Managing flooding
River management
Steps can be taken to manage flooding. This is known as A technique/method that is used to reduce the likelihood of flooding and damage due to flooding.. Often these steps involve trying to lengthen the amount of time it takes for water to reach the river channel, thereby increasing the lag time.
When a river is managed in such a way so that it needs major building work to stop the river from flooding. Usually machinery and concrete/ building materials are used. tend to be more expensive and have a greater impact on the river and the surrounding landscape. They will require more extensive alterations to the river to try to stop flooding.
When a river is managed in such a way so that it needs limited building work and floods are more prevented than managed. These measures are usually more sustainable than hard engineering methods. are usually more ecologically sensitive. They will attempt to manage flood rather than prevent it.
Hard-engineering
Dams
- Built along the course of a river to control the amount of discharge. Water is held back by the dam and released in a controlled way.
- Water is usually stored in a A man-made pool of water used to store drinking water. behind the A high wall that is built across the river channel to stop the river from flooding. Dams are built from concrete and the risk of flooding is nearly completely reduced (hard engineering). . This water can then be used to generate Electricity generated from water. power or for recreation purposes.
- Expensive to build.
- A settlement is a place where people live and work. They come in all shapes and sizes 鈥 they can be as large as megacities like London or as small as individual houses dispersed across the Lake District. and agricultural land may be lost when the river valley is flooded to form a A man-made pool of water used to store drinking water..
Flood walls
- Can be used to raise the height of the river bank to a level where the river might not burst its banks.
- Can be permanent features or incorporated into the design of an area and become invisible.
- Can also be temporary structures where flood gates or removable Hydraulic engineering control elements used in floodgates to adjust the water level or discharge in a river, canal, or reservoir. are built to protect a stretch of river.
Levees and embankments
- Artificial A buildup of alluvium on the banks of a river which will raise the river bank due to the repeated flooding of the river. The biggest, coarsest material will be dumped close to the river bank. can be built along river banks so that if the river floods, the water will not be able to breach the wall and cause damage. Levees can be expensive and can spoil the look of rivers.
- Flood This is a large area of material that is built up alongside rivers in rural areas to protect the river from flooding (hard engineering). are usually used in rural areas. They can take up a lot of space and are cheaper than A wall built along a river bank to stop the river from flooding. This can be incorporated into the design of an area or can be temporary (hard engineering). but they can also cause the speed of the water in the river to be increased which will just move any potential flooding further downstream.
River engineering
- The river channel may be widened or The river channel can be widened or deepened to help it carry the water downstream more efficiently (hard engineering). allowing it to carry more water. A river channel may be straightened so that water can travel faster along the course. The channel course of the river can also be altered, diverting floodwaters away from settlements.
- Altering the river channel may lead to a greater risk of flooding downstream, as the water is carried there faster.