What is the law of the colorado river?
The Law of the River is a compilation of compacts, acts, guidelines, minutes, and records of decisions. The main laws are listed below.
Colorado River Compact: In 1922, the Compact was negotiated by the seven basin states (WY, UT, CO, NM, NV, CA, & AZ) and the federal government (Tribes and Mexico were not involved in negotiations). Under the Compact, the states established a framework for apportionment of the water supplies between the Upper Basin and the Lower Basin. The dividing line between the two basins is at Lees Ferry, AZ. The Upper Basin and Lower Basin were each apportioned 7.5 million acre-feet (MAF) annually for beneficial consumptive use. Read More.
Boulder Canyon Act: In 1928, Congress approved this Act which allocated the Lower Basin States’ water rights. The Act states that a fair division of the first 7.5 MAF of such mainstream waters would give 4.4 MAF annually to California, 2.8 MAF annually to Arizona, and 300,000 AFY to Nevada. However, Congress intended to apportion only the mainstream, leaving to each State their own tributaries. Read More.
Upper Colorado River Basin Compact: In 1948, this Compact was adopted to provide equitable division and apportionment of the Upper Basin. Unlike the Lower Basin, Upper Basin water allocations are based on hydrology and percentages: NM (11.25%), WY (14%), CO (51.75%), and UT (23%). The only state in the Upper Basin with a fixed amount is Arizona (50,000 AFY). Tribal water rights were recognized in the Compact; Article XIX states “(a) Nothing in this compact shall be construed as affecting the obligations of the United States of America to Indian Tribes.” Read More.
Additional Information on Key Court Decisions Regarding Tribal Water Rights: