Channel Thalweg

The thalweg is the line connecting the deepest points along a channel, river, or strait, the locus of greatest depth down the watercourse. In hydrography it is the natural deep-water track a vessel follows and the line dredged channels are aligned to. The thalweg usually carries the strongest flow and the coarsest bed load, and it migrates as the channel scours and shifts. In international law the thalweg of a navigable boundary river often defines the median line between states. Charted least depths along the thalweg set the controlling depth for navigation and under-keel clearance planning.