Question

How does running water carry out its work?

Answer 1

The energy that makes running water move comes from gravity. As water flows downslope from a higher to a lower elevation, the gravitational potential energy stored in water transforms into kinetic energy. About 3% of this energy goes into the work of eroding the walls and beds of stream channels. Running water causes erosion in four ways:

Scouring: Running water can remove loose fragments of sediment, a process called scouring. Breaking and lifting: In some cases, the push of flowing water can break chunks of solid rock off the channel floor or walls. In addition, the flow of a current over a clast can cause the clast to rise, or lift off the substrate. Abrasion: Clean water has little erosive effect, but sedimentladen water acts like sandpaper and grinds or rasps away at the channel floor and walls, a process called abrasion. In places where turbulence produces long-lived whirlpools, abrasion by sand or gravel carves a bowl-shaped depression, called a pothole, into the floor of the stream (figure below a, b). Dissolution: Running water dissolves soluble minerals as it passes, and carries the minerals away in solution. 

Answer 2

Running water can remove loose fragments of sediment, a process called scouring. Breaking and lifting: In some cases, the push of flowing water can break chunks of solid rock off the channel floor or walls. In addition, the flow of a current over a clast can cause the clast to rise, or lift off the substrate. Abrasion: Clean water has little erosive effect, but sedimentladen water acts like sandpaper and grinds or rasps away at the channel floor and walls, a process called abrasion. In places where turbulence produces long-lived whirlpools, abrasion by sand or gravel carves a bowl-shaped depression, called a pothole, into the floor of the stream (figure below a, b). Dissolution: Running water dissolves soluble minerals as it passes, and carries the minerals away in solution.