Numerical modeling of seawater intrusion in the Sahel region of the Atlantic coast of Morocco

A numerical study is being undertaken to investigate the occurrence and to assess the importance of saltwater intrusion in the Sahel region along the Atlantic coast of Morocco. The zone, which extends from the cities of Safi and el Jadida for about 100 km in length, is an important agricultural plain where groundwater is heavily used as an irrigation supply. In 1994 a study [DHRT, 1994] conducted by DRHT in collaboration with FAO was completed to evaluate the impact of pumping on the salinization of the aquifers and to define a proper exploitation scheme. A database was built up containing hydrogeological site characterization, monitoring and exploitation data from a network of 30 wells, and geophysical estimates of the saltwater-freshwater interface depth. These data were used to implement a two-dimensional groundwater flow model using MODFLOW software [McDonald and Harbaugh, 1988]. The major hydrodynamic features of the site were adequately captured in these simulations, but because a static saltwater-freshwater interface was assumed, coinciding with the aquifer bottom, the freshwater outflow to the sea wa