Contribution of the spatial variability of basin physical characteristics in hydrological rainfall-runoff modeling and by-products of hydrological balance: Case of Lower Mekerra watershed, Algeria
Technological advances in the acquisition of spatial data offer the possibility of taking into account the spatial distribution of the watershed physical characteristics in hydrological modelling. In order to do this, we have chosen to compare the performances of a semi-distributed hydrological model SWAT (Soil and Water Assessment Tool) and a global reservoir model GR4J (Rural engineering model with four daily parameters) in the Lower Mekerra watershed. For these two models, rain and temperature data are the same, the difference is how they consider the various processes of the hydrological cycle in interaction with the physical characteristics of the basin. The semi-distributed approach seems to give slightly better results than the global approach for the case study. This is probably due to the spatialization of the physical characteristics of the watershed as well as to a better representation of the hydrological transfer function in the SWAT model. This study highlights the interest of remote sensing and geographic information system (GIS) in the ease of introducing the physical characteristics of the basin for optimal use of model capacity. Moreover, the results found show the interest of using the SWAT model without claiming its superiority because it can offer convincing results for some cases like our basin and be less efficient for others.