River management

Question 1

What are some hard river defences?

Answer 1

Dams
Flood relief channels
Flood walls
Enbankments

Question 2

What are some soft river defences?

Answer 2

Floodplain zoning
Warning systems
Afforestation
Washland

Question 3

What is a dam, and what are its advantages/disadvantages?

Answer 3

• used to control discharge as the dam holds back water, then releases it controllably

ADV:
-water in reservoir can be used for hydroelectric power
DIS:
-settlements and farms destroyed for reservoir
- sediment is trapped behind the dam wall leading to further erosion downstream

Question 4

What is a flood relief channel?

Answer 4

• where the channel course of a river is altered to divert floods from settlements
• people living closer to the river can be safer
• can be expensive

Question 5

What is a flood wall?

Answer 5

• a vertical barrier made of prefabricated concrete
• good for areas with limited space
• has to be assembled well so water doesn’t get in joints

Question 6

What are enbankments?

Answer 6

• raised banks along a river
• can be used as a path for pedestrians
• can be ugly and spoil scenery

Question 7

What is floodplain zoning?

Answer 7

• where local authorities introduce policies to avoid building on floodplains
• cheap and sustainable
• can be difficult in LIC’s and places short of housing

Question 8

What is a warning system?

Answer 8

• sirens used to warn people of floods through electronics like mobile and TV
• cheap and is effective
• may not be enough time for people to prepare

Question 9

What is aforrestation?

Answer 9

• where trees are planted in catchment areas to slow down flow of water into river
• cheap
• can spoil natural scenery

Question 10

What is washland?

Answer 10

• where rivers naturally flood a waste land to prevent flooding elsewhere like a settlement
• cost effective and may produce farmland
• leaves large areas of land unbuildable