Explain the formation of one landform of erosion formed im a fluvial environment

Question 1

Intro

Answer 1

In this answer I will be discussing a waterfall, a fluvial landform of erosion

Rivers are significant agents of shaping the Irish landscape through erosion, transportation and deposition

A waterfall is a vertical drop in the bed of a river

Formed through vertical erosion in the upper course of a river through hydraulic action, abrasion, attrition and solution

Question 2

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Answer 2

A waterfall develops when a band of hard rock lies across a riverbed which also contains softer rock

Usually limestone or ORS in Ireland

It prevents the river from achieving a smooth river profile

Hydraulic action is the force of moving water as it flows across the riverbed
It erodes soft rock more quickly than the harder rock (differential erosion)

A small notch and fall develop at location of the soft rock In the bed of the channel

Over time and with continued erosion rapids develop and the fall is deepened by abrasion e.g Torc Waterfall

Question 3

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Answer 3

Abrasion is the wearing away riverbed using the rivers load of rocks and pebbles

As a result of combined action of hydraulic action and abrasion, a plunge pool is formed from the notch at the end of the developing fall

Plunge pool is deepened by the swirling action of the water, also known as eddying

Water splashing against the back wall of the fall may contribute towards dissolving rock through solution

Undercutting at the base of the fall occurs through HA and creates an overhang, eventually the overhang will collapse and a vertical drop is formed, now called a waterfall

Over time the waterfall retreats upstream as headward erosion and also erodes harder rock

Often a steep-sided gorge is formed from headward erosion over a long period of time e.g River Barrow