Performance of parametric intensity-duration-frequency models in the study of intense rainfalls

Abstract

Intensive rainfalls are characterized by their intensity (i), duration (t) and return period (T). The design rainfall used in hydraulic works design is determined using mathematical models of type i = f (t,T). This functional relationship is usually made by a potential non-linear multiple regression model, called the standard model. However, there are other models that have been poorly studied and may perform better than the standard model. Thus, this work aimed to evaluate the performance of seven mathematical models alternative to the standard model. Data of annual-daily-maximum rainfall for Cascavel, Paraná-Brazil, from 1975 to 2015, were used to derive the models. The rainfalls were disaggregated at intensities with return period ranging from 2 to 100 years and duration between 5 and 1440 min. The seven models studied were adjusted to the disaggregated values, as in the standard model. The best performances were from models 1 and 7, as their estimation errors in precipitation intensity were less than 5%. The worst performances were on models 5 and 6, which can generate errors greater than 40%.