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Fig. 5.3 Box and whisker plots of discriminating parameters (parameter values in Y-axis are Z
scale transformed values.); Fluoride a EC b Nitrate c Magnesium d Arsenic e and Cadmium f
Consequently, these variables cause variations in the groundwater quality. According
to spatial cluster analysis, 298 sampled wells were grouped into cluster, 1 and those
wells had high mineral concentrations compared to cluster 2. Wells grouped in cluster
1 (except two sampling wells) were located in intermediate (intermediate zone is the
area sandwiched between the wet and dry zones receiving a mean annual rainfall of
1750–2500 mm.) and dry zone of Sri Lanka, while 964 wells located in all three climatic zones were clustered under cluster 2. Shallow karstic aquifer, shallow aquifers
on coastal sands, deep confined aquifer, alluvium aquifer and regolith aquifer of hard
metamorphic rock region are the main types of aquifers located in intermediate and
dry climatic zones (Panabokke 2007). Shallow karstic aquifer is limited to the western