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To be able to identify different management strategies, distinguishing between hard and soft engineering (4-5)
To be able to give the advantages and disadvantages of different management strategies, distinguishing between hard and soft engineering (6-7)
To be able to give a detailed argument, quoting specific advantages and disadvantages of different management strategies to back up your point (8-9)
How can rivers be managed?
Literacy Target: Give written arguments for and against river management strategies
Hard & Soft Engineering Techniques
- Hard Engineering is a method of river flood
management which involves major
construction work such as building artificial
structures to control flooding.
- Soft Engineering is a method of river flood
management which works with natural river
processes.
ADVANTAGES
- Controls the discharge of the river.
- Held back water in reservoir can be used to generate hydroelectric power;
- Held back water in reservoir can be used as drinking water.
DAMS & RESERVOIRS
(hold back & release water in a controlled way)
DISADVANTAGES
- Very expensive;
- Requires large amounts of land;
- Eroded material is deposited in the reservoir and not along the river's natural course so farmland downstream can be less fertile.
ADVANTAGES
- Water is moved away quickly, protecting immediate area;
- Long-lasting.
STRAIGHTENING OF RIVER
(The river’s course is straightened by
removing meanders)
DISADVANTAGES
- Altering river channel may lead to flooding downstream, as water is carried there faster;
- Could lead to more erosion downstream because the water's flowing faster.
ADVANTAGES
- Homes close to main river safer as flood water is diverted away from them;
- Can be used for water sports.
FLOOD RELIEF CHANNELS
(Building new artificial channels which are used
when a river is close to maximum discharge)
DISADVANTAGES
- Requires large amount of land;
- Extremely expensive.
SOFT ENGINEERING
ADVANTAGES
- The impact of flooding is reduced — buildings are less damaged and people know what to do when a flood happens.
- People are also less likely to worry about the threat of floods if they're prepared.
PREPARATION
(Buildings modified and people prepared)
DISADVANTAGES
- Preparation doesn't guarantee safety from a flood.
- It could give people a false sense of security.
- It's expensive to modify homes and businesses.
ADVANTAGES
- Cheap;
- Sustainable;
- Reduces surface run-off, because less tarmac near river.
- The impact of flooding is reduced — there aren't any houses or roads to be damaged.
FLOODPLAIN ZONING
(control development close to floodplain)
DISADVANTAGES
- Local people may not be happy, particularly if there is a housing shortage;
- The expansion of an urban area is limited if there aren't any other suitable building sites.
- It's no help in areas that have already been built on.
BEFORE AFTER
ADVANTAGES
- River restoration uses the natural processes and features of a river, such as meanders and wetlands, to slow down river flow and reduce the likelihood of a major flood
- River wildlife ecosystems return.
- Little maintenance is needed as the river is left in its natural state.
RIVER RESTORATION
(Where a river’s course has been changed artificially, river
restoration can return it to its original course)
DISADVANTAGES
- Local flood risk can increase.
- people prefer the reliability of hard engineering constructions to protect their properties from flooding.
Hard & Soft Engineering Techniques
Write a leaflet to inform York Council about
different flood control techniques.
Your leaflet must include:
- Definitions of hard and soft engineering
- Examples of hard engineering – including a
description, costs and benefits
- Examples of soft engineering – including a
description, costs and benefits
