Welcome to CoolGeography
Back to Main Back to GCSE Back to Rivers
Landforms found along river profiles - Waterfalls

3. Waterfalls by rgamesby

Landforms in upland regions are dominantly created by erosion processes, where land is worn away.  Generally, the volume and discharge of rivers in upland regions tends to be low, and the river uses much of it's energy in overcoming friction.  The erosion direction here is vertical, or straight down into the bed of the river.  This has the effect of destabilising the slopes on either side of the river, creating a steep landscape. As shown on the left, near to the Kunar River in Pakistan.

Kunar river, Pakistan

Waterfalls

Waterfalls are one  of the most spectacular landforms found in the upper valley and are created by erosion processes.
They occur where a band of hard rock (e.g. granite) overlies a softer rock (e.g. sandstone).

Erosion processes such as Hydraulic Action (the force of the water) and Abrasion (where the river rubs stones that are being transported against the bed of a river thereby breaking it down) dominate.

The softer rock is eroded quicker than the harder rock and gradually washes away downstream.

This creates a plunge pool where water is swilled around, potholing can occur here and any rocks and debris swept into the plunge pool by the river will be swirled around and rub against the bed and banks of the plunge pool (called corrasion), deepening it further.

Over time, the softer rock is eroded further creating an over hang of hard rock.  This overhang is unstable as it's weight is unsupported.

Eventually, this hard rock collapses because it is unsupported and the waterfall moves back upstream.

This creates Gorges, which are steep sided deep river valleys.  This process will repeat continually, with the location of the waterfall moving back upstream.

Niagara Falls
Niagara falls, one of the world's most famous waterfalls, but is not in the upper reaches of it's river!

Waterfall formation diagram

Above is a diagram showing the formation of a waterfall.  You can see an animation by clicking here.

Think about it
1) Find out about upper landform features from the BBC and take a test


2
) Play a rivers Penalty shoot out game from Juicy Geography!

3) Using the map below describe the shape the waterfall on the map and explain why they take that shape on the map

4) Try the quizlet set below

5) Try this gap fill exercise on waterfalls