Unintended effects of dredging

Nature abhors a vacuum and removing accumulated material from a river channel can have far-reaching and unintended consequences. The first principle effect is to increase the demand for eroded river-bed and river-bank material from upstream. This can dramatically increase the rate of erosion in upstream reaches. The second major effect is the interruption of the transport of sediment downstream of the dredged reach. Whilst the bed material is being re-accumulated in the dredged area, there is far less material being supplied downstream. That "cutting off" of the sediment supply causes a net increase in the erosion downstream of the dredged reach as well. This is due to stopping the supply of material that would otherwise "patch up" and fill in eroded areas to produce a more stable dynamic equilibrium state. How many people who undertake dredging understand these processes? Is the move to "fast track" UK-landowners' ability to dredge their own streams with a much lower requirement for external assessment likely to create more problem than it solves?

Видео Unintended effects of dredging канала Wild Trout Trust