Statistical Hydrology

Hydrological phenomena such as precipitation, floods, and droughts are inherently random by nature. Due to the complexity of the hydrologic system, these physical processes are not fully understood and reliable deterministic mathematical models are still to be developed. Therefore, in order to provide useful analyses for designing hydraulic facilities and infrastructures, statistical approaches have been commonly adopted. This chapter describes some statistical topics widely used in hydrology. Among the large number of subjects available in literature, the attention is focalized on some of them particularly useful either for innovative hydrological analyses or for an appropriate application of common procedures. Precisely, the chapter describes in details the stationary hypothesis on hydrological time series, the univariate extreme value analysis procedure, the intensity–duration–frequency curves, the copula function useful for multivariate analysis, and the regional flood frequency analysis. Author Keywords: Copula function; Extreme rainfall analysis; Extreme value analysis; Goodness-of-fit tests; IDF – intensity duration frequency curves; L-moments; Multivariate distributions; Nonstationary time series; Regional index flood; RFFA – regional flood frequency analysis; Time series segmentation; Trend detection