In years past, there have been proposals to divert water out of the Yampa River, the last major undammed tributary in the Colorado River system, for use on Colorado's Front Range. None has ever been approved. Now, however, a Colorado man is seeking approval to divert 55,000 acre-feet of water a year from the Green River in Utah just upstream of Dinosaur National Monument to Colorado's Front Range.

A Colorado man wants to divert 55,000 acre-feet of water a year from the Green River just upstream of the Gates of Lodore in Dinosaur National Monument/Kurt Repanshek

As outlined by Aaron P. Million, the managing member of Water Horse Resources, LLC, the diversion near Browns Park would be used to provide water for "irrigation, stockwatering domestic, commerical, municipal, mining and industrial" uses. But there's great opposition to the project, including from both the state of Utah and the Interior Department on behalf of the National Park Service, U.S. Bureau of Land Management, and U.S. Fish and Wildlife Service. 

The company's proposal maintains the 55,000 acre-feet is a legal withdrawal under the Colorado River Compact of 1922, as well as the 1948 Upper Colorado River Basin Compact. And while it maintains that "there is sufficient water within the source (the Green River) to (1) meet the portion of the state of Colorado's allocation under the Colorado River Compact attributable to this application, (2) meet Utah's allocation and approved uses within the Green River drainage, and (3) provide sufficient flow to protect and assist in recovery of endangered fish populations and critical habitat," those are key points of debate.

The risks downstream of this proposed diversion, which would feed the water into a hundreds-of-miles-long pipeline that would be aided by an "inline hydroelectric energy facility, could be significant.

Across the landscape that the Colorado River basin cradles stand 11 units of the National Park System, from Rocky Mountain National Park at the river's headwaters to Lake Mead National Recreation Area in Nevada. Recent years of drought have raised concerns about adverse impacts not just on the parks touched by the river system, but on storage in Lake Powell for hydroelectric generation as well as agricultural, and industrial demands throughout the basin. Too, there's currently a move underway in Utah to build a pipeline to divert water from Lake Powell to the St. George area in the southwestern corner of the state.

Additional diversions from the river system could impact endangered species that rely on river flows, wildlife, and recreation in Dinosaur, Canyonlands, and Grand Canyon national parks, the Interior Department noted in its comments provided to the Utah State Engineer, who is reviewing the proposal.

"Substantial diversions of water from the Green River could ultimately affect Lake Powell surface elevation levels and may affect release volumes," wrote James E. Karkut, an Interior Department attorney, in the department's comments. "This would have potential impacts on water-dependent resources and recreation at Glen Canyon National Recreation Area and possibly Grand Canyon National Park, which in turn triggers concerns about resources in Lake Mead National Recreation Area, and economic impacts on these NPS areas and surrounding communities."

Mark Foust, superintendent of Dinosaur National Monument, said Friday that the proposal in its current form contains too many unknowns. How would the proposed diversions impact the river ecosystem in his park, recreation, and even the economies of towns along the Green and Colorado rivers, he wondered? And if the project is approved, how would that affect levels of the Flaming Gorge Reservoir just upstream that impedes the Green on its journey south?

"It also all depends on the timing of taking amounts of water out. When would it be, and what would the impacts be to the (Flaming Gorge) reservoir level," Superintendent Foust said. "There are some concerns about what are we going to be seeing down the road? What will Flaming Gorge levels be in serious drought conditions?”

The Colorado River system just can't support such new diversion requests, according to Living Rivers and Colorado Riverkeeper, two of the conservation groups opposing the request.

"The yield of the Colorado River has been dropping 1 million acre-feet every 50 years, and it is well-known that this trend will continue for the rest of the 21st century," the groups wrote in their protest. "Non-adjudicated federal water rights in the Colorado River Basin, specifically for Native American tribes, are another factor that makes further upstream diversions unjustifiable. ... No state in the Colorado River Basin has ever adapted to the hydrologic cycle. This includes the climate of the past, the present, and certainly the climate of the future."

Indeed, the Interior Department's protest (attached below) contends that Water Horse Resources has not provided evidence "that the proposed project is hydrologically feasible..."

"It remains unclear how much water is actually available and unappropriated within the Green River Basin under the 1922 and 1945 compacts, especially given possible future climate scenarios," wrote Mr. Karkut. "The proposed project has not been thoroughly described in terms of water reliability. Before any decision could be made on the application, the applicant must demonstrate (or define the hydrologic conditions under which) 55,000 (acre feet per year) is available for export outside the Green River Basin."

A protest was also filed by the National Parks Conservation Association.

“NPCA is concerned that this diversion – enough to fill more than 271,000 Olympic-sized swimming pools – could pose risks to sensitive aquatic ecosystems inside Dinosaur National Monument and further downstream in the Colorado River, as well as to local recreation and tourism economies," said Vanessa Mazal, the group's senior Colorado program manager. "The Green River itself houses four endangered fish species that the National Park Service and other agencies are working vigilantly to restore.

"... The Colorado River and its tributaries, like the Green, are already under increasing pressure from drought, population growth, invasive species, dams and diversions, and other factors," she added. "Southwest states should be taking every possible action to improve this threatened water system, including rejecting this perilous proposal.”

This is not Mr. Million's first effort to divert water from the Green River for the Front Range. Back in 2012 the Federal Energy Regulatory Commission rejected his application to divert 200,000 acre-feet of water from the Flaming Gorge Dam on the river to the Front Range.