Assessment of seawater intrusion in an arid coastal aquifer, south-eastern Tunisia, using multivariate statistical analysis and chloride mass balance

Publication date: Available online 8 May 2018 Source:Physics and Chemistry of the Earth, Parts A/B/C Author(s): Faten Telahigue, Belgacem Agoubi, Faiza Souid, Adel Kharroubi Water availability is a fundamental concern for coastal areas in arid and semiarid regions such as Jerba Island, southeastern Tunisia. In these areas, the water demand is steadily increasing and putting pressure on water resources. These pressures are maintained by excessive pumping to meet the needs of various agricultural, domestic, industrial and tourism sectors. The effects on the groundwater are expressed by a quantitative and qualitative deterioration of the regional ecosystem. An assessment of groundwater salinization and seawater intrusion in Jerba aquifer are therefore needed. Physical parameters were measured in situ in one hundred and three boreholes and major ions were analyzed and several diagram were used to model groundwater mineralization. Geochemical analysis revealed that Cl-Na-Mg-Ca-SO4 was the dominant water type indicating rock-water interaction and saltwater intrusion. Na+/Cl−, Ca2+/Cl−, Br−/Cl−, Ca2+/Na+, Mg2+/Ca2+ and Cl−/HCO3 − ratios versus chloride confirms the double influence of mixing mechanisms of fresh and saline waters and the water-rock interactions. Computed seawater fraction for sampled water shows that the average mixing rate of seawater intrusion reached 10.5%, confirming the marine intrusion in the aquifer. The highest values were registered in coas...
Source: Physics and Chemistry of the Earth, Parts ABC - Category: Science Source Type: research