Arizona v. California

1983-03-30

Headline: Colorado River water dispute: Court bars relitigation of 1964 irrigation acreage, allows tribes to join case, and limits water increases to lands finally fixed by court rulings, protecting state water allocations.

Holding: The Court held that tribes may intervene but the 1964 irrigable-acreage determinations may not be relitigated now, and only boundaries finally fixed by judicial decrees — not secretarial orders — can support added tribal water rights.

Real World Impact:

Allows tribes to intervene and participate directly in water adjudication.
Prevents reopening the 1964 irrigable-acreage calculations for new water awards.
Limits increases to tribal water only for lands fixed by court judgments.

Topics: water rights, Indian reservation water, Colorado River allocations, reservation boundaries

Summary

Background

Five Indian tribes, joined by the United States, sought larger water rights from the Colorado River than those fixed in a 1964 decree. Arizona, California, Nevada, and several California water agencies defended the earlier allocation. The 1964 decision measured tribal rights by the amount of practicably irrigable land on each reservation and left open adjustments if reservation boundaries were later finally determined.

Reasoning

The Court first allowed the tribes to intervene and proceed in the case. It then held that the earlier irrigable-acreage calculations should not be reopened now because the decree’s finality and the need for reliable water planning outweigh reopening long-settled factual issues. The Court refused to treat unilateral secretarial orders as “final determinations” of reservation boundaries. However, it accepted that judicial decrees that have already fixed certain lands as reservation territory may justify limited increases in tribal water rights.

Real world impact

Practically, tribes can participate in these proceedings but cannot relitigate the basic acreage calculations from 1964. Only lands that have been confirmed as reservation land by courts can increase a tribe’s water allotment now. The Court directed the parties to prepare a proposed decree reflecting these limits and noted that related boundary litigation in a lower court should proceed.

Dissents or concurrances

Justice Brennan (joined by Justices Blackmun and Stevens) disagreed with barring reconsideration and would have reopened the acreage issue and approved the Special Master’s conditional approach to boundary lands, citing possible injustice to the tribes.