Modeling Intensity-Duration-Frequency Curves for the Whole Range of Non-Zero Precipitation: A Comparison of Models

Intensity-duration-frequency (IDF) curves are useful in water resources engineering for the planning and design of hydrological structures. As opposed to the common use of only extreme data to build IDF curves, here, we use all the non-zero rainfall intensities, thereby making efficient use of the available information. We use the extended generalized Pareto distribution to model the distribution of the non-zero rainfall intensities. We consider three commonly used approaches for building IDF curves. The first approach is based on the scale-invariance property of rainfall, the second relies on the general IDF formulation of Koutsoyiannis et al. (1998, ), and the last approach is purely data-driven(Overeem et al., 2008, ). Using these three approaches, and some extensions around them, we build a total of 10 models for the IDF curves, and then we compare them in a split-sampling cross-validation framework. We consider a total of 81 stations at 10 min resolution in Switzerland. Due to the marked seasonality of rainfall in the study area, we performed a seasonal-based analysis. The results reveal the model based on the data-driven approach as the best model. It is able to correctly model the observed intensities across duration while being reliable and robust. It is also able to reproduce the space and time variability of extreme rainfall across Switzerland.

Automated summary

Intensity-duration-frequency (IDF) curves are important for water resources engineering. We use all non-zero rainfall intensities and the extended generalized Pareto distribution to model their distribution. We compare three approaches for building IDF curves and find that the data-driven approach is the best model. It can accurately model observed intensities, is reliable and robust, and captures space and time variability of extreme rainfall in Switzerland.