GIS-BASED GROUNDWATER POLLUTION HAZARD ASSESSMENT - A CRITICAL-REVIEW OF THE DRASTIC MODEL

The protection of groundwater quality is an important issue confronting much of the world's populace. Geographic information systems (GIS) have been shown to be useful tools for assessing groundwater pollution hazard. Efforts to use GIS in implementation of the DRASTIC groundwater vulnerability model and its derivatives are reviewed. Problems related to data quality, model formulation, and model validation are discussed, and suggestions for augmentation and enhancement of the model are offered. It is recommended that additional research be focused upon (1) determination of the relative importance of, and possible interdependencies among, parameters considered in the model; (2) incorporation of other factors (e.g., land use) in the model, and linkage of DRASTIC with complementary models (e.g., capture zone models); (3) investigation of scaling issues; (4) expansion of DRASTIC through GIS-based 3D, finite-element, solute transport, and temporal modeling; (5) use of expert systems; (6) validation and verification of model performance; and (7) means to assist decision-makers in using model results.