rivers hard and soft engineering

Question 1

Name a range of hard engineering strategies used to manage river flooding?

Answer 1

Reservoirs and dams
Channel straightening
Embankments
Flood relief channels

Question 2

Name a range of soft engineering strategies used to manage river flooding?

Answer 2

Afforestation
Land use zoning
River restoration
Wetland restoration
Flood warnings

Question 3

How do dams regulate water flow?

Answer 3

Durings periods of high rainfall, water is stored in the dam.

Water is released when rainfall is low

Question 4

Why is building dams controversial?

Answer 4

They are very expensive
Land is flooded to create the reservoir
People are relocated to make way for the dam

Question 5

What are the benefits of dams?

Answer 5

They are multi purpose - so they can be used to generate HEP as well as manage river flow.
They are affective holding back water in times of potential flood
They are long lasting

Question 6

Most dam schemes are multi-purpose. What are their main functions?

Answer 6

Flood prevention
Irrigation
Water supply
Hydro-electric power generation
Recreation e.g. sailing

Question 7

What is channel straightening?

Answer 7

Cutting through meanders to create a straight channel to speed up water flow

Question 8

What are the advantages of channel straightening?

Answer 8

It moves water out of an area quickly as water passes through a straight channel quicker than a meandering channel.

Question 9

Why is channel straightening problematic?

Answer 9

It may increase the risk of flooding further downstream

Question 10

What are river embankments?

Answer 10

Raised riverbanks which allow the river channel to hold more water and prevent flooding

Question 11

What are the advantages of river embankments?

Answer 11

Embankments increase the volume of water that the river can hold, reducing the risk of flooding.

Question 12

What are the problems with embankments?

Answer 12

Not always effective. Water can rise above the embankments, causing flooding.

Question 13

What are flood relief channels?

Answer 13

A man-made river channel constructed to by-pass an urban area

Question 14

What are the benefits of flood relief channels?

Answer 14

River discharge can be controlled by using gates to control water levels.

Question 15

what are the disadvantages of flood relief channels

Answer 15

can be very expensive if constructed across high value land

regular maintenance is required to retain channel efficiency- this can be expensive

habitats may be disrupted

if concrete is used may be unnatural and unattractive

Question 16

How does floodplain zoning work?

Answer 16

It restricts different land uses to certain locations on the floodplain.
Expensive/important land uses are placed further away from the river e.g. housing and industry
Low-value uses are placed close to the river e.g. pasture and parkland.

Question 17

What are the advantages of flood plain zoning?

Answer 17

Consideration into the landuse around the river is taken which means concrete surfaces are not used, reducing impermeable surfaces close to river. Less damage occurs as important facilities are located futher away.

Question 18

What are the disadvantages of flood plain zoning?

Answer 18

It limits the uses of land closes to a river

It is almost impossible to use flood plain zoning on land that has already been built on

Question 19

What is river restoration?

Answer 19

Making the river more natural. For example:

When rivers have previously been artificially starightened they are returned to their original course.
Removing levees so that the river floods naturally
The purpose of this is to prevent flooding further downstream.

Question 20

What are the benefits of river restoration?

Answer 20

Less risk of flooding downstream
Limited maintenance needed
Creates habitats for birds

Question 21

What are the problems with river restoration?

Answer 21

Flooding can increase

Major floods are more likely unless planning takes place.

Question 22

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How does afforestation help manage river flooding?

Answer 22

Planting trees to intercept and absorb water reduces surface run off.