Arizona v. California
Headline: Approves supplemental decree updating annual water allocations, priority dates, and a boundary exception for the Colorado River and Fort Mojave Indian Reservations, and keeps prior decrees in force while retaining Court oversight.
Holding: The Court approved and entered the Special Master’s supplemental decree amending prior decrees to set specific annual water allocations, consumptive-use irrigation amounts, priority dates, a California boundary exception, and retained jurisdiction.
- Sets fixed annual water allocations and irrigation acreages for two Indian reservations.
- Establishes priority dates for reservation water rights tied to historical reservation dates.
- Adds a California boundary exception and preserves earlier decrees while keeping court oversight.
Summary
Background
The Special Master submitted a proposed supplemental decree to carry the parties’ accords into effect; that proposed decree was reproduced as an appendix to the Court’s June 19, 2000 opinion and no objections were filed. The Court therefore approved and entered the supplemental decree. The amendments modify parts of the Decree of March 9, 1964 and the supplemental decrees of January 9, 1979 and April 16, 1984 as they relate to the Colorado River and Fort Mojave Indian Reservations.
Reasoning
The central question was whether to approve and enter the Special Master’s proposed supplemental decree. Because no objections were filed with the Clerk, the Court entered the proposed terms. The decree amends the Decree’s articles to set specific annual diversion limits and alternative consumptive-use amounts tied to irrigation acreage for the Colorado River Reservation (either 719,248 acre-feet or water for 107,903 acres) and for the Fort Mojave Reservation (either 132,789 acre-feet or water for 20,544 acres), and it lists priority dates connected to historical reservation actions. The decree also adds a stated exception concerning the western boundaries in California, updates acreage listings, and preserves other provisions of the earlier decrees.
Real world impact
The order fixes how much water those two reservations may divert each year and ties those amounts to irrigation needs and historical priority dates, affecting tribal water planning and state water management along the river. The Court expressly retains jurisdiction to order further proceedings and enter additional supplemental decrees, so these terms may be revisited if needed.
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