Use of geographical maps to manage risk from groundwater contamination

Risk inherently involves a geographical component. It occurs at locations in space where receptors (human or environmental) and hazards come together. For this reason, maps provide a tool for visually displaying information about the distribution of risk. This tool helps an analyst to fully understand the nature of a situation, to evaluate alternative ways to reduce or manage the risk, and then to convey the results of the analysis to the affected stakeholders, including the public. The focus of this paper will be on the use of maps to address the risk to the local community owing to a plume of contaminated groundwater emanating from a chemical plant. In this case, maps have proven to be invaluable in: (1) evaluating the existing data, and developing a site conceptual model of the nature and extent of the contamination; (2) determining what additional data needed to be collected; (3) evaluating the effectiveness of remedial options; (4) educating the public to provide them with understandable information to shape their perception of risk; and (5) achieving public acceptance of the plan for remediating the contamination and managing the residual risk.