Research on key technology for sediment management in large-scale reservoirs

The storage of the Xiaolangdi Reservoir on the Yellow River has been reducing rapidly due to sedimentation since the reservoir was commissioned. Experimental studies showed that discharging sediment with density currents at high water level was of low efficiency and the deposited sediment in the upstream part of the reservoir was difficult to discharge. Two methods of improving the de-silting capacity have been proposed. of which one is increasing the strength and transport capacity of density currents and the other is remobilising deposited sediment and pumping it out over the dam through special pipes. Both approaches require mechanical input to disturb and pump out the sediment. The authors propose a strategy to discharge fine sediment out of the reservoir by disturbing and pumping out the sediment using boats equipped with submersible pumps within an area 2-40 km in front of the dam during two periods of water-sediment regulation and power generation. This strategy can prolong the life of the reservoir and harmonise the relationship between the reservoir and the river.