NOVEL APPROACH TO ESTIMATE RUNOFF IN SEMI-ARID AREA. CASE STUDY OF THE BASIN OF OUED DJELFA-Melah (ALGERIA)

Abstract

The critical hydrological situation in semi-arid area vs. the problem of availability of water resource , let us to think about application of new method to assess the surface runoff for purpose of establishment the hydrological water of a hydrological system. The quantification of annual flows is paramount to assess the surface water resources. A new model was developed based on three parameters to the time of concentration, precipitation and the shape compactness index of the watershed. We have simulate the average annual runoff for a random observed precipitations, the result obtained are compared to several empirical formulae used for the evaluation of runoff. Its performance is evaluated by the criteria of Nash, RSME, and MAE. This model has been tested and applied in the basin of Djelfa which characterized by a semi-arid climate, the average annual runoff calculated for the region for shape index of 1.41 and concentration time of 13.41 hours is about 9 mm. The high part of runoff was losted by the Eavpotranspiration and by the infiltration