Features formed by a river.Summary

Year 10 Geography

Features formed in the upper course of a River.

WATERFALLS

WATERFALL FORMATION In this world waterfalls are found anywhere.

Rivers or streams run through rocky landscapes.

Waterfalls are also human attractions but some times they are dangerous.

WATERFALL FORMATIONWhere are waterfalls common

found?Waterfalls are often found on rivers or

streams that run through rocky landscapes. But not just on every landscape the land it

should have a harder rock overlays a layer of softer rock.

Softer rock

Harder rock

Waterfall formationAs the river continues to passes over the

sorter rock, it is able to erode the soft rock at a faster rate because it is not strong enough to hold the volume of the water

Because of that the soft rock is slowly eaten away or eroded forming a curved ledge underneath the hard rock.

Collapsed rocks

When this happens a plunge pool can be formed at the bottom once the water had started tumbling down.

when the water starts tumbling down some of the water goes under the waterfall and under cuts the soft rock.

when more of the soft rock is eroded there isn’t enough support under the harder rock and it collapses into the plunger pool.

WATERFALL FORMATION

• The processes of erosion continues further eroding the notch and plunge pool.

• The harder rock above will collapse again meaning the waterfall will retreat upstream over time and it looks like this.

What is a gorge?A canyon or gorge is a deep

ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into.

How is a gorge formed?Most gorges are formed through water

erosion. For example, waterfalls erode the rocks they fall over and the falls move gradually back - leaving a gorge behind them. Some gorges are formed as rift valleys; land stretches and a central area drops down - this has formed the Great Rift Valley in Africa and the Great Glen in Scotland.

Three stages in gorge formation

Stage 1

Stage 2Stage 3

Features formed in the Middle course of a River.

Slip off slopeA slip off slope is formed when the

rivers’ energy is too low. The current is too slow when the river energy is low so the river cannot carry any load.

The slip off slope is formed as a result of deposition along the river bank. Material that was being transported is deposited because friction between the water and the bank is greater on the inner bank.

Slip off slope

Slip off slope

Meanders

A meander is a bend in the river, it is usually in the lower and middle course of the river where the water slides from one side of the river to the next, this erodes one side of the river bed and deposits sediment on the other to make a bend.

How it is formed.

As water in the river flows in the middle course of the river the gradient of the river is less steep so the river begins to meander.

This is because the fast flowing water on the outside of the bend erodes the side the side of the river.