Author(s): Huong Nguyen Lan; Mao Nguyen Van; Bao Nguyen Huu
Linked Author(s):
Keywords: Dam safety; Environment management; Probabilistic
Abstract: Recently, dam safety has become not only an issue of the countries where many dams and reservoirs were built, but also the global concern. Depending on the natural conditions, geographical circumstances, economic potentials, sciences and technology different nations applied different approaches to dam safety. In Vietnam, there are about 2360 big and small rivers, 14 large river basins, including many international rivers plus above3200 km coastal bank. In average, annually Vietnam has been suffered directly from 6-7 storms and tropical depression. There were outstanding issues in natural environment management in Vietnam, such as forest cutting, unplanned construction of reservoirs, weaknesses in upstream water resources exploitation management as flood operation in international rivers, and so on. Besides, Vietnam is one of the countries that are suffered seriously from climate changes, therefore, more and more indefinite negative factors of dam safety in Vietnam have been identified. Vietnam has about 2600 reservoirs which storage capacity is about 0.2mil. m3 and above, built in different periods, under different technical and investment levels and managed with asynchronous and changeable standards. Quality of headworks that formed existing reservoirs was diverse and being degraded seriously without repairs. Equipment and technology required for monitoring, forecasting, alarming of dam and downstream safety were insufficient and of low level. Dam safety management in Vietnam has been authorizing over two state levels while for reservoirs and dams the management was undertaking within their territory and basin-wide management appeared limited. Calculations for reservoir and dam designs as well as for dam safety analysis in Vietnam have been following deterministic design model. Legal documents related to dam safety operation was no synchronous and stable. Complexity of deterministic factors of natural environment has been increased day by day, the existing management as well as design model showed many inadequacies. Therefore, Vietnam needs advanced steps in dam safety sciences and technologies. The article presented analysis of relevant problems of dam safety and some initial results of the researches for developing probabilistic design in dam safety analysis under Vietnam conditions. Dam and headworks safety analysis results with data collected in some works recommended the applicability of problems with probability level II in dam safety sector in Vietnam. The researches provided grounds for calculation of probability of water overtopping with Monte Carlo method, the article gave comments on approach to Monte Carlo method in dam safety analysis and it’s initial step for solving the probability problem level III. The article showed new researches on modern design models that helped to improve quality of dam safety analysis in Vietnam.
Year: 2014