Attrition is when sediment particles knock against the bed or each other and break, becoming more rounded and smaller as you move down the river.

Find out more about river erosion.

The characteristics of rapids include:

• the turbulent flow of water
• white water
• uneven river bed
• steep gradients.

Find out more about the landforms of erosion in the upper course of a river.

Rapids form when there is vertical bedding which is when alternate bands of hard and soft rock cross the channel. Differential erosion will occur as the soft rock is more easily eroded than hard rock. This makes the riverbed uneven and river’s flow becomes turbulent leading to white water sections typical of rapids.

Find out more about the landforms of erosion in the upper course of a river.

Economic benefits of constructing dams and reservoirs include:

• boosting tourism e.g. the local economy of Kielder has been boosted by £6 million thanks to the construction of Kielder Dam
• they can be used to produce electricity by passing the water through a turbine within the dam

Find out more about hard engineering.

Rapids are fast flowing, turbulent sections of the river where the bed has a relatively steep gradient. They are found in the upper course of the river.

Find out more about the landforms of erosion in the upper course of a river.