ABSTRACT
Dams are among the greatest human achievements, and their history dates back to 3,000 BC.
There are over 800,000 dams in the world; more than 57,000 dams have been classified as large dams (as per ICOLD classification). China has the world’s largest number of large dams, followed by the United States and India.
Although a dam failure has a very low probability of occurrence, there are severe impacts on lives and properties when these failures occur. Based on historic data, the average annual failure rate for dams is 10−4 and the probability of death per person living in a potential inundation area is in the range of 10−7 to 10−6.
According to statistics, 2,000 dams failed since the 12th century, 200 dams failed in the 20th century (outside China), and more than 17,000 people died because of dam failures.
As the world’s stock of dams gets older, and as the population living in potential inundation zones increases, both the rate of dam failures and the probability of fatalities will increase unless effective dam safety measures are implemented, including proper dam inspection, safety assessment, operation and maintenance, implementation of safety rehabilitation works, and emergency preparedness.
