Abstract: The scheduling for sediment discharge from the Three Gorges Reservoir (TGR) is a crucial technical issue influencing its safe operation and overall benefits. Based on long time series measured water and sediment data and reservoir operations, we expound the water and sediment characteristics in TGR during flood season, the sediment peak forecasting techniques and sediment reduction scheduling strategies in practice. Results indicate that after 2012, the flood season runoff in TGR constituted 45% of the annual total runoff, while sediment transport during this period reaching 84%. The proportion of sediment transport during each flood event notably increased, highlighting an asynchronous pattern between water and sediment transport. Leveraging real-time monitoring data, we built a sediment forecasting system integrating multi-form boundary prediction model and reservoir water-sediment transport model. This system forecasts the time of sediment peak arriving dam and the corresponding sediment load, offering technical support for sediment reduction dispatch during flood season. Successful operational tests of sediment peak discharge in TGR have yielded expected outcomes, significantly increasing sediment discharge ratios within the reservoir. During each flood event, sediment discharge ratios ranged from approximately 27% to 39%.

Key words: Three Gorges Reservoir, sediment deposition, water and sediment characteristics, sediment forecast, sediment reduction dispatch