Actualization of the Qualitative State of the Water Resources in the Plain of Gharb (Downstream of Sebou - Morocco)

The Gharb plain ( Northern Morocco) benefits from a privileged geographical situation, very fertile soils, and relevant water resources. Geo-chemical characterisations of the groundwater and of the water-rock interaction processes are suggested. A shallow aquifer and a deep multi-layered aquifer have been distinguished. The shallow aquifer is hosted in silty clay formations, it supplies an alkaline-chloride type of water with the total dissolved solids (TDS) in the 0.7-1.8 g/l range, and the dissolved contents depend on the dissolution of sea salts, calcite, gypsum, and dolomite; salt domes leaching and cationic exchange or inverse exchange processes may occur locally, increasing the TDS up to 4 g/l. Less salty water ( TDS: 0.2-0.9 g/l) comes from the multi-layered aquifer, and shows a calcium bicarbonate composition related mainly to the interaction with carbonate minerals, which prevail in the sediments. All waters are over-saturated with respect to calcite, and under-saturated with respect to gypsum.