SUMMARY
This work is also intended to simulate the flows of the studied Macta sub-basins by using a modified version of Schreiber's multi-year hydrological model to determine the evolution of the climate index as a function of the aridity index. Optimizing the parameter of the model will allow us to determine the extent to which the climate explains the trends in annual flow chronicles. Indeed, the evolution of the aridity index as a function of the climatic index in the 1st and the 2nd sub-period of flow series demonstrates the role of climate behavior on hydrological behavior and the influence of other factors. A multi-year hydrological modeling using Schreiber's formula shows a variation of the parameter of the Schreiber formula between 1975 and 2005 and the definition of its optimal value will depend on the mean squared error (RMSE). which will be used in hydrological modeling of basins.