Abstract: China has the largest number of dams in the world. Reservoir and dam safety involves the public safety with high cost for safety management. Governments at all levels have paid increasing attentions to differentiated dam safety management, which is worthy of research as current safety management no longer meets governments' requirements in reservoir and dam safety. Based on the concepts of dam fragility and dam-break consequence coefficient, we analyzed the method of calculating dam risk index, modified the dam-break consequence coefficient, and apllied the modified method to 20 earthquake-damaged reservoirs to obtain the ranking of dam risk index. Results show that the risk index of highly vulnerable reservoir is not necessarily high, and vise versa. Fragility is not the only dependent variable in determining the risk index. Fragility and dam-break consequence coefficient must be combined to determine the risk index. Dams with high risk index should be reinforced in priority.

Key words: dam safety, fragility, dam-break consequence coefficient, risk index, ranking method