Wyoming's Big Horn General Stream Adjudication

Abstract

The State of Wyoming’s general stream adjudication in the Wind/Big Horn Basin (“Big Horn” adjudication) effectively concluded in September 2014 after thirty-seven years. Lengthy, costly, and often contentious, this proceeding addressed diverse water rights claims submitted by over 20,000 parties. Perhaps most notable were claims for reserved rights asserted by the Eastern Shoshone and Northern Arapaho tribes on the Wind River Indian Reservation — claims that when considered by the U.S. Supreme Court in Wyoming v. United States raised salient issues regarding the practicably irrigable acreage (PIA) standard and related sensitivity doctrine then espoused by certain members of the Court. Drawing mainly on primary sources in a digital archive created for the Big Horn adjudication, this Article offers a comprehensive survey of the proceeding. It initially situates the adjudication within the Wind/Big Horn Basin and the jurisprudential backdrop of western water law, and it subsequently chronicles the adjudication’s three distinct yet interconnected phases. The narrative offers many insights into the composition of general stream adjudications and their relative value as mechanisms for resolving claims of federal, state, and tribal sovereigns to water resources. Also illuminated is the precedent set by the adjudication for water allocation and management within the Wind/Big Horn Basin — a precedent it is hoped will foster collaboration and innovation in the future.

Keywords: water law, water policy, water rights, general stream adjudications, American Indians, Native Americans, reserved rights, Walton rights, prior appropriation, McCarran Amendment