drainage basin
nounUK /ˈdreɪnɪdʒ ˌbeɪsn/
US /ˈdreɪnɪdʒ ˌbeɪsn/
A drainage basin is all the land where rain and rivers flow down to the same low spot.
The river carries water from the whole drainage basin to the sea.
OTHER MEANINGS
2. The entire land area that collects and drains water into a single river system.
Scientists mapped the drainage basin to study how pollution spreads downstream.
3. A region bounded by high ground that separates it from neighboring river systems.
The mountains form the edge of the drainage basin.
4. In geology, the area supplying sediment and water to a lake or closed depression.
The desert lake sits in a drainage basin with no outlet to the ocean.