Alternative method to evaluate design storms

An alternative approach to the definition of a project Design Storm that does not require prior definition of the IDF curves for the site under study is presented. The procedure is based on a two-peak hyetograph that allows a better fit to observed maximum annual events. The approach requires estimation of six to eight parameters, which are based on the historic records of maximum annual events for a given duration. The study concentrated on convective events with a duration up to three hours which have produced the largest peaks in the Ligurian region. Preliminary results show that some of the parameters remain constant for the region, thereby facilitating the estimation or regionalization of the others. The impact of alternative definitions of the design storm on the design hydrographs is evaluated.