APPLICATION OF PRINCIPAL COMPONENTS-ANALYSIS TO THE STUDY OF SALINIZATION ON THE CASTELLON-PLAIN (SPAIN)

The high salinization in some sectors of the Castellon Plain aquifer ( Spain) has been erroneusly attributed to seawater intrusion, because o f the high and increasing contents of chloride ions. However, recent s tudies of this aquifer have shown that the chemical characteristics of groundwaters are the result of three different components: intruding seawater, freshwater from rainfall infiltration and saline water with a characteristic sulphate-calcium-magnesium facies, derived from borde ring aquifers. The division into sectors according to hydrochemical fe atures, in addition to the inclusion as variables of both certain mino r ions and the ionic deviations of the theoretical mixing of freshwate r and seawater, have provided a clear characterization of the saliniza tion processes affecting the aquifer. The present study shows the appl ication of statistical methods to the characterization of the saliniza tion processes in the coastal aquifer of the Castellon Plain. The appl ication of these statistical methods (cluster analysis and principal c omponents analysis) has lead to the corroboration of the hypotheses de veloped from the previous hydrochemical study. Inclusion of specific v ariables (certain minor ions and ionic-Delta) into the PCA enhances a definition of the degree of the salinization processes.