A new seasonal design flood estimation method

Based on Copula function,a bivariate joint distribution which considers the flood occurrence dates and magnitudes of the peaks-over-threshold(POT) sampling series was established.A new seasonal design flood estimation method was proposed and compared with current methods.Case study results show that the proposed method could satisfy both flood prevention standard and the relations between the annual and seasonal design floods.The seasonal design floods estimated by the proposed method are slightly greater than annual design floods in the main flood season and less in other flood seasons.The proposed method is superior to current methods and provides a new way for seasonal flood estimation.