Abstract
This study presents the 1(st) method Parfait-Hounsinou, a method that makes it very easy to detect saltwater intrusion in groundwater. The method relies on the commonly sampled ion concentrations. This method involves several steps, namely: Chemical analyzes to determine the concentrations of majors ions and TDS in groundwater, production and study of the spatial distribution of chemical parameters in groundwater (TDS, Cl(-)…), delimitation of a probable area of saltwater intrusion in groundwater and the production and the study of spie chart where area of pie slices represents ions contents or group of ions content in the groundwater sample of the probable area of the saltwater intrusion in groundwater and radius length represents the Relative Content Index. The method is applied to groundwater data collected from the municipality of Abomey-Calavi in Benin. The method is also compared to other methods used for saltwater intrusion including the Scholler-Berkaloff and Stiff diagrams and the Revelle Index. Comparatively to Scholler-Berkaloff and Stiff diagrams, the 1(st) method Parfait -Hounsinou, at spie chart level, the area of pie slices make it easier to compare the major cations between them and the majors anions between them and the Relative Content Index of the chloride ion allows further confirmation of the saltwater intrusion and its extent.•There are frequent saltwater intrusion into groundwater which are important freshwater reserves for our planet.•Governments around the world should delineate the levels of ocean intrusion into groundwater using scientific methods such as this method and seek to limit this saltwater intrusion.•In this article we have proposed a simple and reliable method based on a series of irrefutable proofs of saltwater intrusion into groundwater.