levees and floodplains

Question 1

Where are levees and floodplains found?

Answer 1

In the lower course

Question 2

Why do levees and floodplains form?

Answer 2

They both involve the build-up of material during flooding

Question 3

Why are levees and floodplains unable to form in normal flow conditions?

Answer 3

The river is contained within its banks and so no sediment is available

Question 4

When are levees and floodplains formed?

Answer 4

During periods of high rainfall and discharge when the river has burst its banks

Question 5

What is the first step of forming levees and floodplains?

Answer 5

Either side of the river there is a wider, flatter valley caused by meanders shifting along the valley. The river is contained within its banks under normal flow

Question 6

What is the second step of forming levees and floodplains?

Answer 6

When the river floods, it bursts its banks. The larger material is deposited next to the channel as its speed / energy is lost. The smaller material is carried further

Question 7

What is the third step of forming levees and floodplains?

Answer 7

The levees (the deposited larger material) increase in height. Layers of the smaller deposited material is left behind the levees from many successive floods. The area behind the levees is a fertile, flat floodplain