## Facts

- New Mexico initiated a general stream adjudication to determine all rights to water from the Rio Mimbres, a stream originating in the Gila National Forest and flowing downstream through private lands used for irrigation and mining.
- The United States asserted implied federal reserved water rights for the Gila National Forest, claiming instream flows for recreation, aesthetics, wildlife preservation, and stockwatering, as well as water needed to protect forest resources and water flows.
- The Gila National Forest was established under the Organic Administration Act of 1897, which states purposes including improving and protecting the forest, securing favorable conditions of water flows, and furnishing a continuous supply of timber.
- Congress later enacted the Multiple-Use Sustained-Yield Act of 1960, directing administration of national forests for multiple uses (including outdoor recreation, range, watershed, and wildlife and fish) while stating it was supplemental to, and not in derogation of, the 1897 purposes.
- The state trial court and the New Mexico Supreme Court rejected most of the United States’ claimed reserved rights, concluding the 1897 Act did not include the asserted instream-flow purposes and that the 1960 Act did not enlarge reserved rights for preexisting forests.

## Issues

1. Whether the implied-reservation doctrine reserved Rio Mimbres water for recreation, aesthetics, wildlife preservation, and stockwatering when the Gila National Forest was created under the Organic Administration Act of 1897.
2. Whether the Multiple-Use Sustained-Yield Act of 1960 enlarged the purposes of previously created national forests so as to create additional implied reserved water rights.

## Decision

- The Supreme Court affirmed the judgment of the New Mexico Supreme Court.
- The Court held that implied reserved water rights for national forests established under the 1897 Act extend only to water necessary to fulfill the Act’s primary purposes: preserving timber resources and securing favorable conditions of water flows.
- The Court rejected reserved-rights claims for recreation, aesthetics, wildlife preservation, and stockwatering as not being primary purposes of the 1897 forest reservation.
- The Court held that the Multiple-Use Sustained-Yield Act did not retroactively create or enlarge implied reserved water rights for forests previously established under the 1897 Act.
- Water for uses beyond the reservation’s primary purposes must be acquired under state water law.

## Legal Principles

- Implied federal reserved water rights exist only when water is necessary to accomplish the specific purposes for which federal land is reserved; the doctrine is a limited exception to Congress’s general deference to state water law.
- Courts must identify the reservation’s primary purposes from the reserving instrument; implied rights do not arise for secondary or indirect uses of the reservation.
- For national forests created under the Organic Administration Act of 1897, the relevant primary purposes are forest protection (including timber) and securing favorable conditions of water flows.
- Later statutes broadening federal land management objectives do not, without clear congressional direction, retroactively expand implied reserved water rights created by earlier reservations.
- Where the federal government seeks water for uses not within the reservation’s primary purposes, it must obtain those rights under applicable state prior-appropriation rules.

## Conclusion

The Court limited federal reserved water rights in national forests to the minimum water necessary to serve the 1897 Act’s primary purposes and required the United States to rely on state law for additional water sought for recreation, wildlife, aesthetics, or stockwatering, with the 1960 multiple-use statute not expanding earlier implied reservations.


United States v. New Mexico, 438 U.S. 696 (1978)