A canal is a long, narrow stretch of water that has been specially built, usually to enable barges or ships to sail inland.

1. In summer, boat trips go east down the canal to Regent s Park.
2. …the construction of a canal linking the Pacific and Atlantic oceans.

A channel is a route in the sea or in a large river along which ships can sail.

3. The Russian tankers finding their way up the channel occasionally todgefast.
4. The main channels had been closed by enemy submarines.

A channel is also a small passage along which water can flow.

5. The river had now assumed a new character, racing through a single channel between tree-clad banks.
6. …Irrigation channels.