What name is given to the area drained by a river and its tributaries?

The term used to describe the area drained by a river and its tributaries is known as the drainage basin. A drainage basin is essentially the entire land area from which water collects and flows into a specific river or set of rivers. This includes all the streams, lakes, and other bodies of water that contribute to the river's flow.

This concept is vital in understanding the hydrological cycle, river management, and environmental studies. The drainage basin is significant as it helps assess water resources, manage floods, and understand ecosystems within its boundaries. Students learn that it encompasses both the river itself and all its tributaries, highlighting its comprehensive nature when examining river systems.

While other terms like watershed, floodplain, and catchment area may relate to rivers and water, they have distinct meanings and are used in specific contexts within geography. A watershed refers more specifically to the line across elevated land that separates different drainage basins, while a floodplain is the area adjacent to a river that may be prone to flooding. Catchment area often overlaps with drainage basin but can refer to a smaller specific local area where water collects. Thus, drainage basin accurately represents the entirety of the area influenced by a river and its tributaries.