Navigational Servitude

Riparian rights in "navigable waters" are subordinate to the public's common right of navigation. This is called a "navigational servitude." Structures placed within or over navigable waters by riparian owners are subject to blockage by public works and uncompensated removal if determined to cause an obstruction to navigation.

The navigational servitude is specific to legitimate purposes of protecting and improving public navigation and does not extend to other matters, even those pertaining to the Commerce Clause.

The Commerce Clause extends to keeping clear the water channels of interstate and foreign commerce, as well as to the power to improve and enlarge their navigational capacity. The riparian navigational servitude extends to the bed of a public navigable waterbody, defined as the area of the channel below "high water mark" or the level of bank adequate to contain the flow at its average and mean stage suring the entire year. It does not extend above the "high water mark." Navigational improvements that result in increases in flow that damage riparian structures within the bed of a navigable waterbody are not subject to compensation. Riparians on non-navigable waterbodys, who hold title to the thread of the stream, are not subject to a navigational servitude and damages ocurring to their property as a result of improvements are compensable.

Although Admiralty law may apply to an artificially constructed canal used for the purposes of navigation, where title to the bed of the channel is privately held, it is not subject to a public navigational servitude.