Flowing water is one of the most significant and visually striking forces of erosion. Rivers transport a great amount of rock material into the sea.

Young rivers flow at great speeds. As a result of this, they cause a lot erosion at the bottom of the riverbed. The flowing force of a young river can even move large boulders downstream.

Young and fast-flowing rivers are mostly found in mountainous regions. In these areas, the swift river has often eroded its channel into a steep V-valley.

Over the course of millennia, rivers can also form deep canyons.