Correlation Between DRASTIC Vulnerabilities and Incidents of VOC Contamination of Municipal Wells in Nebraska

Because it considers basic hydrogeologic variables believed to influence contaminant transport from surface sources to ground water, the DRASTIC method can be a valuable tool for identifying ground‐water supplies that are vulnerable to contamination. Theoretically, areas with high DRASTIC scores should have more frequent occurrences of ground‐water contamination events than areas with low scores given similar land use, well construction, and well densities. Relationships between DRASTIC scores and incidents of contamination, however, have not been extensively documented. In Nebraska, significant positive correlation appears to exist between incidents of VOC contamination of ground‐water supplied community water systems and the relative hydrogeologic vulnerability of surficial aquifers as quantified with the DRASTIC method. These results provide a means of verifying the usefulness of planning tools such as DRASTIC for identifying areas where water supplies are most vulnerable to contamination from surface sources.