upper course also called youthful stage by W.M. Davis
V-shaped valleys typically include rapids and waterfalls. These valleys are formed by fast-flowing rivers eroding downwards into the landscape, resulting in steep sides and features like rapids and waterfalls due to the force of the moving water.
V shaped valleys, meanders, oxbow lakes, gorges, waterfalls rapids & deltas are some.
No, the Niger River does not have any major waterfalls. It flows through West Africa for about 2,600 miles before emptying into the Gulf of Guinea. The river landscape mainly consists of plains, valleys, and rapids rather than waterfalls.
Rapids
cataract
V-shaped valleys The river channel - vertical erosion, shallow but a very fast flow Waterfalls Gorges(which are formed by waterfalls) Bedload is also very big and angular.
You could say καταρράκτες [=waterfalls]
Waterfalls or river rapids
A lock is the mechanism for raising and lowering ships in a river that has rapids or waterfalls. Locks are used to make navigation an easier task.
A mechanism for raising or lowering ships in a river that has rapids or waterfalls is called dam and lock system. It is a special kind of dam system.
Portage.
CAtaract