Unit 5.8 - Geo

What is a river channel?

• the place where a river normally flows

• low ground in a valley

• an area that is at risk of flood

• a place where tributaries join rivers

What is a floodplain?

• the direction that surface runoff flows in

• a fairly flat area beside a river that is likely to flood

• a temporary flood defense system

• rock below the surface that water cannot soak through

What is the main cause of floods?

• blocked river channels

• erosion of river banks

• built up areas

• heavy rain

What's the name for a sudden flood caused by a burst of very heavy rain?

• burst flood

• floodplain

• flash flood

• precipitation flood

Flood risk increases when _____ is stopped or slowed down and ______ is increased.

• surface runoff / impermeable

• impermeable / surface runoff

• surface runoff / infiltration

• infiltration / surface runoff

What is impermeable rock?

• rock which water cannot soak through

• rock which water can soak through

• rock which water soaks through very fast

• rock which holds a lot of water

How does steep land increase flood risk?

• The soil will soggy and the rain can't soak away.

• The more tributaries the river has, the greater the chance of flooding.

• Rain will run down a steep slope quickly - before it has much of a chance to soak into the soil.

• Rain can't pass through concrete.

How do tributaries increase flood risk?

• The soil will be soggy and the rain can't soak away.

• The more tributaries the river has, the greater the chance of flooding.

• Rain will run down a steep slope quickly - before is has much of a chance to soak into the soil.

• Rain can't pass through concrete.

How do built up areas increase flood risk?

• The soil will be soggy and the rain can't soak away.

• The more tributaries the river has, the greater the chance of flooding.

• Rain will run down a steep slope quickly - before is has much of a chance to soak into the soil.

• Rain can't pass through concrete.

How does heavy rain increase flood risk?

• The soil will be soggy and the rain can't soak away.

• The more tributaries the river has, the greater the chance of flooding.

• Rain will run down a steep slope quickly - before is has much of a chance to soak into the soil.

• Rain can't pass through concrete.