Winters v. United States

This landmark ruling set U.S. policy regarding Native American water rights in the western United States. Agreements and treaties establishing Indian Reservations, though not explicitly claiming water rights, contained an implied reserved right to the amount of river water necessary to effectively pursue the purposes of the reservations. The decision created the Winters doctrine, defining a form of water right unique to Native American tribes.

After acquiring rights to the western lands from other European countries, the federal government still had to negotiate actual possession through treaties and agreements with the numerous Native American tribes. The newly gained property rights of the federal government included the power to dispose of the public lands and water in the West.

Two major systems of water rights are found in the United States. The water abundant states in the East established the riparian system. The more arid West applied an appropriative system. Under the riparian system, an owner of land that borders a stream has the right to make reasonable use of the water. The right is attached to the land and cannot be terminated even if not used. The owners are also entitled to continuation of the stream flow from the upstream source. The appropriative system operates quite differently. Water rights are not linked to the land, rather they belong to the first person who makes beneficial use of the water. An appropriator maintains the right to continue using the water without interference by later appropriators. However, the right is retained only as long as the water is used for benefit. The popular phrase "use it or lose it" was often connected to the appropriative water system.

During early western settlement, Congress permitted the states to control, distribute, and manage water on the public lands. The public could appropriate the water in accordance with state law. Through the second half of the nineteenth century, settlement and development of public lands occurred under various federal land laws, such as the Homestead Act of 1862 which opened the public lands to settlement. In 1877, the Desert Land Act opened all previously unappropriated, "surplus," water on the public lands for "use of the public for irrigation, mining and manufacturing purposes subject to existing rights." The act designated the states to regulate this appropriation of surplus water, but left the door open for the federal government to later assert water rights. Later, the federal government began to take a more active role with inception of land reclamation and flood control projects, assertion of Native American rights, and development of interstate agreements.