Taking the emergency disposal of large-volume floating objects in Gaobazhou reservoir of Hubei province as an example, this paper introduces the event process and risk analysis of Gaobazhou hydropower station facing the accumulation of floating objects such as large-scale fish farming cages in the reservoir due to heavy rainfall in the Qingjiang river basin. As well, the effective practice of flotsam cleanup and emergency disposal of Qingjiang Company of China Three Gorges Corporation is summarized, for reference.

From the point of view of responsibilities, interpretation of Regulation for Hydropower Dam Safety Emergency Management is performed through three aspects, namely the subject responsibility of dam safety emergency management, government- enterprise collaboration and information sharing as well as supervision and management responsibility, for reference.

All sections of the pressurized flood discharge hole along the axis are in pressure flow state, so full lining with steel is required. Due to the limitation of construction conditions, local void will happen to the baseplate of steel lining after pouring, so the contact grouting method shall be adopted to fill the void to ensure the safe operation of dam. This paper mainly introduces the construction technology and quality control points of contact grouting for the steel lining baseplate of pressurized flood discharge hole in hydropower station dam. The practice has proved that the technology is feasible, economical and reason⁃ able, and the grouting quality meets the design and specification requirements.

At present, it is difficult to record monitoring data when sluice are opened for flood discharge, especially in the case of dam deformation, the safety will be affected. Therefore, in order to understand the stability state of dam safety, a deformation monitoring system for reservoir dams based on 3D laser scanning is proposed. The working principle and equipment functions of the deformation monitoring system are introduced. The point-to-surface deformation comparison analysis mode is used to monitor dam deformation, and the source program is developed to realize the processing, comparative analysis and modeling of the integrated monitoring point cloud data. The intelligent machine system is applied to the actual monitoring of dam deformation. The results show that the system meets the design requirements in terms of stability, reliability, real-time and accuracy, resulting in higher data integrity rate.

Reasonable demonstration of impact from dam- break flood is of great significance to dam risk assessment and emergency management. When it comes to cascade dams failure, a 1D and 2D hydraulic coupling model is established to analyze the propagation of dam failure flood and the inundation of floodplain downstream the dam. Taking cascade hydropower stations on W river as an example, the impact of dam failure under two reservoir operation conditions in flood season and non-flood season, is considered in the model. The propagation of dam break flood is analyzed from aspects such as the peak discharge, maximum water level and timing of flood on typical section. On this basis, taking the maximum inundated depth of the flood plain as a representative index, dam failure flood risk level is divided and the flood risk map is drawn. The areas with high risk in case 1 and case 2 are 431.31 km ² and 575.76 km ² respectively, indicating the great impact of dam break flood on downstream areas. The simulation results have important reference value for developing emergency plans as well as disaster prevention and mitigation.