Nebraska Urges Supreme Court to Hear South Platte Water Dispute

Nebraska officials are urging the U.S. Supreme Court to reject a request from Colorado to dismiss part of the state’s ongoing lawsuit over the South Platte River, nebraskapublicmedia.org reported.

The core dispute centers on whether Colorado is delivering the specific amount of irrigation water Nebraska is entitled to under the South Platte River Compact. Colorado maintains that it is fully complying with the interstate agreement.

In a court filing submitted Monday, Nebraska argued that the Supreme Court should continue reviewing its claim. The disagreement dates back to an initial lawsuit Nebraska filed in July 2025.

At issue is Colorado’s augmentation system. This practice allows certain farmers to use water during the irrigation season provided they replace it in the off-season so it can seep back into the river for the next cycle, according to nebraskapublicmedia.org.

Colorado contends that the system is scientifically sound. Nebraska counters that the labyrinthine setup makes it impossible to verify compliance.

Colorado recently asked the Supreme Court to dismiss Nebraska’s claim under Article VIII of the compact. That article requires Colorado officials to deliver water across the state line without requiring special legislation from the Colorado General Assembly. Colorado argues that Article VIII does not limit how the state ensures its compliance.

The compact dictates that Nebraska must receive 120 cubic feet of water per second at the state line near Julesburg, Colorado, during the irrigation season running from April 1 to October 15 every year. That volume is not strictly guaranteed, however. If the flow dips below that threshold, Colorado is required to limit its own irrigators’ water use.

Nebraska claims that years of these practices have deprived it of up to 1.3 million acre-feet of water. An acre-foot represents the amount of water required to cover an acre of ground to a depth of one foot.

A separate part of Nebraska’s lawsuit alleges that Colorado is blocking efforts to build the Perkins County Canal. That project, which is also authorized under the compact, would supply Nebraska with 500 cubic feet of water per second during the non-irrigation season.