Case Study: Risk Analysis by Overtopping During an Upstream Landslide in Peñitas Dam, Mexico

Abstract. Risk and uncertainty analysis by mathematical and statistical methods is often used to assess systematic risks and uncertainties. This research presents the procedure and application of risk and reliability analysis to dam overtopping (Peñitas) located downstream of a natural dam that could have failed. For the analysis are used six statistical variables and their uncertainties, the peak flood of the upstream dam, are evaluated with empirical formulas. The highest water levels of the break dam event were computed using reservoir routing with an explicit equation developed by the authors. Afterward, the overtopping risk analysis of Peñitas Dam was assessed for different stages of excavation of the natural dam that were made during making a sensitivity analysis of duration of dam break event, and also is calculated the possible upper elevation of Peñitas dam, finding that is a recommended practice measurement in similar further cases. A methodology to do an orderly and consistently analysis of risk is proposed to solve similar situations.