Method to Establish Intense Rainfall Equations Based in Geoprocessing

The knowledge of heavy rainfall is essential for watershed management and hydraulic structure design. Heavy rainfall is characterized by an equation derived from sub-daily rainfall series that relates the rainfall’s intensity, duration, and frequency (IDF equation). This paper proposes a geoprocessing model to obtain the parameters for the IDF equations for places without rainfall data. IDF equations, from the literature, were used to obtain maximum rainfall intensity (i_m) for 96 combinations of durations and return periods. These i_ms were spatially interpolated, and the IDF parameters were established for each pixel through non-linear multiple regression. The performance of three different interpolators (inverse distance weighting, Kriging, and random forest) was evaluated. The analysis showed that spatialization by inverse distance weighting had the best performance to establish IDF Eqs. (3% of mean absolute percentage error), followed by random forest (8%) and Kriging (16%).