Montana v. Wyoming - 563 U.S. 368, 131 S. Ct. 1765 (2011)

Rule:

The doctrine of appropriation provides that rights to water for irrigation are perfected and enforced in order of seniority, starting with the first person to divert water from a natural stream and apply it to a beneficial use (or to begin such a project, if diligently completed). The scope of the right is limited by the concept of beneficial use. That concept restricts a farmer to the amount of water that is necessary to irrigate his land by making a reasonable use of the water. Once such a water right is perfected, it is senior to any later appropriators' rights and may be fulfilled entirely before those junior appropriators get any water at all.

Facts:

Article V(A) of the Yellowstone River Compact (Compact) ratified by Montana, Wyoming, and North Dakota provides: “Appropriative rights to the beneficial uses of the water of the Yellowstone River System existing in each signatory State as of January 1, 1950, shall continue to be enjoyed in accordance with the laws governing the acquisition and use of water under the doctrine of appropriation.” 65 Stat. 666. Montana filed a bill of complaint, alleging that Wyoming breached Article V(A) by allowing its upstream pre-1950 water users to switch from flood to sprinkler irrigation, which increases crop consumption of water and decreases the volume of runoff and seepage returning to the river system. Thus, even if Wyoming's pre-1950 users divert the same quantity of water as before, less water reaches downstream users in Montana. Concluding that the Compact permits more efficient irrigation systems so long as the conserved water is used to irrigate the same acreage watered in 1950, the Special Master found that Montana's increased-efficiency allegation failed to state a claim. Montana has filed an exception.

Issue:

Did Wyoming's use of more efficient irrigation systems breach the river compact?

Answer:

No

Conclusion:

The U.S. Supreme Court held that Wyoming's use of more efficient irrigation systems did not breach the river compact since the compact incorporated the ordinary doctrine of appropriation without significant qualification, and the doctrine allowed appropriators of water to improve their irrigation systems, even to the detriment of downstream appropriators. Although the law concerning return flows was an unclear area of the appropriation doctrine, the change in Wyoming users' irrigation methods made no change in the acreage irrigated or the amount of water diverted, and thus did not injure the Montana users, and it appeared that irrigation improvements were considered to be within the scope of the right of appropriation. Further, the doctrine of recapture allowed Wyoming users to recapture and reuse their own runoff and seepage, and such a result was accomplished by the switch to more efficient irrigation systems.