## Facts

- Congress authorized the Denison Dam and Reservoir Project on the Red River at the Texas–Oklahoma line as part of a broader flood-control and navigation program for the Mississippi River system.
- The project sought to regulate streamflow, reduce damaging floods, improve navigation on navigable stretches of the Red River, and generate hydroelectric power to offset project costs.
- Oklahoma alleged the dam would rest largely on Oklahoma soil and create a reservoir inundating about 150,000 acres, including roughly 100,000 acres in Oklahoma.
- The state asserted it owned about 3,800 acres in the basin (used for schools, a prison farm, highways, and rights-of-way) and that about 8,000 residents would be displaced.
- Oklahoma alleged major harm to oil-and-gas-bearing lands and a severe reduction of local ad valorem tax bases, impairing school districts and other local governmental units’ ability to meet bonded obligations.
- Oklahoma sought to enjoin construction and to restrain condemnation proceedings in Oklahoma courts to acquire land for the project.
- A three-judge federal district court upheld the statute and denied injunctive relief; Oklahoma appealed directly to the U.S. Supreme Court.

## Issues

1. Whether Congress may authorize a dam and reservoir affecting nonnavigable reaches within a state when the project is part of a comprehensive flood-control and navigation plan for a navigable river system.
2. Whether Congress’s commerce power permits federal flood control, flow regulation, and related works despite significant state property interests and alleged disruption to local tax bases and governmental functions.
3. Whether inclusion of hydroelectric power generation, which increased the dam’s height and the reservoir’s area, exceeded Congress’s commerce power.

## Decision

- The Supreme Court affirmed the denial of an injunction and upheld the statute authorizing the Denison Dam and Reservoir.
- The Court held the project was a valid exercise of the commerce power as part of an integrated flood-control and navigation program.
- The Court held Congress may control nonnavigable portions of a river and its tributaries when necessary to preserve and promote commerce on navigable portions.
- The Court held the hydroelectric power component did not invalidate the project where power generation was interrelated with flood control and flow regulation.

## Legal Principles

- Congress’s commerce power over navigable waters is not diminished because particular portions are not presently used for commerce.
- Congress may regulate nonnavigable reaches and tributaries to protect navigable waters and interstate commerce, including by controlling floodwaters.
- Congress may regulate intrastate activities and agencies that affect interstate commerce when such control is appropriate and needful.
- Whether a particular flood-control or navigation project will sufficiently benefit interstate commerce to justify federal action is for Congress, not the courts; courts do not conduct cost-benefit review of the legislative choice.
- A multipurpose federal water project does not become unconstitutional because it also serves additional ends (including hydroelectric power) where the project is grounded in legitimate commerce-related objectives.

## Conclusion

The Court sustained federal authority to construct a multipurpose dam and reservoir as part of a comprehensive navigation and flood-control plan, holding that Congress may regulate nonnavigable reaches and tributaries affecting navigable waters and may include interrelated hydroelectric features, notwithstanding substantial state and local impacts.


Oklahoma ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508 (1941)