USING THE TCEV DISTRIBUTION FUNCTION WITH SYSTEMATIC AND NON-SYSTEMATIC DATA IN A REGIONAL FLOOD FREQUENCY-ANALYSIS

Due to the social and economic implications, flood frequency analysis must be done with the highest precision. For this reason, the most sui table statistical model must be selected, and the maximum amount of in formation must be used. Floods in Mediterranean rivers can be produced by two different mechanisms, which forces the use of a non-traditiona l distribution like the TCEV. The information can be increased by usin g additional non-systematic data, or with a regional analysis, or both . Through the statistical gain concept, it has been shown that in most cases the use of additional non-systematic information can decrease t he quantile estimation error in about 50%. In a regional analysis, the benefit of additional information in one station, is propagated to th e rest of the stations with only a small decrease with respect to the at-site equivalent analysis.