Geology can increase the risk of flooding when:

• The upland bedrock is impermeable, such as slate, which means there is more surface run-off
• Soil in low lying areas is made up of clay. Because it is so compact it is difficult for infiltration to occur.
• Areas of permeable rock, such as limestone, become inundated with water leading to increased surface run-off

Find out more about human and physical causes of flooding.

Large boulders and rocks are rolled along the river bed.

Find out more about how rivers transport material.

Discharge increases downstream because of additional water from tributaries. Velocity increases due to the additional water from tributaries and less water is in contact with the bed and banks so there is less friction.

Find out more about the long profile of a river.

Soft engineering involves working with nature and adapting to a river and learning to live with it.

Find out more about soft engineering.

Small pebbles and stones are bounced along the river bed.

Find out more about how rivers transport material.