- Nebraska files 55-page complaint citing compact violations.
- State claims over 1.3 million acre-feet diverted unlawfully.
- Governor Polis calls lawsuit “meritless” and vows to defend Colorado.
- Nebraska leaders say the case is essential to protect future water access.
Tuesday, July 22, 2025 — Nebraska has filed a lawsuit against Colorado in the United States Supreme Court, accusing its upstream neighbor of violating the 1923 South Platte River Compact
. The 55-page complaint, submitted on July 16, 2025, contends that Colorado has deprived Nebraska of legally guaranteed water and is obstructing construction of the Perkins County Canal—a project intended to secure winter-season flows for Nebraska agriculture and municipal needs.
The South Platte River Compact, ratified by both states and approved by Congress in 1926, governs how much water each state may use from the river during the irrigation and non-irrigation seasons. Nebraska asserts that Colorado has breached multiple provisions of the compact, resulting in reduced flows, failed crops, and escalating legal and political conflict between the states.
Nebraska Alleges Ongoing Harm to Farmers and Cities.
The complaint outlines two primary violations: first, that Colorado is allowing junior water users to divert water during the summer irrigation season, even when flows at the state line fall below the 120 cubic feet per second minimum; and second, that Colorado is interfering with Nebraska’s lawful right to construct the Perkins County Canal to access non-irrigation season flows.
According to Nebraska, the state has been deprived of over 1.3 million acre-feet of water due to these practices. The Western Irrigation District—one of Nebraska’s key South Platte water users—was forced to suspend nearly all surface water deliveries in 2022, the first such shutdown in nearly 50 years.
Nebraska further argues that Colorado’s increasing reliance on complex groundwater augmentation plans and water storage during the non-irrigation season undermines Nebraska’s ability to benefit from the compact. The complaint contends that these practices are inconsistent with the compact’s requirement for a self-executing and easily measurable administration system.
Nebraska Officials: “We Must Secure Our Water.”
In an official press release, Nebraska Attorney General Mike Hilgers stated:
“Today’s action will ensure that Nebraska receives all the water to which it is entitled under the Compact and that Nebraska’s agriculture and economy are protected. Our suit has two basic elements: First, it challenges Colorado’s ongoing, unauthorized overuse of Nebraska’s water during the summer and the rationale Colorado uses to justify it. Second, we challenge Colorado’s efforts to obstruct the construction of the Canal and prevent Nebraska from accessing the additional water Nebraska is entitled to in the South Platte River Compact. Water is the essential lifeblood of Nebraska’s economy, and it’s my goal to protect one of the state’s most important assets.”
Governor Jim Pillen added:
“Today’s action comes only after we made every reasonable effort to resolve our differences with Colorado. Ultimately, Nebraska must push forward to secure our water for future generations. Although we hoped to avoid a lawsuit, we are confident we remain on schedule to complete the Perkins County Canal by 2032.”
The state has already appropriated more than $628 million for canal planning and land acquisition. Officials say design is approximately 60 percent complete and legal teams are pursuing both voluntary purchases and potential eminent domain proceedings inside Colorado.
Colorado Responds: Lawsuit “Meritless.”
Colorado leaders strongly oppose the lawsuit. In a statement issued on July 16, Governor Jared Polis called the action an unnecessary escalation:
“I am disappointed that the States of Colorado and Nebraska will need to waste time and money in court over this meritless challenge. Colorado has always been in compliance with the South Platte Compact and other applicable agreements. We have also continued to meet in good faith with Nebraska, despite its attempts to intimidate Colorado landowners and damage our agricultural communities. This escalation by Nebraska is needless, and Colorado will take all steps necessary to aggressively defend Colorado water users, landowners, and our rural economy.”
Colorado Attorney General Phil Weiser has also voiced objections. Earlier this year, he warned that Nebraska’s use of eminent domain on Colorado land is legally unprecedented and likely to provoke a drawn-out legal battle. He further stated that the issue may need to be resolved by the U.S. Supreme Court before any construction can begin.
Local Resistance in Colorado.
Beyond state officials, Colorado landowners and water users have organized active opposition to the project. Sedgwick County commissioners have explored changes to local permitting rules under Colorado’s “1041 regulations” to obstruct construction. Water districts and municipal stakeholders have formed the South Platte Water Alliance to coordinate resistance, while individual project opponents have described Nebraska’s actions as an unjustified “land grab.”
Nebraska’s complaint accuses Colorado of using these local and regional actors to wage what it calls a “proxy war” against the canal. The state asserts that all such interference violates the compact, which explicitly grants Nebraska the right to acquire land for the project by purchase, prescription, or condemnation.
Legal Questions and Next Steps.
Nebraska is asking the U.S. Supreme Court to:
-
Declare and enforce Nebraska’s rights under the compact;
-
Prevent Colorado from obstructing canal construction or interfering with land acquisition;
-
Quantify and restore the water Nebraska has been denied;
-
Compel Colorado to stop future violations and forfeit any unjust economic gains;
-
Award legal costs and punitive damages.
Legal analysts say the case raises weighty constitutional and procedural questions. Chief among them: Can one state exercise eminent domain within another state’s borders? Is Nebraska’s canal right enforceable without additional approval from Colorado courts? And how should century-old water compacts be interpreted in light of changing hydrology and population growth?
Because the compact lacks a standing commission or dispute resolution mechanism, the U.S. Supreme Court is the only venue for resolving these issues. If the Court agrees to hear the case, litigation could span several years and involve the appointment of a special master, expert testimony on water availability, and detailed examination of hydrological data.
Broader Implications.
At stake is not only Nebraska’s access to water but also how western states will interpret and enforce interstate compacts amid increasing drought risk and demand for limited supplies. For Nebraska, the canal represents a long-deferred safeguard. For Colorado, it is a challenge to landowner rights and water security for rapidly growing communities.
The Supreme Court has not yet set a timeline for considering Nebraska’s filing. Colorado is now required to respond, after which the Court will decide whether to take the case under its original jurisdiction for disputes between states.
wpDiscuz