Flooding

Question 1

Define a flood

Answer 1

A flood is temporary excess of water that covers areas which are usually dry.

Question 2

River Derwent Case Study - Causes of flooding

Answer 2

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Question 3

Give three positive impacts of floods on people.

Answer 3

1. Replenishes drinking water supplies, especially in wells
2. Provides sediment that naturally fertilises the soil of the floodplain
3. Countries such as Bangladesh or Egypt rely on floods due to the droughts they face.

Question 4

Give three negative impacts of floods on people.

Answer 4

1. Floods spread waterborne diseases
2. People and animals can become homeless or drown
3. Buildings and infrastructure can be damaged or destroyed.

Question 5

Give two positive impacts of floods on the environment.

Answer 5

1. Fish benefit because they can breed in the stagnant flood water.
2. In dry areas, floods can relieve drought by providing drinking water for wild animals.

Question 6

Give two negative impacts of floods on the environment.

Answer 6

1. Flooding can wash chemicals and sewage into local rivers, thus polluting them
2. Wild animals can lose their habitat or drown in a flood.

Question 7

Give three ‘hard engineering’ river management strategies.

Answer 7

1. Building a dam or reservoir in the upper course of a river
2. Deepening and widening the river channel
3. Building high embankments along the side of a river to contain the discharge.

Question 8

Why is deepening and widening the river or building high embankments along the side of the river an effective strategy to reduce the risk of a flood?

Answer 8

This allows the river to contain more water and therefore, there is a greater discharge required for a flood (positive aspect of deepening/widening).

Question 9

State the positive aspect of building a dam or reservoir in the upper course of a river.

Answer 9

The reservoir can be used for leisure or hydroelectricity.

Question 10

State the negative aspect of building a dam or reservoir in the upper course of a river.

Answer 10

The reservoir may flood farmland, displace local people and destroy habitats.

Question 11

Give three soft engineering river management strategies.

Answer 11

1. Afforestation in the upper course of the river
2. Land use zoning, where areas most likely to be flooded are not urbanised
3. Washlands

Question 12

Explain what is meant by ‘Washlands’

Answer 12

Washlands are part of the river’s floodplain in the lower course, where a river can flood into temporarily.
They act as a flood storage area.

Question 13

Case study: Mississippi River, South East USA - Evaluation of river management strategies

Answer 13

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