A body of water, such as a river, canal or lake,'s navigable if it's deep, wide and slow enough for a vessel to pass and there're 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, or by dredging. 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… (More on Navigability)