Rivers, streams, estuaries, and canals are flowing waters with a slow flow to high flow. Running water has a predisposition to sustain life by enhancing biodiversity, helping water control, providing cheap and effective transport, and enabling many recreational, cultural, and social activities.

The river is natural water that runs true valley or well-defined, they have a permanent path, unlike stream that has a temporary path, and oftentimes it doesn’t run true valley. Canals on the other hand are man-made structures to manage incoming water in urban areas.