Hydrochemical characteristics of aquifers from the coastal zone of the Essaouira basin (Morocco) and their suitability for domestic and agricultural uses

Groundwater hydrochemical of coastal aquifers (Plio-Quaternary, Turonian, and Hauterivian) of Essaouira basin, Morocco, was used to evaluate the groundwater quality for drinking and irrigation uses as well as to determine the processes controlling its mineralization. In this semi-arid coastal zone, The rock-water interaction (dissolution of evaporite and carbonate minerals) evaporation, reverse cations exchange, and seawater intrusion are the main processes responsible for the mineralization of groundwater and their facies. Water Quality Index (WQI), and sodium percent (%Na), sodium adsorption ratio (SAR), permeability index (PI), and Kelly index (KI) ratios were applied to assess the groundwater for drinking and irrigation uses. WQI shows that the groundwater is generally of poor quality and not suitable for direct usage and requires treatment before domestic use. Based on %Na, SAR, PI, and KI, the groundwater remains adequate for agricultural purposes. However, an attention should be accorded to groundwater salinization processes. The approach followed as well as the results of this paper remain valid for better and sustainable management of the vital resource within the Essaouira basin and similar basins.