Hard and soft engineering. Flashcards
Dams.
Description:
Allow water to be stored temporarily in a reservoir and regulate the rate at which water passes down a river.
Advantages:
Allows irrigation of land below the dam throughout the year.
Can be used for recreational activity.
Disadvantages:
Expensive.
Land is flooded when the reservoir is created.
Farmland is flooded.
People may be displaced by the flooding.
Wildlife my be affected e.g. fish migrating upstream.
Can increase erosion upstream.
Embankments.
Description:
Artificially raised and strengthened banks that enable a river to carry more water.
Advantages:
Can be used as path for pedestrians.
Concrete embankments are effective at stopping bank erosion.
Can provide a habitat for animals.
Disadvantages:
Banks are not built high enough.
Concrete embankments can be an eyesore in rural areas.
Channelisation.
Description:
River channels have been artificially lined and straightened with concrete.
Advantages:
Effectively protects the immediate area as water is moved quickly away.
Long lasting.
Disadvantages:
May lead to greater risk of flooding downstream as water is carried away faster.
Unnatural.
Flood relief channels.
Description:
These are built where it is difficult or too expensive to modify the existing channel.
They take excess water around the settlement.
Advantages:
Makes people who live close to the stream safer as the flood water is diverted into the relief channel.
Can be used for water sports.
Disadvantages:
They require a large amount of land which may be difficult to purchase if it is productive land.
Expensive.
Flood storage reservoirs and balancing lakes.
Description: Excess water can be stores in reservoirs and used for other purposes such as recreation. Advantages: Natural looking. Does not damage the environment. Disadvantages: Need a large area of land. Expensive. Only come into use when the river has flooded.
Floodplain zoning.
Description:
Local authorities and the national government introduce policies to control urban development close to or on the floodplain.
Advantages:
A very cheap and effective way of reducing the risk of damage.
Sustainable (reduces the impact of flooding and building damage is limited).
Surface runoff is less likely to happen.
Disadvantages:
Can be resistance to the restricting of housing if there are housing shortages in an area.
Enforcing planning regulations and controls may be harder.
Warning systems.
Description:
A network of sirens which give people early warning of possible flooding.
Environment Agency uses TV, radio, email, fax and text.
Advantages:
Cheap system.
Effective way of communicating with people.
People are warned so they can move their belongings to a safer place.
Disadvantages:
Not all people will look at mobile phones.
Afforestation.
Description:
Planting trees to increase the amount of infiltration and interception to avoid the amount of surface run off.
Advantages:
Cheap and natural.
Disadvantages:
Conifers are planted which can make the soil acidic.
Dense plantations spoil the natural look of the landscape.
It increases the fire risk because of leisure activities.
