Characterization of a ground water hydrochemical system through multivariate analysis: Clustering into ground water zones

Multivariate data analyses were performed with the hydrochemical data from a small area in Incheon, Korea. Previous studies based on hydrogeological and hydrochemical observations proposed that the ground water hydrochemical system of the site is governed by two distinct hydrochemical regimes. Each of the two regimes governs a ground water zone, zones A and B, The ground water in zone A is characterized by confined aquifer conditions and low values of dissolved oxygen (DO), NO3-, SO42-, Na+, Cl- and Mg2+, without much seasonal fluctuation in chemical properties. On the other hand, the ground water in zone B is characterized by unconfined aquifer conditions, relatively higher DO and NO3-, and higher, but seasonally variable, Na+ and Cl-, The hydrochemical data used for the interpretation of the previous studies are employed for factor and cluster analysis. Major factors are interpreted as correlates of chemical processes. Factor scores are computed and the cluster analysis is performed using factor scores. The zones discretized from the cluster analysis have the same distribution pattern as the zones delineated in the previous studies. The factor scores and the cluster analysis results also imply seasonal variation of the ground water hydrochemical system.