Use of graphical and multivariate statistical methods to show a marine intrusion and salinization of a coastal water table: case study of the township of Abomey-Calavi, Benin

A robust classification scheme for partitioning water chemistry samples into homogeneous groups is an important tool for the characterization of hydrologic systems. In this paper we test the performance of the many available graphical and statistical methodologies used to classify water samples including: Piper diagram and diagram of Schoeller and Berckaloff. All the methods are discussed and compared as to their ability to cluster, ease of use, and ease of interpretation. The combination of graphical and statistical techniques provides a consistent and objective means to show that groundwater in the district of Godomey in the municipality of Abomey-Calavi is contaminated by sea water. This study reveal Togbin to be the area of intrusion of seawater into groundwater. This study has helped in setting the boundaries where seawater intrusion into groundwater occurs in the township of Abomey-Calavi. These results confirm the findings of Boukari et al., in 1996, who detected an early saline intrusion in this Godomey pumping area.