Type of soil media map expressed as an index value according to DRASTIC ranges from 1 to 10. The lowest values in the area (index value of 4) - correspond to loam and silty loam soils and the highest values (index value of 10) correspond to gravel soils or terrains with non-existent soil.

Depth to groundwater level distribution map expressed as an index value according to DRASTIC ranges from 1 to 10, being 10 the most shallow groundwater level (less than 1.5 m) and 1 the most deepest (more than 50 m).

Concentration of flow factor map indicates the reduction of protection of the groundwater surface due to karst development. It is expressed as a value according to COP index ranges from 0 to 1, being the range of lowest values (0 - 0.2) the one that indicates a very high reduction of the overlying layers protection (factor O), and the range of the highest values (0.8 – 1) a very low reduction of the overlying layers protection.

Overlying layers factor map indicates the natural protection of the groundwater surface provided by the geological layers of the unsaturated zone and the overlying soil. It is expressed as a value according to COP ranges from 1 to 15, being 0 the less degree of protection and the range of 8 - 15 the highest degree of protection.

Vulnerability assessment output map using COP method

Precipitation factor map indicates the reduction of groundwater surface protection due to climatic settings. It is expressed as a value according to COP ranges from 0.4 to 1, being the range 0.4-0.5 the highest degree of protection reduction and the range of 0.9-1 the lowest degree of protection reduction.

Slope distribution map expressed as an index value according to DRASTIC ranges from 1 to 10, being 10 the areas with lowest slopes (less than 2 %) and 1 the areas with highest ones (more than 18%).

Net recharge map expressed as an index value according to DRASTIC ranges from 1 to 10, being 10 the net recharge greater than 500 mm and 1 the recharge less than 50mm.

Hydraulic conductivity map expressed as an index value, according to DRASTIC ranges from 1 to 10, being 10 the high permeability aquifers (> 1.0*10-2 m/s) and 1 the low permeability aquifers (< 5.0*10-7 m/s).

Vulnerability assessment output map using DRASTIC method (Aller et al., 1987)