How Can A Waterfall Be Formed?

Waterfalls are formed by erosional processes- Hydraulic, corrasion and attrition action. Waterfalls form where rivers meet a less resistant rock, after flowing over more resistant rock. The hard rock eventually collapses into the plunge pool at the bottom and the soft rock is eroded back.

Waterfalls are formed due to the erosive activity of the watercourse, flowing over varied layers of rocks that have different rates of erosion. Let's discuss about two consequences of erosion; a watercourse traversing over a soft rock layer will have higher rate of erosion, in comparison to another area with a hard rock layer. Over a period of time, the erosion process further continues to erode the soft rocks, resulting in the steepening of the watercourse beyond the layer of hard rocks.

In such a condition, the soil erosion rate is also accelerated due to steepening effect and increased speed of the watercourse. Eventually, the steepness of the watercourse increases and a stage comes in which the slope becomes almost vertical and/or totally vertical, leading to the formation of waterfalls. The base where the waterfall lands, is called a plunge pool.

A river flows above a layer of soft and hard rock. The hard rock is actually above the soft rock. As the river flows, it erodes away the soft rock, slowly. Continual erosion causes part of the soft rock to erode away. As there is no support for the hard rock from the soft rock, the hard rock hangs and eventually collapses. The river then plunges from a great height which is called  a waterfall. However, the full formation of the river is not completed yet. Due to the great impact of the river plunging from a great height, a plunge pool is formed at the base of the waterfall. People are not encouraged to swim there though it is refreshing as the currents in that area is very strong that even the greatest swimmer cannot escape and will drown.
                                                                                          - Divya Subramaniam 1E4 2009
                                                                                            St. Margaret's Secondary School

Well it erodes the softy rock this is called erosion as the soft rock has eroded the hard rock will collapse into the plunge pool then this process will repeat it self

A waterfall is a natural formation which is formed when a water body such as a river breaks the rocks underneath it and causes them to erode. The erosion will then break the elevation of the river causing the river to fall from a height. The elevation keeps breaking as the years go by which makes the waterfall. Ultimately, the soft rock collapses and only the hard rock remains causing the water to fall from a height. There are many different types of waterfalls and all depends upon the flow of the current and the type of the river. Some of the types of waterfalls are block, cascade, tiered, horsetail, plunge and many more.

Waterfalls are usually found in mountain regions or places where the elevation is quite high such as hills, plains etc. Angel Falls in Venezuela is the world's highest waterfall at more than 3000 feet.