Initial results of sediment yield measurement interpretation using a regional approach: Southern Italy case study

Abstract. The theoretical TCEV (Two Component Extreme Value) distribution was applied to interpret the sediment yield datasets available in Southern Italy. The analysis is based on hydrological data collected for twelve catchments located in Calabria and Basilicata. A hierarchical approach was used to obtain a regional parent distribution which was used to determine the return time for each event. The hierarchical approach proposed in this study includes two stages. The first stage served for calibration and made it possible to estimate the parameters of the theoretical TCEV distribution. More specifically, the hypothesis of homogeneity with regard to the skewness coefficient and the coefficient of variation was verified using the datasets related to nine catchments. The second stage consisted in verifying the goodness of the theoretical distribution on three independent datasets provided by three experimental catchments not involved in the calibration. Overall results show that, even if the TCEV distribution was conceived to estimate peak flow, its concept of “double component” can be extended to predict sediment yield on a regional scale.