## Facts

- Twin City Power Co. assembled roughly 4,700 acres of “fast land” above the ordinary high-water mark along the Savannah River for a planned hydroelectric project.
- The United States initiated condemnation proceedings to acquire portions of that land for the Clark Hill Project on the Savannah River.
- Congress authorized the Clark Hill Project as part of comprehensive development of the Savannah River Basin for flood control and other purposes, including improving navigation and generating hydroelectric power.
- The government valued the land based on agricultural and timber uses, excluding any increment tied to hydroelectric-site potential.
- The district court, and then the court of appeals, included power-site value in the award on the view that the taking’s primary purpose was not navigation.
- The Supreme Court granted review and addressed whether the Fifth Amendment requires payment for value attributable to the “water power in the flow of the stream.”

## Issues

1. Whether just compensation for condemnation of fast land bordering a navigable river must include an increment of value based on the site’s hydroelectric potential derived from the river’s flow.
2. Whether courts may treat navigation as merely incidental to a congressionally authorized multipurpose river project when determining compensable elements of value.
3. Whether state-recognized water-related interests can require the United States to pay for water-power value in a federal navigation-related taking.

## Decision

- The Supreme Court reversed the court of appeals in a 5–4 decision.
- Just compensation did not include any element of value attributable to the stream’s water-power potential.
- Courts could not recharacterize Congress’s authorization to treat the project as essentially a power-development taking for valuation purposes.
- The federal government’s dominant Commerce Clause interest in navigable waters barred requiring payment for value rooted in the flow of the navigable stream, even when the condemned land lay above the high-water mark.

## Legal Principles

- When Congress authorizes a project serving navigation on a navigable river, courts must accept that navigation purpose and may not substitute their own assessment of the project’s “primary” objective for valuation.
- If navigation interests are served, it is constitutionally irrelevant that the project also advances other objectives (e.g., flood control or hydroelectric generation) for purposes of determining compensable value.
- The United States holds a dominant servitude over navigable waters under the Commerce Clause; this permits assertion of federal control over the stream’s flow to the exclusion of conflicting private claims.
- In condemnation of fast land adjacent to a navigable river for a navigation-serving project, the Fifth Amendment does not require compensation for any increment reflecting “water power in the flow of the stream,” even if the parcel is a favorable dam site.
- State law cannot create a compensable property interest against the United States in the water-power value of a navigable stream’s flow.
- Just compensation measures the owner’s loss, not the government’s gain; requiring payment for public control of navigable-water power would improperly create private claims in a public domain resource.

## Conclusion

The Court held that when the United States condemns fast land bordering a navigable river for a congressionally authorized project that serves navigation, the compensation owed excludes any added value derived from the river’s hydroelectric power potential, notwithstanding mixed project purposes or state-recognized water-related interests.


United States v. Twin City Power Co., 350 U.S. 222 (1956)