![]() ![]() Dredgings are frequently deposited close to the riverbank – from where they can be carried by rain straight back into the river – or on the floodplain itself. Internal Drainage Boards report the need to dredge material from channels about every five to ten years, depending on local circumstances. As a result, dredged channels require long-term maintenance. Moreover, the river will seek to re-adjust itself to a more natural form in terms of cross-sectional area, gradient and meanders, with potentially serious unintended consequences including bank failure and erosion. Rivers/canals carry runoff and silt from the catchment to estuaries, so as soon as dredging is complete, material will begin to re-accumulate. It is therefore an expensive operation.ĭredging is rarely a one-off activity. Appropriate planning is needed to take account of the numerous hazards and risks to people and the environment. The working conditions are invariably difficult, such as from a narrow riverbank. Dredging on rivers/canals often involves the deployment of large, specialist equipment. Dredging can also be used to create artificial channels that can act as sumps, from which water can be pumped. ![]() Works can be undertaken to drain land for agriculture, to improve flood protection and/or for navigational purposes. The term ‘dredging’ covers a range of activities from the removal of material from the bed and sides of river channels through to the wholesale straightening (canalisation) and/or deepening of watercourses. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |