4.1. Cluster analysis
Cluster analysis groups a system of variables into clusters on the basis of similarities (or dissimilarities) such that each cluster represents a specific process in the system. In this study, the hierarchical cluster analysis (HCA) was applied to the raw data for each of the three different locations, using SYSTAT 11 (Systat Software Incorporated, 2004). HCA is a powerful tool for analyzing water chemistry data, and formulating geochemical models (Meng and Maynard, 2001). Several similarity/dissimilarity measures are available from the SYSTAT 11 package. A classification scheme using the Euclidean distance for similarity measures and the Ward's method for linkage produces the most distinctive classification where each member within a group is more similar to its fellow members than to any member outside of the group (Güler et al., 2002).