Along with hard engineering, another technique called soft engineering can be used. This involves working with the environment to reduce the impacts of flooding but also involves working with local people to reduce the impacts of flooding. Soft engineering is generally seen as more environmentally friendly and more sustainable than hard engineering methods.
Flood plain zoning
This involves planning the land usage around a river to minimise the damage to more valuable property and land. Restrictions on what a flood plain can be used for are put in place, so only low value land usage such as public recreation areas and grazing land are located in the areas most likely to flood. this allows the river to naturally flood, whilst reducing the cost of damage when flooding occurs.
However, one problem with this is that it limits development in certain areas, which could bring an economic disadvantage to the area as the land may have been used for new businesses or for affordable residential housing. also, a lot of areas already have development on a floodplain so the situation of flooding cannot be prevented without removing all development from a floodplain, which would be unrealistic due to the economic damage I and social conflict it would cause.
Afforestation in when trees are planted in a river’s drainage basin to reduce the surface run off, that increases a river’s discharge, by acting as interception. Rainfall is caught in the leaves and absorbed through the roots leading to less water entering a river, reducing the chances of a river flooding.
Afforestation can be very effective due to the way it intercepts rainwater, especially when it is combined with flood plain zoning. It also creates new habitats for animals and leisure areas for the public, which could lead to tourism that could economically benefit local towns. Trees act as natural water filters too, which will make rainwater safer to drink and use.
However, afforestation can be expensive as large areas of land will need to be brought and planted up to make the scheme worthwhile. These trees will need maintenance too; adding to the cost. Also, unless the trees are evergreens, they will lose their leaves in the winter months and will not be as effective at intercepting rainfall when, typically, the rainfall is at its highest amount during the year.
During periods of heavy or prolonged rainfall, flood warnings are sent out to the public, particularly those who live in a flood prone area. these warnings are usually sent out through the media by the met off ice and the environment agency. these warnings enable people to move vulnerable items in their homes to higher areas, protect their homes as best they can and evacuate in time if necessary. the environment agency has a three-tier warning system ranging from a flood alert to a flood warning then a severe flood warning; the latter indicating a possible danger to life.
This method of flood prevention allows people to reduce damage caused by flooding, both in property and lives.
However, some predictions can be wrong by either warning of flooding when no flooding actually occurs, which causes unnecessary panic, or warning of the wrong intensity such as a warning of a flood alert when a severe flood warning is more appropriate will still leave people unprepared for the real severity of flooding.
- information on soft engineering techniques sourced from: http://geographyas.info/rivers/flood-management/
- information on the environment agency flood warning system sourced from: http://www.environment-agency.gov.uk/homeandleisure/floods/31618.aspx
- River management: the pros and cons of hard engineering (vamoswearegolden.wordpress.com)
- what makes some rivers more susceptible to flooding than others? (vamoswearegolden.wordpress.com)