Fluvial Erosion - Waterfall

Question 1

Waterfall part 1

Answer 1

E.g Torc waterfall county Kerry

The river erosion processes involved in the formation of a waterfall are hydraulic action, abrasion and solution

Hydrolic action is the force of moving water on the land

Fast flowing water forces out loose rock and and soil,from the river bed and banks
, over time the banks collapse

Soft rocks are eroded faster than harder ones”differential erosion”

Abrasion is the wearing away of the riverbed by its load. Stones carried by the river scrape away and smooth the river channel as they move deepening and widening the river channel

Solution occurs when river water dissolves the soft rock over which it flows

These erosion processes combine to form waterfalls in the youthful stage of a drivers course

Water falls occur where a band of hard rock lies across a rivers bed

Question 2

Waterfall part 2

Answer 2

The soft rock e.g. shale is eroded more quickly

Gradually a small fall forms in the riverbed

The hydrolic force of water and abrasion combine to deepen the fall

A plunge pool forms at the base of the waterfall due to erosion caused by the weight of water and stones carried by river

Water also splashes against the back wall of the waterfall and eroded it by the process of solution

Eventually the overhanginv rock collapses and slowly the waterfall retreats upstream

This is called headward erosion

Sometimes a steep sided gorge is formed if headward erosion forms very quickly