How are Waterfalls formed?
A waterfall is a river or a body of water that steeply falls over a rocky edge into a plunge pool. These are also called cascades. Know in the article below, how waterfalls are formed and all about the types of waterfalls here.
How are Waterfalls formed?
Erosion is the process of wearing away the earth. It plays an important part in the formation of waterfalls. Waterfalls also contribute to erosion.
The process of formation of waterfalls happens when a stream flows from soft rock to hard rock. This happens both laterally and vertically. In every case the soft rock erodes and leaves the hard rock as it is. Over this a stream falls.
The fall line is an imaginary line along which parallel rivers plunge while flowing from uplands to low lands. Many waterfalls in this way help the geologists determine a region's fall line and underlying rock structure.
As the stream flows it carries various amounts of sediments- be it microscopic silt, pebbles or boulders. Sediments erode the beds of soft rocks like sandstone or limestone. The stream then cuts the beds so deep that only hard rocks like granite are left.
Waterfalls develop as the granite formations form cliffs and ledges.
The stream's erosion increases near the base as velocity increases of the rivers. The movement of water at the top can erode the rocks to be flat and smooth. This way the plunge pool is formed at the base. The crashing flow also sometimes creates whirlpools that erode the plunge pool beneath them.
The erosion at the base of the waterfall causes the water to recede. The area behind the waterfall is worn away creating a hollow cave like structure that is called the rock shelter. The rocky ledge sends down tumbles and boulders into the stream bed and plunge pools. The waterfall erosion starts again breaking the boulders down of the previous left rocks.
The waterfalls may forma cross fault lines as well.
Types of Waterfalls
Block waterfall- It descends from a wide stream. Niagara Falls is an example of the same.
Cascade Waterfall- It is a waterfall that descends over a series of rock steps.This type of waterfall is safe enough for children to play in the water. Example- Monkey falls.
Cataract- It is a dangerous and powerful waterfall. Iguazu River on the border between Brazil and Argentina is an example.
Chute- It is a waterfall in which the stream passage is very narrow, forcing water through at unusually high pressure. Three Chute Falls in the Tenaya Creek falls in Yosemite National Park, California.
Fan waterfalls- These are named for their shape. Water spreads out horizontally as it descends. Virgin Falls is an example.