Methodology for mapping GDEs
This methodology was applied separately to eight GIS analysis regions (called work packages). Each work package represented an area of broadly similar hydrogeological, ecological and climatic characteristics. It was assumed the interaction between groundwater and ecosystems was controlled by similar processes, and could be modelled by the same broad analysis rules within each work package.
The literature review enabled a conceptual understanding of the interaction between groundwater and ecosystems to be developed. From this, a set of rules describing the potential for groundwater/ecosystem interaction was developed for each work package.
In the data selection step, existing spatial datasets were compared against the rules to determine where analysis could be undertaken. The ability to implement the rules developed in the literature review was dependent on the availability of relevant spatial data.
Once the datasets available to implement the rules had been confirmed, GIS analysis combined the rules and data to provide an interim product that showed the outcomes of each rule for each ecosystem. The outcomes of each rule were then rated to indicate the potential for groundwater/ecosystem interaction to be occurring. The term 'GDE potential' has been used to indicate the potential for interaction between groundwater and ecosystems.