In the past this has sometimes come with unintended consequences including increasing flooding downstream.ĭredging and desilting are not as effective at reducing flood risk as other options, are often expensive and can be harmful to the environment. In the UK, dredging and desilting have historically been carried out for a broad range of reasons: to drain land, maintain flows to mills, abstract sand or gravel for construction or to improve navigation, in addition to preventing flooding. It is undertaken less frequently and is a bigger exercise. We use dredging to describe removing a range of materials or for making the channel larger by removing the bed and channel side material. Dredging and desilting are methods that we use to remove an accumulation of silt material, such as fine gravels or soils that have been washed into rivers from surrounding land in the catchment, from the bottom of rivers to temporarily increase the flow.ĭesilting is usually undertaken more frequently to remove recent deposits of silt to the bed level of a river.

Dredging definition