Winters v. United States (1908)

Situation: Starting with the Treaty of Fort Laramie (1851) and continuing through 4 later agreements (1855, 1874, 1888, 1896) Montana tribes -- the Gros Ventre, Assiniboine, Blackfeet, Piegan, Blood, and River Crow -- began ceding lands to the United States government. The 1888 and 1896 agreements fixed the current boundaries of the Fort Belknap reservation, carved from aboriginal lands of the Gros Ventre and Assiniboine peoples. The northern reservation boundary was the "middle of the main channel of Milk River." After 1888, white homesteaders began settling lands around the reservation and drawing off water for irrigation and stockwatering. 1905 was a severe drought year, and upstream irrigation bled the river all but dry, leaving little water for reservation and other downstream users. The federal government sued on behalf of the Fort Belknap tribes to protect their rights to Milk River water.

Decision: The US Supreme Court upheld lower court rulings in favor of the tribes. These rulings said that upstream users could not do anything -- such as build dams or reservoirs -- that would prevent a sufficient amount of water for irrigation from reaching reservation lands.

Implications: This case is significant not only for its decision in favor of the tribes but also for the reasoning that led to it. The court reasoned that even though no treaty or written agreement between the Fort Belknap tribes and the government said anything explicit about water rights, rights to water were nonetheless implied in order to fulfill provisions that were stated explicitly. The court based its reasoning on the section of the 1888 agreement which said: "whereas the said Indians are desirous of disposing of so much [land] as they do not require, in order to obtain the means to enable them to become self-supporting, as a pastoral and agricultural people, and to educate their children in the paths of civilization: Therefore, to carry out such purpose, it is hereby agreed . . ." In other words, the agreement states explicitly that reservation lands were set aside so that tribal people could "become self-supporting . . . pastoral and agricultural people . . ." The court then filled in the legal blanks with a commonplace assumption: land without water is valueless, particularly if the purpose of the land is to make self-sufficient farming and ranching possible. Therefore, water is reserved along with the land.

This case set a precedent for later tribal water rights cases, for example Arizona v. California. But courts have also used the "Winters' rights" doctrine -- reserving sufficient water to fulfill the purpose of reserved land -- in deciding water rights for other kinds of reserved federal lands such as national forests and wilderness areas.