There are two types of management techniques - soft management and hard management.
Hard management: Man-made structures to prevent or control flooding
Soft management: Working with natural processes to manage flood risk
Hard management: Man-made structures to prevent or control flooding
Soft management: Working with natural processes to manage flood risk
Management technique |
Hard or Soft? |
How does it work? |
Advantages |
Disadvantages |
Dams |
Hard |
Building a wall across a river in order to control the amount of water in the main river channel at any one time |
It is a multipurpose strategy. It reliably prevents flooding downstream, can be used for irrigation and also can be adapted to produce hydro-electric power. |
They cost huge amounts of money. The reservoir behind the dam usually floods a large amount of land so people might have to be moved from their homes. |
Channel Straightening |
Hard |
Cutting through a meander to create a straight channel to speed up the flow of water. |
If the river flow is sped up, then the excess water in a flooding scenario is moved away from the area at risk. |
It increases the risk of flooding further downstream. The issue of flooding isn't solved - it's just moved elsewhere. Concrete channels can be unattractive and can damage wildlife habitats. |
Embankments |
Hard |
It is a raised river bank that can be made out of concrete or soil. It allows the river channel to hold more water before flooding occurs. |
Concrete embankments can be a type of effective flood management. Soil embankments can be created from the river bed which deepens the channel further, is sustainable and looks more natural. |
Concrete produces CO2 and damages the most fertile top layer of soil. |
Flood relief channels |
Hard |
A man- made river channel constructed to by-pass an urban area. it is another way to enable a river to hold more water before it floods |
It can create new environments such as wetlands. It can also encourage tourism by creating an environment for activities such as walking and fishing. |
The process of creating a new river has to cut through land that is already is being used e.g. farmland. |
Floodplain zoning |
Soft |
It restricts different land uses to certain locations on the floodplain. Areas of high value land use is kept away from the river and low value land use is kept in flood risk areas. |
It reduces the cost of flooding significantly. |
It doesn't actually prevent the flood, it just reduces the cost. The owners of the low value land uses will see no benefit. It can cause land values to fall and can be hard to achieve if the land ahs already bee developed. |
River restorations and wetlands |
Soft |
If a river has been artificially changed, this restores it to its natural form. it can involve putting meanders back into rivers or restoring wetlands. |
Afforestation as part of the restoration can reduce food risk through increased interception. Meanders and wetlands slow down the river flow and reduce the likelihood of flooding downstream. Wetlands can be really good natural stores of water in a flood scenario. |
Where the river flow is slowed down, this will increase flood risk in that specific area. |
Flood warning and preparation |
Soft |
Rivers are monitored by satellites and computer modelling. The Environment Agency issues flood warnings and risk maps. |
Local authorities can use the maps to plan responses to floods. e.g. temporary flood barriers, evacuating people, closing roads and securing buildings. |
Flood protection is based on probability and can influence factors such as land values in an area. The effectiveness of flood warnings rely on people following their recommendations and that doesn't always happen. |
Afforestation |
Soft |
Planting trees to increase interception. |
It is a natural way to use natural processes to prolong the time between precipitation and the water making it to the river (lag time). |
There is only so much water that can be intercepted so this strategy alone won't be able to cope with heavy amounts of rainfall or rainfall over a prolonged period of time. |