GROUNDWATER VULNERABILITY ASSESSMENT - 2 CASE-STUDIES USING GIS METHODOLOGY

In the first case study presented here, a geographic information syste m (GIS) is used to create a groundwater vulnerability map of the Midla nds and northwest of England by overlaying regional information on the solid geology, Quaternary drift cover and soil cover. The map reveals that areas of extreme and high groundwater vulnerability occur in the vicinities of Birmingham, Liverpool and Manchester. In the second stu dy, a GIS is used to create a groundwater vulnerability map for southe ast England and to combine this information with results from a routin g model for the transport of hazardous aqueous waste within the region . The routing model utilizes an accident-minimizing scenario and expre sses the potential pollution threat to groundwater as the number of ta nker-kilometres directed over each groundwater vulnerability class. It is concluded that a GIS methodology is very suitable for groundwater vulnerability mapping, providing an ability to integrate multiple laye rs of information and to derive additional information, for example on pollution risks. A GIS also allows flexibility in the revision of map s should existing information become obsolete, or revision of the grou ndwater vulnerability classification scheme be necessary.