Evaluating the Effectiveness of Regulation Schemes in Improving Navigation Condition of Reservoir Channels

Abstract

Sedimentation has become a world-wide issue for almost all types of dam reservoirs. The impact of sedimentation on navigation is mainly reflected in the obstruction of navigation channels, usually at reservoir ends. The issue can be partially solved by joint water-sediment regulation during the drawdown period, called “sedimentation-reduction (SR) regulation”. It aims to enhance scour at shoals by increasing the outflow of the reservoir and accelerates the water level decline. In general, the more inflow discharge or lower dam water level, the better scouring effects, although the waste of water for hydropower generation also needs to be considered. In this work, we propose a model to evaluate the effectiveness of SR regulation schemes in improving navigation condition of reservoirs channels. The constraints for successful regulation operation are analysed in details. The navigation benefits are estimated by the increment of sediment transport volume, and the power generation impacts are estimated by the loss of effective water head. The model gives optimal starting dam water level and corresponding inflow discharge. The results were compared with actual regulation parameters of the Three Gorge reservoir. This work can provide guidelines for reservoir sediment management.