Integrating mechanical and hydraulic methods to improve desilting efficiency

This study uses field observations and physical model tests to develop and validate a two-dimensional numerical model to simulate turbidity currents, sediment transport, and sediment outflow trends. In addition, the study provides and emphasizes the crucial role of a dredged guiding channel in increasing turbidity concentration near the dam of Nanhua Reservoir, thereby enhancing desilting efficiency. This channel significantly improved sediment removal during sluicing operations, effectively capturing turbid water transport dynamics and sediment load patterns. Simulation results showed minimal differences in sediment transport time across operational scenarios, with sluicing operations achieving the highest desilting efficiency while free overflow conditions had the least impact. Notably, the desilting tunnel outperformed the spillway for similar outflow volumes, achieving the highest sediment concentration ratios during sluicing. Sediment transport analysis revealed a decline in concentrations as sediment moved through the reservoir, with a strong correlation between upstream inflows and critical measurement points within the system. These findings highlight the importance of integrating dredged guiding channels and optimizing desilting tunnel operations to enhance sediment control, particularly during high inflow events and elevated reservoir levels—especially for midstream desilting tunnels. This research offers new hydraulic insights for effective reservoir sediment management, contributing to sustainable water resource management in sediment-affected regions.