Hydrogeochemical characterization of groundwater in the Nekor-Ghiss plain, Morocco

Abstract

The coastal Nekor-Ghiss aquifer, located on the northeastern Mediterranean coast of Morocco, constitutes an essential freshwater resource for the city of Al Hoceima, supplying water for agriculture and domestic use across an area of approximately 100 km 2 . This study provides a comprehensive hydrogeochemical characterization of 25 groundwater samples collected in May 2022, combining physico-chemical analyses with Piper diagram classification to identify dominant water facies and sources of contamination. The results show that the waters are highly mineralized, with electrical conductivity ranging between 1825 and 12720 µS/cm. Three distinct hydrochemical facies were identified: a predominant sodium chloride (NaCl) facies (84%) and a sodium sulfate facies. Marine intrusion and evaporite dissolution particularly affect wells W16 and W17, as evidenced by their high concentrations of Na + (2572.8 mg/L) and Cl - (3961.8 mg/L). Agricultural contamination was detected in well W21, where nitrate concentrations exceed the WHO limit of 50 mg/L, while well W23 shows critical nitrite pollution (25.56 mg/L), indicating localized contamination. This study highlights the complex interactions between natural geochemical processes and anthropogenic pressures in Mediterranean coastal aquifers and provides essential baseline data for implementing sustainable groundwater management strategies in the region.