Groundwater Vulnerability

The map below shows a groundwater vulnerability to contamination dateset produced using the DRASTIC method (which considers depth to groundwater, recharge, aquifer media, soil type, topography, impact of the vadose zone, and conductivity). This dataset can be used to give a broad indication of relative vulnerability to non-point source pollution*. 

*Please note the GRA2 project was completed as part of a national planning requirement and the data must be used with this in mind. The quantification and mapping of groundwater is an inherently uncertain and low confidence task – thus an exact answer is never achievable. The data is not to be used for site specific information. The useful scale of the data is to the quaternary catchment level and should not be used in a more detailed scale than this. The GRA2 was a “best estimate” at the time of the project in 1995. The intention of the project was to develop a methodology and to release data sets thereby enabling continual improvement of the accuracy of the methodology and the data sets. The data is to be used bearing the above in mind.

Source: Department of Water and Sanitation. Groundwater Vulnerability [raster geospatial dataset] 2005. Available from the SASDI website.