Water conservancy and hydropower projects have the characteristics of long construction period, complex structure, and being greatly affected by natural factors. An accidental factor in operation may sometimes lead to systematic safety accidents of the whole hydropower station. The author summarizes some typical cases of domestic hydropower station accidents in recent years, and analyzes some risk factors needing attention in the construction and operation management of hydropower stations, to provide reference for design, construction and operation management.

According to SL 274—2020 Design Code for Rolled Earth-rock Fill Dams, Sherard inverted layer design criteria are recommended. Based on the characteristic particle size of protected soil, the characteristic particle size of filter material and the envelope are calculated, and constraint condition for the closure and recovery of the crack in impervious body is presented, which make the inverted layer more reliable and reasonable.

Data abstraction and structure design are the foundation of application system construction, which are related to the practicability, scalability and stability of the system. Before the application system is put into service, the necessary work flow is to initialize the system, create an instance of the management objects for the system, and then applications are implemented. This paper, taking dam safety monitoring and management information system - iDam as an example, elaborates its basic data structure design and implementation of initialization, for reference.

This paper describes the relationship between the dam safety video surveillance system and other systems, and summarizes the objects and contents to be monitored. Also, selection of right frontend device, communication, control, storage and display equipment based on the characteristics of hydropower dam and monitoring objects is introduced. In accordance with the principles of practicability, reliability, economy, advancement, maintainability expandability and upgradability, the dam safety video surveillance system is designed to meet the needs of dam safety management.

HK-968 elastic epoxy coating is modified by chemical toughening. It combines the elasticity of polyurethane materials with the strength and adhesion of epoxy materials. It cures at room temperature and has better durability on the concrete surface which exerts good effect on the treatment of difficult problems such as cavitation and abrasion damage of hydraulic structures. This paper introduces the development process of HK-968 elastic epoxy coating from the aspects including main agent selection,
performance tests and adjustments, durability tests and so on, and two application cases are presented, for reference.

Earthquakes, especially strong earthquakes, may easily cause dam accidents. The actual damage of the dam is determined by the earthquake intensity, which is related to the earthquake magnitude, hypocenter depth, geological structure and the distance between the dam and the hypocenter. To realize the graded warning for dams under the condition of earthquake, it is necessary to use the statistical model to quickly calculate the earthquake magnitude at the dam site and compare it with the design standard. By computer programming, the above-mentioned functions can be realized, which can quickly locate the dam that may be damaged by the earthquake and realize rapid early warning for the dam.

The“1·12”water inrush accident of Guanzhou hydropower station reflects the problems that the main responsibility of safety management is not implemented, the procedures of bidding and procurement are chaotic, and the quality of pipe bulkhead is poor. Enterprises in charge of the operation and management of hydropower stations should learn from this accident. In order to eliminate risk factors and ensure the operation safety of power stations, responsibilities of relevant departments should be fulfilled, technical management should be strengthened, and the sensitivity and responsibility of operation management personnel should be improved.

This paper collected and reorganized the calculation results of dam-breach flow of some hydropower stations in the power industry, and summarized and analyzed the current status of dam-breach flow calculation from the aspects of calculation methods and breach shape. The results showed that there were some problems in dam-breach flood analysis, such as improper selection of calculation methods and random assumption of dam breach shape. The suggestions provided in this paper could be used as a reference for dam breach analysis and research in similar projects.

GB/T 51416—2020 Technical Standard for Concrete Dam Safety Monitoring specifically points out that concrete dam safety monitoring should run through the whole life cycle of concrete dam design, construction and operation. In each stage of the period, the objectives in stages should be accomplished, equal importance should be attached to the operation, maintenance and construction of the monitoring system, and equal attention should be paid to patrol inspection and instrument observation, data
analysis and acquisition as well as risk early warning and feedback analysis. To accurately understand this new concept, combined with the current status of concrete dam safety monitoring, the relevant contents are briefly introduced and explained, for reference.

With the development of information technology, the traditional paper-based hydraulic patrol inspection work is gradually transformed into a patrol inspection management system (module). At present, the patrol inspection system still has some problems. For example, the patrol inspection objects are not abstractly classified, the defects are not objectified, and the functions of patrol inspection App are simple. Aiming at the above-mentioned problems, the optimization design scheme is proposed and applied to the patrol inspection module in the dam safety information management system for Yalong river basin. Web terminal and mobile terminal (App) are mainly included in this module and functions such as viewing tasks, patrol inspection, result recording and query, defect tracking and query are available. With the help of information management means, this system can optimize the information management mode of hydraulic patrol inspection and further improve the level of dam safety information management.

Patrol inspection is an important means to ensure the safety of hydropower stations. Based on summary of the advantages and disadvantages of traditional patrol inspection schemes, combined with digital inspection methods, this paper proposes an optimized scheme and a new online inspection system scheme is formed. Upgrading of inspection functions, the optimization of inspection types and content as well as the optimization of inspection systems are realized. After the scheme optimization, the degree of data structuring has been improved, the data redundancy has been significantly reduced, and the defect management function has been added. Moreover, the online inspection system designed based on this scheme has been applied to Ertan hydropower station.

Aiming at the problems such as low work efficiency, weak professional level, and poor timeliness existing in the manual analysis, information technology is adopted and a set of dam safety monitoring data diagnosis and analysis system is designed and developed, which has obvious advantages in monitoring data preprocessing, distribution map drawing, engineering analogy, abnormous situation feedback, and et al. As well, it can realize the automatic generation of monthly reports, quarterly reports, annual reports, earthquake express reports and comprehensive monitoring data analysis reports. The application shows that the system can significantly improve the efficiency and quality of dam safety monitoring data diagnosis and analysis work, and it is worthy of promotion in dam safety management industry.

Intelligent pattern classification of dam safety monitoring data is researched. Combining with the characteristics of engineers' thinking and deep learning, the technical scheme of data pattern classification is proposed. On this basis, the pattern classification model of dam safety monitoring data is established based on convolutional neural network. The case study shows that the proposed algorithm performs well in pattern classification of monitoring data. Compared with previous methods, this method has the advantage of using one model to accurately and quickly process massive and multi-type monitoring data without artificial definition of mathematical model. This research is the extension of application of the new generation of artificial intelligence technology in the field of dam safety, which is also the key technology to realize intelligent management of dam safety.

Based on design review, the typical problems in design of safety monitoring for small reservoirs were systematically summarized, including inadequate capability of design organization, omission of important design content, incomplete design-related basic information, improper utilization of existing safety monitoring equipment, design divorced from engineering practice, confusing set of important and unimportant monitoring items, and et al. It is proposed that the quality management of safety monitoring needs to be enhanced in aspects such as more attention paid to the design, improvement of guidance and training, strengthening of design inspection, special focus on safety monitoring design of reinforced and newly-built small reservoirs.

There is a lack of safety and emergency management system and mechanism for cascade hydropower stations in China. To prevent and respond to safety emergencies of dams in the upper reach of Yellow River basin, and to control, mitigate and eliminate adverse effects of emergencies, study on the safety and emergency management of 13 hydropower stations in the reach from Longyang George to Liujia George was carried out by State Power Investment Group Huanghe Hydropower Development Company Limited. The analysis of risk classification matrix and the theory of risk prevention were used to establish the dam safety and emergency management mechanism suitable for hydropower stations in the upper reach of Yellow River belonging to different owners. The study results were of great importance and worthy reference.

This paper analyzes the cause reasons for reservoir diseases. In view of the problems of small reservoirs, such as large number, scattered locations and serious diseases, as well as the new situation and new requirements for reservoir reinforcement at present stage, including the focus on solving the weak links of flood control, preventing and coping with sudden and extreme risks, and promoting high quality development, this paper puts forward countermeasures and suggestions to solve the problems, which provides a useful reference for speeding up the reinforcement of reservoirs and promoting the high-quality development of water resources.

A monitoring information reporting system based on Beidou SMS communication for hydropower stations is designed. This system collects the monitoring data of hydropower station from Beidou high-precision sensors in real time under emergency conditions and sends them to the dam safety supervision platform of National Energy Administration through Beidou short message communication, thus reliable conditions for getting insight into the operation of hydropower dam under extreme weather are created.