As drought and over-allocation of Colorado River water shock the West, two lawsuits raise serious questions about irrigation in Wyoming and state plans to build a new dam and reservoir in Carbon County.
As soon as the federal government announced that it would cut Colorado River supplies to California, Nevada and Arizona, Nevada went to court claiming that the headwater states of Wyoming, Colorado, New Mexico and Utah could more easily handle the reductions.
At the same time, Colorado conservationists argued in court that Denver’s plans to pour Colorado River water into an enlarged reservoir for the city’s use amounts to building an $819 million bathtub that might never be filled.
Together, the lawsuits raise legal arguments regarding Wyoming’s reliance on irrigation water from the Green and Little Snake rivers, whether ranchers would still have access to traditional diversions and whether a proposed dam and reservoir above the Little Snake River valley is feasible and worthwhile.
The Nevada lawsuit is a direct challenge to Interior Secretary Doug Burgum’s plan to cut allocations to three of the seven states that rely on Colorado River flows — Nevada, California and Arizona. Burgum’s Aug. 21 approval of the new allocations left the headwater states of Wyoming, Colorado, Utah and New Mexico largely untouched.
But Burgum made “no analysis of the very real and dire economic effects to millions of municipal water users if the taps are turned off or water use must be significantly curtailed,” the Silver State’s lawsuit asserts. Instead, Nevada says, Wyoming and its headwater-state cohorts, “where water conservation has been less of a priority … have additional lower-cost options to respond [to] reduced … water deliveries.”
Three weeks before Burgum’s decree, conservation groups were in the 10th Circuit Court of Appeals in Santa Fe arguing that the city of Denver shouldn’t be allowed to complete an expansion of the Gross Dam that would bolster the city’s supplies with water from the Colorado River Basin. Among other reasons, conservation lawyers argued the city was squandering taxpayer money on a boondoggle.
“They’re building a giant bathtub, even though there’s likely no water to ever fill it,” attorney William Eubanks said on behalf of the river-protection group Save the Colorado.
Collectively the cases raise questions regarding whether Wyoming irrigators will continue to receive their traditional shares of Colorado River Basin water and whether Wyoming’s plan to build the West Fork Dam and reservoir above the Little Snake River Valley makes sense and will be challenged.
Should Wyoming share the pain?
River flows have declined from some 14.6 million acre-feet to about 12.3 million acre-feet, the Nevada lawsuit states, underscoring the shortage. Nevada’s challenge could upend what so far has been an easy ride for Upper Basin states, including Wyoming.
Wyoming was pleased with Burgum’s plan for the Colorado River because the plan would impose no administrative cuts to the state’s 7% share of river flows. Wyoming believes it has not yet used what it’s entitled to and has plans to construct the West Fork Dam on Carbon County’s Battle Creek to impound 10,000 acre-feet and irrigate every year with 6,000 acre-feet from the proposed reservoir.

But while Wyoming might skate under Burgum’s plan, the suit states Burgum didn’t consider whether “to equitably reduce water distributions … between the Upper Basin States and Lower Basin States.” In other words, Nevada wants Burgum to consider mandatory cuts to Wyoming’s water use, not just voluntary ones that Burgum endorsed.
Nevada makes its case by arguing it has “a relatively meager 3.3%” of the water apportioned to the Lower Basin States and Mexico,” but that amount accounts for 90% of what’s used in the Las Vegas Valley. That region has taken significant efforts to conserve water, the suit states.
Burgum’s plan was forged without detailed consideration of impacts to Nevada residents and in violation of environmental and procedural laws, the suit states. That misstep comes with real-world consequences, Nevada claims.
As a result of flawed analyses, Burgum “obscure[s] the full extent of economic and social costs to cities like Las Vegas, North Las Vegas, Boulder City, and Henderson,” a region with an $180 billion annual economy, the suit states.
The solution may lie upstream in headwater states, the suit contends, where water conservation has been less of a priority and lower-cost options abound.
Nevada wants the Burgum plan, a 10-year program, blocked and struck down.
Water for Wyoming’s new reservoir?
The Denver water lawsuit and challenge to the city’s Gross Dam enlargement has been ongoing for years and has produced more detailed arguments and criticism that could have implications across the West. The lawyer representing conservationists said the city and federal government didn’t look deep enough into drought and climate change.
Those planners “never analyzed whether there will be any average-to-wet years in which Denver can divert the water under its existing water rights, let alone whether there will be enough of those years to ever fill this expanded reservoir of 72,000 acre-feet,” Eubanks told the court.
Denver and federal officials did not “demonstrate that there would actually be enough water during these average-to-wet years to fill this reservoir,” he said. Too, there would be “massive environmental destruction on both sides of the Continental Divide.”
Planners also failed to consider many other options to satisfy Denver’s water needs, critics say. The city’s lawyer, and one representing the federal government, argued the opposite — that relevant factors were taken into account and that there would be enough water — diverted across the Continental Divide — to fill the new storage space.
A group of natural resource law professors filed a brief supporting the conservation groups and slamming the government for not taking climate change and drought into account. In its evaluation of the Goss Dam expansion, the federal government “entirely neglected to consider the potential environmental consequences of diverting water out of a Basin experiencing its worst period of drought in over a thousand years,” the 11 experts stated.
“The proposed project on Little Snake River drainage is probably the most threatened by what’s going on in the Colorado River.”
Gary Wockner
Gary Wockner, executive director of the 17-year-old Save the Colorado nonprofit, said drought could lead to mandatory cuts to Wyoming’s water use, potentially rendering the proposed West Fork Dam useless.
“Ranchers and farmers are likely going to be subject to being forced to send water downstream,” he told WyoFile. “The proposed project on Little Snake River drainage is probably the most threatened by what’s going on in the Colorado River because it’s solely for a handful of ranchers.
“If you follow just the politics of how this is playing out,” he said, “the bullseye is on agricultural water. There are more members in the U.S. House of Representatives in Southern California, in the areas that get Colorado River water, than there are in the rest of the Colorado River Basin combined.”

