A body of water, such as a
river,
canal or
lake, is navigable if it is deep and wide enough for a vessel to pass and there are no obstructions, like
rocks,
trees and low
bridges. Shallow rivers may be made navigable by the installation of
locks that increase and regulate water depth. A very high water speed may also make a
channel unnavigable and high-
latitude waters may be unnavigable in winter because of
freezing. Navigability also depends on the size of the vessel: A small river may not be navigable by a
freighter, but it might be navigable by a smaller craft, like a
motor boat or
kayak. Therefore, whether a water body is considered navigable or unnavigable depends on the context.
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The waters of the United States, including the territorial sea and such waters as lakes, rivers, streams; waters which are used for recreation; and waters from which fish or shellfish are taken and sold in interstate or foreign commerce.
(49CFR171) (49CFR194)
Traditionally, waters sufficiently deep and wide for navigation by all, or specified vessels; such waters in the United States come under federal jurisdiction and are protected by certain provisions of the Clean Water Act.
Water usable, with or without improvements, as routes for commerce in the customary means of travel on water.