- In simple terms, drainage describes the river system of a particular region.
- Small streams flow in different directions and converge to form the main river , draining into a large body of water, such as a lake, sea, or ocean.
- A drainage basin is an area drained by a single river system.
- An elevated area, such as a mountain or upland, separates two drainage basins .
- Such uplands are called water divide.
- Amazon basin is the world’s largest drainage basin.
- The Ganga basin is the largest drainage basin in India.