The Management of Sediment in Reservoired Catchments

Abstract The rates of sedimentation in Yorkshire reservoirs are high for the UK but low compared with those reported globally. Whilst not likely to jeopardize supply, the behaviour and properties of reservoir sediments have implications for the quantity and quality of the water. Data suggest that the use of control and diversion structures reduces average sedimentation by 53m3/km2 per annum in the case of residuum lodges, and also modifies the nature of the sediment considerably, tending to allow the finer, organic particles into the reservoir. Trapping may be minimized by the diversion of high flows where such facilities exist, or by maintaining water levels at the maximum possible in supply reservoirs. Management strategies to reduce sedimentation would, in many cases, require fairly simple routine maintenance of existing structures. The short‐term cost of discarded water must be weighed against the longer‐term benefits of improved quality and reservoir capacity.