Rivers- formations Flashcards
Waterfall
As water flows over a band of hard rock and then onto a layer of softer rock, it begins to erode, here a plunge pool is formed though the processes of hydraulic action and corrasion. As the water continues to flow it undercuts the harder rock and it eventually collapses. This process repeats and the waterfall moves upstream.
V-shaped valley
As soon as a river starts to flow down a hill it has lots of energy and so begins to erode the rock by corrasion and hydraulic action. As a small valley begins to form,physical weathering of the land beside the river produces loose rocks which fall into the river to help with erosion of lay at the side to form a v-shaped valley.
Meanders
In a river there are abnormallities in the river bed that cause the water to flow faster or slower, where the river is flowing faster it erodes through the process of hydraulic action and corassion, where it is slower it deposits, over time this begins to form a bend in the river called a meander.
Oxbow lakes
When a river is meandering the processes of hydraulic action and corasion continue to make the bend steeper, eventually the bends will erode through to form a straight channel, the river will then deposit to block off the old bend and here an oxbow lake is formed.
Levees
When a river overflows its banks it has lots of energy that it losses very quickly, this causes it to drop its load very quickly, the largest particles and dropped first and build up beside the river bed to form a natural levee
