No, the area drained by a river is a river basin or drainage basin. The flood plain is in the lower valley reaches, where heavy rain can cause the river to flood, often bursting over flood defences, and for the water to flood over a large area.
An area drained by a river or river system is called a drainage basin.
A 'flood plain' usually.
A river basin is an area of land drained by a river and its tributaries.
It's called a 'flood plain'.
River bank, flood plain, water meadow.
Flood plain
The narrow strip of land on both sides of the rivers is called cover flood plains
The part of a river that is underwater when the river overflows its banks is called the flood plain.
It is called the flood plain.
It is referred to as the Flood Plain.
The flood plain. Delta
Flood plain.