Flood Management Flashcards
Define Hard Engineering
man - made structures that are usually large scale and have a large impact on the environment
Define Soft Engineering
Involves adapting a river and sustainable solutions that work in harmony with the environment.
Examples of Hard Engineering
Dams and Reservoirs, Channel straightening, Flood relief channel and Man-made levees
Dams and Reservoirs
Dams (huge walls) are built across the river usually in the upper course. A reservoir is an artificial lake formed behind the dam.
Define dam
They are huge walls built across rivers which restricts the flow of water . It controls and usually slows down the flow of water
Define reservoirs
The artificial lake behind the dam.
Benefits of Dams
. Reservoirs stores water and release it slowly reducing the risk of flooding
. Water in the reservoir can be used for drinking and can be used to generate hydroelectric power
Disadvantages of Dams
. They are very expensive to build
. If they fails they can cause catastrophic failure
. Eroded material is deposited in the reservoir and not along the river’s natural course. This makes farmland downstream less fertile.
. Construction of Dams means heavy machinery used with can increase pollution. Habitats can also be destroyed.
Define Channel Straightening
The river’s course is straightened, widened and deepened. This means less meanders and a more efficient course which improves navigation of the river water.
Advantages of Channel straightening
Water can move out of the area more quickly as its does not travel as far as slowly due to less meanders. There is less friction with the banks and beds meaning less faster flow.
Disadvantages of channel straightening
Flooding may occur later downstream of the straightened channel instead since water is being carried there faster. It can destroy habitats.
Define Man -Made levees
They are man made embankments on both sides of the river
Advantages of man - made levees
Embankments mean that the river channel can hold more river. They are also quite cheap.
Disadvantages of man - made levees
If the levee breaks it can cause terrible flooding. Regular maintenance is also required.
Define flood - relief channel
An artificially made channel that is designed as a backup of bypass channel if a river floods.
Benefits of flood - relief channel
It provides area for boating and canoeing. Footpaths and cycle paths are made. Insurance gets lowered and new habitats can thrive in the new water.
Disadvantages of flood - relief channel
People have heave to be moved and it is very expensive for construction. It needs to repaired and maintained and habitats can be disturbed.
Issues with habitats (long term and short term)
. When building dams, relief channel and channel straightening, habitats may be destroyed in the short - term. However in the long term new species may thrive and make up for the lost of previous habitats.
Examples of soft engineering
Flood warnings, preparation, Flood plain zoning or doing nothing
Define flood warning
People gets warned about possible flooding through TV, radio , newspapers and the internet.
Advantages of flood warning
The impact of flooding gets reduce. People have time to move possessions upstairs and put sandbags
Disadvantages of flood warning
They do not stop of flood from occurring. People who are poorer may not have access to radio and television.
Define flood plain zoning
Allowing only certain land uses on the floodplain reduces the risk of flooding to houses and more important buildings. For example houses and roads are built far away from the river, whilst fields and grazing pasture lands are built closer to the river.
Advantages of flood plain zoning
Risk of flooding is reduced. Impermeable surfaces are not created such as roads. There is not many roads to damage
Disadvantages of flood plain zoning
The flood will still causes damage to certain parts. The risk of flooding is not reduced. It is not always easy to change existing land uses.
