There are currently more than 98,000 reservoirs of various types in China, which have played an irreplaceable role in safeguarding the national water security. However, most of the reservoir dams were built between 1950s and 1970s, with prominent safety problems. Since 1950s, more than 3,500 reservoir dams have breached, resulting in huge losses. Remarkable effects of diseased reservoir dam rehabilitation implemented since 2000 have been achieved. Yet occasionally there are dam breaches, which mean that dam safety and risk management are comparatively week.
Therefore, Nanjing Hydraulic Research Institute, China Institute of Water Resources and Hydropower Research and other 8 institutions jointly conducted a 10-year research project in view of 4 scientific issues of dam breach and flood, dam risks, risk removal decision-making and emergent countermeasures, centering on the key technology of safeguarding reservoir dam safety and supported by National Key Technology Research and Development Program during the 11th Five-Year Plan, Research on Safeguarding Technology of Reservoir Dam Safety (Grant No. 2006BAC14B00), international science and technology cooperation project of MoST, and the State Key Program of NSFC.
1.Major Innovative Achievements
Compared with similar technology both at home and abroad, major breakthroughs in multi-technical indexes and theoretic methods were made with a series of innovative achievements obtained by this project, filling the domestic gaps.
1.1 Dam breach experiment and simulation technology
By setting up a prototype dam breach experiment field with the highest dam crest of 9.7m both at home and abroad (the highest dam crest abroad: 6.0m), a multi-factor dynamic fine measurement system was developed for such kind of dam breach experiment. New phenomena in the process of earth-rock dam breach were found. New mechanisms of shearing erosion, undermining by dual spiral flows and intermittent unsteady collapse of breach slopes were disclosed for earth-rock dams. Similarity criterion of overtopping breach modelling and prediction method of breach development were established. Hence, dam breach theory and simulation method were completed.
1.2 Basic database and data mining of dams
The basic full-range and all-factor database of reservoir dams in China was set up for the first time. A technical standard of reservoir dam information acquisition was created. The aging evaluation model and assessment index system were built up by systematically excavating the causes and evolution mechanism of diseased reservoirs. A statistic model of multi-parameter dam breach features was constructed by revealing the temporal and spatial characteristics and rules of dam breaches in China.
1.3 Dam risk management technology
A generalized model of individual risk bearing capacity was set up for the first time, and so was a risk criterion system of reservoir dams in China. Grading Standard of Reservoir Dam Risks and Assessment Guideline of Reservoir Dam Risks were worked out. A whole process decision-making method and assessment model for diseased reservoir rehabilitation were innovatively established. The identification criterion of reservoir degradation and abandonment was proposed. A network layered analysis model of impacts of reservoir dam demolishing on and restoration of eco-environment was built up. Standard of Reservoir Dam Degradation and Abandonment was compiled.
1.4 Dam safety monitoring and early warning technology
A typical atlas and new data analysis method of hidden dam diseases were raised. A new model was developed to identify the dam safety monitoring data reliability and predict dam safety, and so was a comprehensive analysis and inference system of dam safety based on artificial intelligence technology. The classification standard of early warning for emergent events of reservoir dams was forwarded for the first time. Thus an early warning indicator system of emergent events of reservoir dams was established.
2.Academic Outputs and Third Party Evaluation
The project had rich academic outputs, including 22 patented technology, 24 industrial standards and codes, 14 monographs or translated books, 315 papers and 17 sets of software. In 2014, the project passed the appraisal organized by MWR with a conclusion that the overall research findings had reached the international leading level. And the research findings won the 1st Prize of the National Science and Technology Progress Award in 2015 and the unique Special Prize of Dayu Water Science and Technology Award in 2014.
A number of talents were fostered via this project. One of the main researchers was elected as the member of the Chinese Academy of Engineering, many listed in various talents programs, and more than 100 students trained for master or doctor degrees. An independent innovative research base for safeguarding technology of reservoir dam safety was established.
3.Application Promotion and Comprehensive Benefits
The research findings have been successfully applied in more than 50 large-scaled reservoirs, such as the Xiaoliangdi Reservoir, the Xiaowan Reservoir, the Danjiangkou Reservoir, the Fengman Reservoir, etc., playing an important role in national diseased reservoir dam rehabilitation, water census and emergency responses to reservoir accidents, and promoting the industry scientific and technological progress. The project findings were highly appraised by the World Bank, the Swiss Energy Agency, the Royal Dutch Academy of Engineering, the Office of State Flood Control and Drought Relief Headquarters, the Ministry of Water Resources, the National Energy Administration, local water administration departments, design units, and reservoir operation management units. The research findings can be popularized in the dam safety management of nearly 100,000 reservoirs in China with a bright prospect of application.
The research findings mainly serve the national reservoir dam safety management and practices with great safety, social, economic and eco-environmental benefits. In view of national reservoir dam rehabilitation, the research findings generated economic benefits of RMB13.4 billion during 2012-2014. Definitely, more remarkable were social benefits, as the research findings have greatly reduced the probability of dam breaches in China, and essentially eliminated life losses caused by dam breaches.