Author(s): Rafael Antonio Briseño-Ramiro, Adrián Pedrozo-Acuña, José Agustin Breña-Naranjo, Víctor Hugo Alcocer-Yamanaka, Ramon Dominguez Mora

Linked Author(s): Ramón Domínguez

Keywords: Fragility curves; Probabilistic graphical model; Overtopping failure; Standard NMX-AA-175-SCFI; Flood mitigation;

Abstract: This paper shows the application of a methodology according to the standard "Dams Safety Operation" NMX-AA-175-SCFI-2015 to identify, estimate and evaluate the risk of earthen dam failure due to overtopping before and after the mitigation measures. Two methods were used: 1) the Event Tree Analysis (ETA); and 2) the Bayesian Network (BN) which was programmed in a model called @Dam_Risk. A homogeneous earth dam was analyzed that failed in its first filling (Feb 2010) due to a poor spillway design which had a failure probability of 7.23×10-2 for ETA and 1.16×10-2 for BN. It also placed 7.56×10-2 lives/year at risk and exposed the downstream population to $36,638.00 USD in material damage in the event of a failure. An alternate modification was proposed to mitigate the risk, it was then recalculated until reducing the probability of failure to 5.67×10-5 and 1.20×10-5, respectively. The event trees presented along with the help of experts' judgment serve to make a preliminary classification, afterwards, however, the @Dam_Risk model is recommended to carry out a formal risk analysis. The proposed methodology will permit the use of the Bayesian inference to obtain a fragility curve given the evidence of conditional probabilities for real cases of failure, so that the fragility curves according to type of dam can be categorized and used for assess the risk of a list of dams with like characteristics. It will also allow decision makers to compare the risks among dams in an equal way and propose alternatives until arriving at an acceptable risk.

DOI: https://doi.org/10.3850/38WC092019-1826

Year: 2019