Badr Layan, Abdallah Dridri, L
Determination of Design Floods by Aspects of Peak Flow and Flood Hydrograph in Watershed of Larbaâ River, Taza (Morocco) The major task of a hydrology study is to compute the design flow. There are conceptual and empirical methods for computation of design flow. The following paper shows the Gradex method estimating the design flood and the volumes corresponding of flows. This approach allowed us to know the design floods by aspects of peak flow and flood hydrograph. The study is based on long series of observations (49 years) of the annual maximum daily rainfall, and the Intensity-Duration-Frequency curves of the raingauge station of Taza located in the Larbaâ catchment. The Gradex method aims to find the maximum flow of floods for the rare frequency of occurrence (return time over 100 years). Hence, we attempted to explains why and how the combined use of rainfall and floods of different sub-catchments of Larbaâ River.