DETERMINATION DES CRUES DE PROJET PAR LES ASPECTS DU DEBIT DE POINTE ET DE L’HYDROGRAMME DE CRUE AU NIVEAU DE LA COMMUNE AIN BOUKELLAL, BASSIN VERSANT DE L’OUED LARBAA, MAROC

The peak flow of a flood can be determined by several empirical methods. Among these methods, the method of Gradex is used in this work for the estimation of the design flood and volumes corresponding to the flow. This approach has allowed recognizing the flow of different frequencies by the aspects of peak flows and the flood hydrogram. The study was based on the annual maximum daily rainfall for a long series of observations (49 years), and the curves of the intensity-duration-frequency (IDF) of Taza rainfall station located in the watershed the Oued Larbaâ. The application of the Gradex method allowed to approach the maximum flood at the level of Ain Boukellal rural county for the frequency of rare occurrence (return periods ranging from 10 to 1000 years)