Governor Polis, Attorney General Weiser urge Supreme Court to reject Nebraska case on South Platte River
Oct. 15, 2025 (DENVER) – Governor Jared Polis and Attorney General Phil Weiser today urged the U.S. Supreme Court to reject a case about the South Platte River Compact and Nebraska’s efforts to build the Perkins County Canal. Colorado is complying with its obligations under the compact and not obstructing Nebraska’s efforts to build the canal, so there is nothing for the court to review at this time, according to a brief filed with the court.
The South Platte River originates in Colorado and supplies water for the state’s biggest cities and some of its most productive agricultural lands. The river starts in the Rocky Mountains and winds roughly 380 miles northeast into Nebraska. The South Platte River Compact is an agreement that establishes the States’ rights and responsibilities to use water on the river.
While Colorado recognizes Nebraska’s right to build the Perkins County Canal, Nebraska has failed to move forward on the project for over 100 years. Recently, Nebraska officials have taken preliminary steps to plan and permit the project through the U.S. Army Corps of Engineers, but numerous steps lie ahead during which Nebraska, and others who might be affected by the project, will identify potential issues and fully study any impacts.
Nebraska appears to be using the prospect of the canal and this request for Supreme Court review as leverage to renegotiate the South Platte River Compact. Colorado will ensure that Nebraska honors the letter of the compact, just as Colorado always has.
“Water is the lifeblood of our state. We have always faithfully honored the century-old South Platte Compact and all other water agreements with our downstream neighbor states, and we will continue to do so. We refuse to sit idly by while Nebraska chases a meritless lawsuit that threatens Colorado’s precious water resources, our robust agriculture industry, and our rural communities in Northeastern Colorado,” said Governor Polis.
Attorney General Weiser said Colorado is complying with the compact and not interfering with Nebraska’s efforts to build the canal. As such, Nebraska hasn’t raised any claims ripe for Supreme Court review, and whatever issues arise in the future can be addressed through federal permitting processes or lower courts.
“Nebraska’s claimed violations rely on a mix of speculative and premature allegations. To the extent any legal issues arise in the future, there are alternative forums to resolve them. The Supreme Court need not and should not take a case that would put the court and the parties on a long, time-intensive, and expensive path that might well, in the end, put the States right back where they were before Nebraska filed their proposed complaint,” said Attorney General Weiser. “Even if the court decides to take up part or all of Nebraska’s case, I’m confident we will win on the merits. Both the facts and the law are on our side.”
Nebraska’s claims that Colorado authorizes water uses that harm Nebraska during the irrigation season are not supported by facts. Jason Ullmann, the state engineer and director of the Division of Water Resources, said Nebraska has only recently suggested they were concerned that Colorado was not meeting its obligations during the irrigation season.
“For over 100 years the Colorado State Engineer’s Office has worked with Nebraska and performed the hard work of ensuring Colorado meets its compact obligations on the South Platte River. This means we make difficult decisions every day on who receives their water and when based on the priority system and compact terms. As a result, water users in Colorado and Nebraska all receive their allotted share,” said Ullmann. “We were surprised and disappointed by Nebraska’s lawsuit and are hopeful once all the briefs are filed that we can resume discussions to meet the mutual needs of both of our States.”
The Supreme Court has original and exclusive jurisdiction over interstate disputes, such as border disputes and water rights. States must file a motion for leave to file a bill of complaint to bring a case to the court. The Supreme Court must still decide whether to accept the case.
The case is Nebraska v. Colorado, case number 220161.
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