The Likelihood of a failure of a damming structure

Having an analysis of real breakdowns and damages in Polish damming structures as a basis, and assuming the probability of controlling freshet as a unit, one can calculate the probability of failure of a hydro-technical structure, due to failure of the base, the draining system, anti-filtering safety appliances, the body or the abutments. The results obtained af-ford an estimation of failure risk at any moment of the structure's opera-tion and an estimation of the overall failure probability. The calculations were carried out for all dam classes. When the dam's elements are in good condition, the overall failure probability is by one order of magni-tude greater than the probability that a controlling freshet will occur.