Schemes set up to work with the natural processes along the river to reduce the effects of flooding.
Flood warnings and preparation
Developing a system of alerting people to the risk of flooding. In the UK the Environment Agency is responsible for warning people about flooding through the TV, Radio, Internet, newspapers and apps.
The impact of flooding is reduced as people are better prepared. There is more time for people to move things upstairs, put sandbags and other flood defences in place and evacuate.
Warnings do not stop a flood event. Not all people will be aware of flood warnings.
This involves putting building restrictions in place on floodplains that are at risk of flooding.
Buildings are not constructed in areas at risk of flooding. Impermeable surfaces are not constructed on the floodplain which means the risk of flooding is not increased.
The growth of urban areas can be limited if building on floodplains is restricted. The risk of flooding is not reduced in areas of floodplains that are at risk of flooding but have been built on in the past.
Planting trees increase interception and lag time (the time between the peak rainfall and peak river discharge). This reduces the risk of flooding.
Discharge in the river is reduced. The trees also reduce the risk of soil erosion, which can reduce the capacity of the river channel to carry water.
Restricts what land can be used for, particularly in the upper stages of the river valley.
River restoration involves returning a river to its natural state. This can involve removing man-made levees or removing river straightening.
Discharge in the river reduces meaning there is less risk of flooding downstream. Little or no maintenance is required which makes this a low-cost solution. Biodiversity is maintained along the river.
Flood risks can increase if nothing is done along the river.