A numerical approach to groundwater catchment protection perimeters

We established isochrones, considered as an intermediate protection perimet ers, from travel time, using advanced hydrogeological and numerical models of catchment sites. This consists of the resolution of flow and transport e quations using a finite volume elements scheme. Our simulations have shown that the real dimensions of the intermediate protection perimeter depend on the parameters of dispersion. Finally, the application of this method to t he Ahmed At-Taleb site in northwest Morocco illustrates the urgent need for an adequate protection of catchments from very dangerous pollutant agents. ((C) Academie des sciences / Elsevier, Paris.).