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

The protection of groundwater quality is an important issue confrontin g much of the world's populace. Geographic information systems (GIS) h ave been shown to be useful tools for assessing groundwater pollution hazard. Efforts to use GIS in implementation of the DRASTIC groundwate r vulnerability model and its derivatives are reviewed. Problems relat ed to data quality, model formulation, and model validation are discus sed, 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 interdepe ndencies 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) investigat ion of scaling issues; (4) expansion of DRASTIC through GIS-based 3D, finite-element, solute transport, and temporal modeling; (5) use of ex pert systems; (6) validation and verification of model performance; an d (7) means to assist decision-makers in using model results.