The Assessment of Heavy Rains in the Region of Annaba (NE Algeria) to Improve Extreme Flood Forecasting—Use of Depth-Duration-Frequency Curves

Abstract

Abstract:The knowledge of space and time distribution of short duration rainfall depths is of primary interest in hydrotechnical studies and in extreme floods modelling. This work is carried out to establish a "DDF (Depth-Duration-Frequency)" relationship for the region of Annaba (Northeast of Algeria) through the examples of Pont Bouchet (El Hadjar), Ain Berda and Chafia-Dam rainfall gauges. The results of the frequency study of stochastically generated annual series (Pearson's distribution type III model) and the regression analysis (least square method) permitted to develop a master curve that well describes heavy rainfalls distribution in the Annaba region. This 2-parameter model is used to predict, with sufficient accuracy, the amount of rain that could be recorded over a shorter duration from daily rainfall data in basins that lack recording rain gauges.