Problem of upwelling, salinity and nitrate pollution of the Beni-Amir groundwater (Tadla, Morocco)

Abstract

The phreatic aquifer of the Beni-Amir irrigated area (Tadla, Morocco) is a plio-quaternary heterogeneous reservoir. Human activities and natural recharge variations have direct effects on temporal groundwater level fluctuations. Indeed the irrigation process of the Beni-Amir area, has led to groundwater table rise problems. Hence, several thousands of hectares of this area have been flooded from groundwater table rise ; afterwards groundwater and soil quality become deteriorated due to their salinisation. In this work, we present a hydrogeological analysis and characterisation of the study area: hydrodynamic parameters, space and temporal piezometric variation in order to characterise the hydrogeological behavior of the aquifer system. The results show that the groundwater table rise is directly due to the recharge from irrigated water and irrigation practices, in addition to a no suitable water drainage system. The piezometric maps show that two zones are permanently affected by the groundwater table rise problem. A diagnosis of groundwater pollution by salt and nitrate accumulation has shown a net deterioration of groundwater quality due to the practices of the irrigation management and fertilizers, in addition to groundwater recycling from pumping wells.