Nebraska v. Wyoming
Headline: Apportioning North Platte water, the Court limited Colorado and Wyoming irrigation and storage, allocated natural summer flows largely to Nebraska, and preserved federal reclamation contracts affecting three states’ farms.
Holding: The Court apportioned the North Platte River’s natural summer flow—25% to Wyoming and 75% to Nebraska—enjoined specified Colorado and Wyoming diversions and storage limits, and left federal storage contracts intact.
- Limits Colorado irrigation acreage and storage and caps its exports over ten years.
- Gives Nebraska 75% of natural summer flow between Guernsey and Tri-State.
- Preserves federal project contracts while requiring gauging and records for enforcement.
Summary
Background
Nebraska sued Wyoming (and impleaded Colorado) over use of North Platte River water for irrigation after long droughts and large federal reclamation projects. The United States intervened because of federal reservoirs (Pathfinder, Guernsey, Seminoe, Alcova) and contracts to deliver stored water. A Special Master held extensive hearings and reported detailed measurements of diversions, storage, return flows, and drought-era shortages from about 1931–1940.
Reasoning
The Court found the dependable natural flow during the irrigation season to be over-appropriated and that a genuine interstate controversy existed. It applied an equitable apportionment approach that gives priority weight to earlier rights but permits adjustments for established uses, return flows, and federal contracts. The Court refused to treat federal storage as automatically state-less property and left storage distribution under existing contracts. It imposed limits: Colorado (135,000 irrigated acres, 17,000 acre-feet storage, capped exports over ten years), Wyoming (limits on acreage and storage above Pathfinder), a defined priority order for reservoirs, and a 25% (Wyoming) / 75% (Nebraska) split of natural flow between Guernsey and Tri-State for May 1–September 30. The Court retained power to adjust the decree if conditions change.
Real world impact
Irrigators and irrigation districts in all three states must operate within new acreage, diversion, and storage limits. Federal project operators and Warren Act contractors keep their contractual delivery rights, but reservoir operations are constrained to protect senior downstream uses. The decree requires gauging, recordkeeping, and preserves a procedure to modify allocations when supply or projects change.
Dissents or concurrances
Justice Roberts (joined by Justices Frankfurter and Rutledge) dissented, arguing the Court overreached without clear present injury and warned against making the Court a continuing supervisor of interstate water administration.
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