Molluscs and amphibians which are important parts of the aquatic ecology can also suffer death from dredging equipment.ĭredging has significant impacts on fish and amphibians during reproduction. If they do survive, they will experience higher mortality rates due to injuries, physiological stressors, disorientation, abrasions and infections. Furthermore, deeper habitats may make a river more vulnerable to exploitation by invasive non-native species.įish eggs, fry, larvae and juveniles can be sucked up and displaced by dredging, which will cause death. The loss of natural habitat can render new dredged habitats unsuitable for shallow-water fish.
Many fish species depend on structured habitats for refuge from the current. River dredging can have a number of impacts on local fish populations. Besides, loss of soils will disturb the habitat of river bank fauna. This will increase light penetration and hence water temperature, which will cause fish to migrate. Moreover, disturbance of bank vegetation caused by erosion will remove cover and shade. Eroded banks will stimulate further build-up of silt, exacerbating rather than improving problems with navigation. After a river is dredged, its banks will become prone to erosion.
During the dredging process effects may arise due to the excavation of sediments at the bed, loss of material during transport to the surface, overflow from the dredger while loading and loss of material from the dredger and/or pipelines during transport.ĭredging will affect a river's composition, diversity and resiliency in a variety of ways. The impacts are generally two-fold – firstly as a result of the dredging process itself and secondly as a result of the disposal of the dredged material.
The impacts of river dredging on the aquatic ecosystem and the life it supports have been relatively well-studied.
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