Analyse fréquentielle et modélisation statistique des crues cas du bassin versant « Isser Sekkak »

Abstract

Floods are one of the most significant hydrological phenomena due to their impacts on populations, infrastructure, and the environment. The knowledge of extreme flows is essential for the design of hydraulic structures and the management of flood risk. In this context, this work focuses on the frequency analysis and statistical modeling of floods in the Isser Sikkak watershed based on the available hydrometric data. The study consisted of analyzing a series of daily maximum rainfall to evaluate its statistical characteristics and quality. Several probability distributions were fitted to the observed data, including the Gumbel distribution and the log-normal distribution. The quality of the fit was evaluated using the AIC and BIC criteria as well as the Chi-squared and Kolmogorov-Smirnov statistical tests, using the Hyfran Plus and Hydrognomon software. The results obtained allowed for the identification of the most appropriate probability law to represent the behavior of the rainfall in the studied basin. Subsequently, the analysis of short- duration precipitation allowed for the construction of the IDF curves. The interpretation of the results shows that the Sokolovsky method is the most appropriate for estimating the maximum flows of the Oued Isser sikkak basin corresponding to different return periods, such as 10, 20, 50, and 100 years. These estimates provide essential information for the design of hydraulic structures and the assessment of flood risk. Finally, this study highlights the value of frequency analysis as a decision-making tool in the field of hydrology. The results obtained could be utilized in future work on hydraulic modeling and flood zone mapping.