Colorado v. New Mexico

1984-08-02

Headline: Court rejects Colorado’s request to divert Vermejo River water, dismissing a proposed 4,000 acre-feet transfer and protecting New Mexico users while requiring stronger proof and planning for future diversions.

Holding: In an original action, the Court held that Colorado failed to prove by clear and convincing evidence that a 4,000 acre-feet diversion from the Vermejo River should be allowed and therefore dismissed Colorado’s claim.

Real World Impact:

Stops Colorado’s proposed 4,000 acre-feet diversion, keeping water available to New Mexico users.
Requires strong, specific evidence and planning before states can win interstate water transfers.
Raises pressure on states to monitor, conserve, and administer water systems more rigorously.

Topics: water rights, interstate water disputes, water conservation, industrial water use

Summary

Background

The dispute began when a Colorado corporation proposed in 1975 to take water from the Vermejo River to use in Colorado. The Vermejo starts in Colorado but most of its course and its main users are in New Mexico. A Special Master held a long trial and recommended permitting Colorado a diversion of up to 4,000 acre-feet per year. The Master based that recommendation on two ideas: that New Mexico could conserve enough water to offset the diversion, and that Colorado’s benefits would outweigh any harm.

Reasoning

The core question was whether Colorado proved strongly enough that the diversion should be allowed. The Court applied a clear-and-convincing-evidence standard (a high level of proof) and reviewed the Master’s detailed findings. The majority concluded Colorado did not offer specific, financially and physically feasible conservation plans or concrete, studied proposals for how it would use and manage the diverted water. For that reason, the Court found the record insufficient and dismissed Colorado’s claim.

Real world impact

As a result, the existing New Mexico users keep protection against the proposed transfer, and Colorado cannot divert the 4,000 acre-feet based on the present record. The decision requires parties seeking interstate diversions to present careful planning, studies, and specific conservation measures. The Special Master had identified several ways New Mexico could conserve and criticized lax administration, but the Court held Colorado must prove these offsets clearly before a diversion is allowed.

Dissents or concurrances

Justice Stevens dissented, arguing the Court should give greater deference to the Special Master and that the Master’s factual findings and suggested conservation measures were supported by the record and would justify the diversion.