US SUPREME COURT DECISIONS

This extended litigation over rights to the waters of the Colorado River began in 1952, when Arizona brought an original action in this Court against California and several of its public agencies. Later, Nevada, New Mexico, Utah, and the United States became parties. Following the report of a Special Master, the major issue in the case -- the apportionment of water among the lower basin States -- was resolved in the Court's opinion, 373 U. S. 373 U.S. 546, and 1964 decree, 376 U. S. 376 U.S. 340. A supplemental decree identifying present perfected rights was entered in 1979. 439 U. S. 439 U.S. 419. Pursuant to the Court's initial opinion and decree, the United States acquired water rights for the reservations of five Indian Tribes that are dependent upon the river for their water. The proper standard for measuring the water rights intended for the reservations was held to be "practicably irrigable acreage," and the Special Master's calculation of the amount of such acreage was approved. The United States, and the Tribes which ask to intervene in the action, now seek to have those water rights increased to account for (1) "omitted lands" -- irrigable lands within recognized reservation boundaries for which water rights were not claimed in the earlier litigation; and (2) "boundary lands" -- irrigable lands claimed to now have been finally determined to lie within the reservations. A Special Master appointed by the Court issued a preliminary finding allowing the Tribes to intervene and a final report concluding that the Tribes are entitled to the additional rights.

Held:

1. The Indian Tribes' motions to intervene are granted. Since the Tribes do not seek to bring new claims or issues against the States, but only ask leave to participate in an adjudication of their water rights that was commenced by the United States, this Court's judicial power over the controversy is not enlarged by granting leave to intervene, and the States' sovereign immunity protected by the Eleventh Amendment is not compromised. Moreover, the Tribes satisfy the standards for permissive intervention set forth in the Federal Rules of Civil Procedure, which serve as a guide in an original action in this Court. Pp. 460 U. S. 613-615.

2. The States' exceptions to the Special Master's conclusion that the Tribes are entitled to increased water rights for omitted lands are sustained. chanrobles.com-red

Page 460 U. S. 606

The prior determination of Indian water rights in the 1964 decree precludes relitigation of the irrigable acreage issue. Article IX of the 1964 decree -- which provided that this Court would retain jurisdiction of the action

"for the purpose of any order, direction, or modification of the decree, or any supplementary decree, that may at any time be deemed proper in relation to the subject matter in controversy"

-- must be subject to the general principles of finality and repose, absent changed circumstances or unforeseen issues not previously litigated. The principles of res judicata advise against reopening the calculation of the amount of practicably irrigable acreage to which the Tribes are entitled. To apply the law-of-the-case doctrine in this Court's original actions, as the Special Master would here, would weaken the finality of the decrees in such actions, particularly in a case such as this one, which turns on statutory, rather than Court-fashioned, equitable criteria. Recalculating the amount of practicably irrigable acreage runs directly counter to the strong interests in finality in this litigation, a major purpose of which has been to provide the necessary assurance to the States and various private interests involved of the amount of water they can anticipate receiving from the Colorado River. Article IX did not contemplate a departure from these fundamental principles so as to permit retrial of factual or legal issues that were fully and fairly litigated 20 years ago. The absence of the Indian Tribes in the prior proceedings does not require relitigation of their reserved rights. Pp. 460 U. S. 615-628.

3. The States' and state agencies' exceptions to the Special Master's finding that certain reservation boundaries extended by order of the Secretary of the Interior have been "finally determined" within the meaning of Article II(D)(5) of the 1964 decree -- which provided that the quantities of water fixed in the provisions of the decree setting forth the reservations' water rights in the Colorado River shall be subject to appropriate adjustment by agreement or decree of this Court in the event "the boundaries of the respective reservations are finally determined" -- are sustained. But with respect to the boundaries determined by judicial decree in certain quiet title actions, the exceptions are overruled, and the Special Master's conclusion that these boundaries were "finally determined" within the meaning of Article II(D)(5) is adopted. Accordingly, the 1979 supplemental decree in this case should be amended to provide to the respective reservations appropriate water rights to service the irrigable acreage the Special Master found to be contained within the tracts adjudicated by the specified quiet title judgments to be reservation land. Pp. 460 U. S. 628-641.

Exceptions to the Special Master's Report sustained in part and overruled in part, and motions to intervene granted. chanrobles.com-red

Page 460 U. S. 607