SIMULATIONS OF SOME SCENARIOS OF DECONTAMINATION OF ANTHROPOGENIC NITRATE IN GROUNDWATER OF BERRECHID (MOROCCO)

The Berrechid water table is very vulnerable to pollution from the soil surface. This pollution can be either localised (domestic and industrial wastewater discharges, solid waste leached by infiltration) or diffuse (spreading of fertilisers on the soil, treatment of crops with plant protection products). This last mode of contamination presents the danger of spreading over large areas and therefore being difficult to control. To model nitrate transport in the Berrechid aquifer, we used the MT3DMS model coupled with the hydrodynamic model previously created using MODFLOW; this in order to have numerical tools for an optimal management of the groundwater resources of the region. Different simplified water management scenarios are examined, in particular artificial recharge and reduction of pumping water volumes for irrigation. The results show that halving current withdrawals would improve the current situation of the Berrechid aquifer by avoiding the appearance of dewatering zones in 2028, with a considerable decrease in nitrate concentrations in almost the entire aquifer. The model we have developed could therefore be an effective tool for quantitative and qualitative management for the decontamination of groundwater in the Berrechid aquifer.