Considerations on dam safety and the history of overtopping events

Several incidents with severe consequences have affected dams around the world recently. Some of them have caused dams to fail, and because of this concerns have been expressed. The concern is justified: the sudden liberation of thousands of tons of water over human habitation can cause a lot of human victims and material damage, including important effects to the environment. The industryʹs response is that dams "should not fail". Some agencies and owners of dams and hydroelectric power plants around the world have developed specific groups to solve these problems and to determine the required measures to be taken. In Mexico, several dams and hydroelectric power plants are nearing the end of their useful life; most of them were designed, constructed and assembled using standards that are not necessarily still valid. It is important to point out, for example, that many existing dams do not have the capacity to handle the types of floods that are considered now as design data, and they were not designed to resist earthquakes similar in intensity to those that recently occurred in Mexico and other sites of the world.