Afforestation Scheme
This involves planting trees upstream within the drainage basin of a river.
It would need a very large area to plant the trees.
Takes time for the trees to grow.
Reduces the amount of water getting into the river, as the trees intercept water by their
leaves or soaking it up in their roots.
Reduces the amount of soil washed away that could reduce the depth of the river.
Dam
A large permanent structure that is constructed across the river with a reservoir
forming behind it.
If they are built on tributary rivers they can control water flow and stop flooding.
Large areas are flooded losing farmland and housing.
Very expensive.
Flood Barrier
A large structure that is controlled mechanically so that a barrier can be placed across
a river during times of flood. (Normally over tributaries of the main river)
Water Meadow
An area of land either side of the river that is left undeveloped, when the river floods
this area will be covered by water. (Usually farmland)
When a river is in flood it will drop sediments making the land very fertile.
A natural method of flood prevention, it allows the river to flood onto the land that
will soak it up.
Large areas of land need to be left undeveloped
Sandbags
Used to produce a temporary barrier against the water. Usually around housing as a
last minute protection.
Allows temporary barriers to be built, therefore reducing the damage to property.
A very quick and easy method of flood defence.
Does not stop the flood occurring only reduces the impacts
Water levels may rise above the sandbags.
Embankments
Along the sides of the river mounds, usually of earth are placed to protect the land
behind.
Increases the height of the river, therefore reducing the chance of flooding.
Uses natural materials usually and so there is no damage to the environment.
Needs to be constantly renewed, as they will get eroded in a flood. (Especially if they
are made from earth.)
River Straightening
A new channel is made for the river taking out meanders so that the flow of the river
is faster.
Speeds up the flow of the water going from source to mouth, therefore keeping water
levels down
Needs to be constantly checked, as the river naturally wants to meander.
Channel Dredging
Diggers are used to take sediment and material from the bed of the river, this
increases the depth.
Increases the depth and width of the river so it can contain more water.
Sediment that is dredged can be spread on the land to increase the fertility.
Will have to be done every few years, as the sediment will build up.
Evacuation Scheme
With reliable weather forecasts, flooding can be predicted and people will be able to
leave their homes before it happens.
Gives people plenty of warning to be able to leave the danger areas.
Gives people time to prepare and reduce damage to property.
Does not stop the flood from occurring and so the damage is still done.