What is the difference between canals and rivers?

The main difference between a canal and a river is that a river is a natural flow of water while a canal is man-made. A river by definition flows from inland into the sea while a canal is most often constructed to connect existing rivers, lakes or oceans.

A river is a natural flow of water, while canals are man-made. Rivers also usually flow into bigger bodies of water, such as seas or oceans, while canals were built to connect rivers.