HU Chunhong, FANG Chunming and XU Quanxi

Abstract: The silt problem is one of the key technical problems in the Three Gorges Project. In the demonstration and preliminary design phases of the Three Gorges Project, adoption of the "storing clean water and discharging muddy flow" method was proposed for solving the silt problem. The implementation of reservoir water impoundment in 2003 showed that the reservoir generally follows "storing clean water and discharging muddy flow" scheduling principle and its mode of operation is optimized based on new conditions such as the reduction of upstream water and silt. This study systematically analyzes the advantages and disadvantages of optimization and adjustment of "storing clean water and discharging muddy flow" of operation of the Three Gorges Reservoir, including the effects of the 175m experimental impoundment implemented five years previously, dynamic changes in water level during the flood season, and effects of advanced water impoundment, on reservoir sedimentation and river channel evolution downstream of the dam. In order to providing technical support for the scientific, efficient, and safe utilization of the Three Gorges Reservoir, optimization suggestions for reservoir scheduling aim at forming a new "storing clean water and discharging muddy flow" model and maintaining long term use of the reservoir are proposed.

Key words: Three Gorges Project; silt problem; reservoir scheduling; storing clean water and discharging muddy flow; optimal scheduling