency will manage the right.
Northern Water shared many of these concerns, requesting that the state delay its decision.
For its part, the Colorado River District said everyone agrees on the main issue — adding an environmental use to the Shoshone water rights — but that the objectors “misstate the law” and are trying to distort the parameters of the state’s upcoming decision.
The district says the water court decides how much water is at stake, saying the water providers should leave “historical use” up to the court. It has also suggested the state stay neutral on the historical use amount.
