waterway

n. channel or way for water; navigable body of water (river, channel, etc.)

A waterway is any navigable body of water. These include rivers, lakes, oceans, and canals. In order for a waterway to be navigable, it must meet several criteria:The waterway must be deep enough to allow the draft depth of the vessels using it;The waterway must be wide enough to allow passage for the beam width of the vessels using it;The waterway must be free of barriers to navigation such as waterfalls and rapids, or have a way around them (such as canal locks);The current of the waterway must be mild enough to allow vessels to make headway.
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Noun
1. a navigable body of water
(hypernym) body of water, water
(hyponym) ditch
2. a conduit through which water flows
(synonym) watercourse
(hypernym) way
(hyponym) canal

(n.)
Heavy plank or timber extending fore and aft the whole length of a vessel's deck at the line of junction with the sides, forming a channel to the scuppers, which are cut through it. In iron vessels the waterway is variously constructed.
  

River, canal, lake or other stretch of water that by natural or man-made features is suitable for navigation. (DOE5)

See also Water.