Navigability and its Consequences: State Title, Mineral Rights, and the Public Trust Doctrine

“Navigability” and “navigable waters” are two of the most complex terms of art in American law because their meanings vary from context to context. A “navigable water” for purposes of the federal courts’ admiralty jurisdiction is not precisely the same thing as a “navigable water” for Commerce Clause purposes, and the Commerce Clause definition can be further refined in statute like the federal Clean Water Act. Other important federal law definitions of navigability govern state title to banks and beds of waterways and the scope of the federal navigation servitude. As this article will discuss, these tests overlap considerably, and attempts to distinguish them can cause confusion. State law definitions of “navigability” for state regulatory purposes complicate the multiple valences of “navigable water” even further.

This article provides an overview of some of the more important definitions of “navigability” and “navigable waters.” In general, labeling a waterway as “navigable” signals that either the federal government or the public acquires some right to the waterway in question. However, if the waterway also meets the “navigable water” test for state title, complicated legal relationships among the federal government, the relevant state, the general public, and private riparian landowners almost inevitably follow.