On the hydrologic-hydraulic revaluation of large dams

The aim of the present work is to develop a criteria to evaluate the safety level of large dams. This is executed by comparing the discharge capability of a dam with the peak flow estimates, with respect to 100-, 200-, 500-, and 1000- year return periods. The methodology consists of estimating the intensity duration frequency (IDF) curves, starting from observational time series, collected by rain gauges. Then, through a rainfall-runoff transformation, the design hydrographs are obtained for different return periods. The results are compared to trends of peak discharges, obtained previously by the handler of the dam. It can be noted that, if the basin area is smaller than 1 km2, the peak discharges estimated are always lower than those calculated by the handler, regardless of the antecedent moisture conditions (AMC) assumed. Otherwise, the peak discharges obtained by the handler range between those we obtained for AMCII and AMCIII.