In re the General Adjudication of All Rights to Use Water in the Big Horn River System (Big Horn I)
Wyoming Supreme Court
753 P.2d 76 (1988)
Wyoming (plaintiff) brought a system-wide water-rights adjudication covering the Wind River Indian Reservation, created under an 1868 treaty emphasizing agricultural development; a special master recommended reserved water rights not just for irrigation but also for fisheries, wildlife, aesthetics, minerals, and other uses, but the water judge approved reserved rights only for practicably irrigable acreage (PIA) and rejected all non-agricultural uses, prompting appeals from multiple parties.
Does an Indian reservation created primarily for agricultural purposes have implied water rights only for agricultural and subsumed uses in the amount necessary to irrigate the reservation's practicably irrigable acreage?