Summary of the Big Horn River Adjudication


On January 22, 1977, Wyoming enacted statute § 1-37-106, which authorized the State to institute an action to determine the nature, extent, and relative priority of water rights of all persons in any river system. On January 24, 1977, the State filed its complaint against the United States and other parties to adjudicate all water rights in Water Division 3 including reserved water right claims for the Wind River Indian Reservation. The Eastern Shoshone and Northern Arapaho tribes intervened and joined the federal government as defendants in the Big Horn General Stream Adjudication.

The treaty between the U.S. government and the Bannock and Shoshone Indians established the Wind River Reservation on July 3, 1868. The Bannock later ceded land back to the U.S. and the Arapaho then moved to the reservation. Reviewing the decree of the District Court, the Wyoming Supreme Court in Big Horn I (1988) examined the Second Treaty of Fort Bridger and found that Congress intended to reserve water for the Tribes’ agricultural use on the reservation. The Tribes’ were awarded a 499,862 acre-foot reserved water right with a treaty priority date of July 3, 1868, for the 107,976 “practicably irrigable acres” on the reservation. The Court also held that Indian and non-Indian successors of Indian allottees were entitled to treaty based water rights for the practically irrigable acres they could prove were continuously irrigated since or within a reasonable time after the property passed out of Indian ownership (“Walton Rights”). The Wyoming Court’s decision was affirmed by the U.S. Supreme Court in Wyoming v. United States, 492 U.S. 406 (1989).

There have been six other matters appealed to the Wyoming Supreme Court during the course of this adjudication. The following briefly describes the six subsequent Wyoming Supreme Court cases that followed Big Horn I:

  • In Big Horn II, the Court upheld treaty priority rights for Indian and non-Indian successors of Indian allottees (“Walton Rights”) to the extent the claimants could demonstrate the amount irrigated by their Indian predecessors or within a reasonable after passing our of Indian ownership.
  • In Big Horn III, the Court ruled that the Tribes could use their water rights solely for agricultural purposes, and that the State Engineer had administrative authority over all water rights in the State but must turn to the courts if the Tribes violate the decree.
  • In Big Horn IV, the Court required that all Walton claims to be fully adjudicated in the District Court before the Supreme Court would review an appeal on such claims.
  • Big Horn V imposed limitations on Walton claims, holding that certain claims (“Super Waltons”) were not entitled to the treaty priority date for lands originally part of the Wind River Indian Reservation whose title derived from federal law, but not from Indian allottees.
  • Big Horn VI provided that the Walton Right holders, like the Tribes, must seek administration by the State Engineer first, before turning to the courts for enforcement of their rights, if necessary.
  • Big Horn VII held that the court does not have authority to settle private contract disputes between water users and the Bureau of Reclamation within the scope of the general adjudication.

For more information, please select from the list below:

Basin Issue Summary:

2003 Wind/Bighorn River Basin Plan:

Wyoming State Engineer's Office
Herschler Building, 1st Floor West 122
West 25th Street
Cheyenne, WY 82002
Phone No. - 307-777-6150

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