## Facts

- The Pyramid Lake Paiute Tribe’s reservation includes Pyramid Lake in Nevada, a lake historically central to the Tribe’s subsistence and fishery.
- Pyramid Lake depends on inflow from the Truckee River; upstream diversions for irrigation reduced inflows and threatened the lake’s level and fish habitat.
- The Truckee–Carson Irrigation District (TCID) is a federal reclamation irrigation project in Nevada that receives Truckee River water under federal contracts and Interior administration.
- On September 14, 1972, the Secretary of the Interior issued a regulation (effective November 1, 1972) setting the basis for allocating Truckee River water to TCID for the next twelve months.
- The Tribe sued under the Administrative Procedure Act (APA), seeking to set aside the regulation as arbitrary, capricious, and beyond the Secretary’s authority, and seeking declaratory and injunctive relief for allegedly withheld or unreasonably delayed agency action.
- The Tribe alleged the regulation over-delivered water to TCID beyond what governing decrees and statutes allowed, failed to determine TCID’s lawful entitlement, tolerated wasteful irrigation practices, and insufficiently protected tribal trust resources.

## Issues

1. Whether the Secretary’s water-allocation regulation was final agency action reviewable under the APA.
2. Whether the regulation was arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law under APA § 706(2).
3. Whether the Secretary’s allocation improperly exceeded limits imposed by applicable court decrees and federal statutes governing Truckee River water deliveries.
4. Whether the Secretary breached fiduciary obligations to protect tribal resources by approving allocations that failed to prevent waste and impaired Pyramid Lake and the Tribe’s interests.
5. Whether the Secretary unlawfully withheld or unreasonably delayed required actions under APA § 706(1) to bring deliveries and project operations into conformity with law and trust obligations.

## Decision

- The court held the Tribe was an aggrieved party; the dispute was ripe; administrative remedies were exhausted; and the Secretary’s action was final and reviewable under the APA.
- The court set aside the 1972 regulation as unlawful because it was arbitrary, capricious, and an abuse of discretion.
- The court found the Secretary did not provide an adequate, reasoned basis for the quantity of water allocated to TCID and did not sufficiently account for legal constraints on deliveries.
- The court concluded the Secretary failed to meet trust responsibilities to the Tribe by not acting affirmatively to protect tribal resources and by tolerating wasteful project practices.
- The court ordered reconsideration and revision of the allocation approach consistent with governing decrees and statutes, the duty to prevent waste, and fiduciary obligations to the Tribe and Pyramid Lake.

## Legal Principles

- Final agency regulations that directly affect a regulated party’s interests are reviewable under the APA when the controversy is ripe and administrative remedies are exhausted.
- Under APA § 706(2)(A), an agency action is unlawful if it lacks a reasoned explanation grounded in the record and relevant legal constraints, making it arbitrary or capricious.
- When administering federal reclamation water deliveries, the Secretary must conform allocations to applicable statutes and controlling decrees and may not justify allocations by unsupported judgment.
- The United States’ trust relationship with tribes imposes affirmative duties on Interior to protect tribal resources when making competing resource-allocation decisions.
- The Secretary has authority and responsibility to address and prevent waste in reclamation project water use where waste diminishes legally protected interests, including tribal resources.
- Under APA § 706(1), courts may compel agency action unlawfully withheld or unreasonably delayed, particularly where statutory and trust responsibilities require timely enforcement and management decisions.

## Conclusion

The court invalidated Interior’s one-year Truckee River allocation regulation for TCID because it was not supported by a reasoned, lawful determination of need and failed to reflect the Secretary’s obligations to comply with governing legal limits, prevent waste, and protect tribal trust resources tied to Pyramid Lake.


Pyramid Lake Paiute Tribe of Indians v. Morton, 354 F. Supp. 252 (D.D.C. 1972)