The plate of phosphate is a geographical zone distributed between three basins slopes: The catchment area of Oum Rbia, the catchment area of Mallah Wadi and the basins slopes of Chaouia. These basins slopes are located in Morocco power station. They are thus exposed to disturbed oceanic flows coming from North and of Western North. The basins slopes of Chaouia and particularly those of the plate of Settat-Ben Ahmed are characterized by a little developed hydrographic network. It is hardly made up by the ends down streams of the wad is going down from the plate. These water ways, not having a discharge system towards the sea, they cross the plain of Berrechid on about ten kilometers before atrophying itself there. They are with temporary flow, their water arrive on the plain, they are then evaporated or percolate towards the tablecloth, therefore one speaks about a endoreic hydrography.

The area of the plateau of phosphates, and the plain of Tadla which extends over an area of 12300 km2 in Morocco central, is very well known for its interests industrial, economic and social very important. The groundwater resources in waters that is more vulnerable to overexploitation and/or to the alteration. The aquifer system is present in the coverage meso-Cenozoic and quaternary which has deposited on the Paleozoic formations. The modeling of the hydrodynamic functioning of this multilayered system allows the understanding and monitoring of the hydrogeological balance sheets, it is in the heart of the management of resources and their preservation. This work aims at the finite difference modeling the multi-layered complex of the plateau of phosphates and the plain of Tadla, the application adopted for the realization of the modeling is the GMS (Groundwater Modeling System of Aquaveo) with the Modflow code (U.S. Geological Survey) which have proved flexible enough for the design and the manipulation of the modeling. The conceptual model is composed of 4 bunk aquifers. The rivers of Oum Errabia, Derna, Laabid and Tassawout rivers form the main drains in the model, as-the climate inputs combined with the surplus water after irrigation of the perimeters of Tadla, without evaluated by the model of the hydrological balance "Wetspass" and form the main resource of the recharging. From the results of the timing of the model of the aquifer system "in whole" it may be pointed out its flexibility to reproduce the water operation of a complex system and multi-layered. The Oum Errabia, Derna, Laabid and Tassawout rivers form the main drains in the model, inputs are represented by climate apport combined with the surplus water after irrigation of the perimeters of Tadla without evaluated by the hydrological balance model "Wetspass". From the results of the calibration of the "entirely" aquifer system model we can see flexibility to reproduce the hydrological functioning of a complex and multi-layered system.