3. Results and discussion3.1. Vulnerability assessment The original vulnerability map of the study area (Fig. 7A) clearlyshows the dominance of “high” and “moderate” vulnerability classes in the southeast and northwest parts, respectively. Table 6presents the Pearson’s correlation coefficients applied to define the correlation between the nitrate measurement and the DRASTIC val-ues, which were calculated at 0.37. This value is relatively low,indicating that the original vulnerability index must be changedto obtain a realistic assessment of the potential contamination inthe study area. Thereafter, the DRASTIC model was modified. Fig. 8Apresents the vulnerability indices and corresponding area percent-ages. The percentage for the “very high” and “high” classes was at50.09%, whereas only less than one-fifth of the total area was cov-ered by “low” and “very low” classes of vulnerability to pollution.In AHP–DRASTIC, the vulnerability indices were derived from AHP