old river
Flood plain
It is called the flood plain.
The floodplain is an area of flat land found on either side of a river that usually becomes wider as the river nears its mouth. A low watery formation of land at the mouth of a river is called a delta.
The flat, wide area along a river is called its flood plain. This is sometimes part of a larger area called the alluvial plain, which formed as the river shifted over time and deposited soil when it flooded.
It's called a 'flood plain'.
Flood plain
Euphrates river and Tigres river
Mesopotamia was located on flat plain between the Tigris and Euphrates rivers.
The flat, wide area along a river is called its flood plain. This is sometimes part of a larger area called the alluvial plain, which formed as the river shifted over time and deposited soil when it flooded.
Geographically, a "plain" is a large, treeless area of level or nearly level land. By convention the term "plain" is usually used to describe a low level flat area such as a coastal plain, sea floor plain, a river plain or a lunar plain (mare) rather than an elevated flat area which would be called a plateau.
Flat open land is called a plain. A plain is a flat area with few trees. They can occur as lowlands and at the bottom of valleys, but can also be on plateaus or uplands at high elevations.
A large piece of flat land is called a plain. A mountain desert refers to a desert area with significant mountainous terrain.