This work aimed to adjust and compare the parameters (K, a, b and c) of the intensity-duration-frequency equations of the maximum rainfall taken from 133 rainfall stations located in the state of Piauí in Brazil, which are available from the database of the National Water Agency - ANA. The stations were initially chosen by analysis of the consistency of the data series, and then from these, 105 rainfall stations were then selected. The maximum rains for one day were separated into durations of 5, 10, 15, 20, 25, 30, 60, 360, 480, 600 , 720 and 1440 minutes and the maximum rainfall estimated using probabilistic models for each duration and each return period of 5, 10, 25, 50 and 100 years. The parameters (K, a, b and c) were then adjusted by means of both linear and nonlinear regression. The adjustment of the parameters of the intensity-duration- frequency equation for maximum precipitation, carried out using nonlinear regression, had R² (0.99) higher than the values adjusted using linear regression (0.98).
Hydrology; Heavy rains; Return period
