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.
 
Vessels using waterways vary from small animal-drawn barges to immense ocean tankers and ocean liners[?], such as cruise ships[?].
At one time, canals were built mostly for small wooden barges drawn by horses or other draft animals.  Today, major canals are built to allow passage of large ocean-going vessels. See Ship Canal.
Also see:
 
All Wikipedia text 
is available under the 
terms of the GNU Free Documentation License