Assessing Regional Ground Water Contamination Potential

David R. Soller, Richard C. Berg, Richard L. Bernknopf

Assessing the potential for ground water contamination is a complex process, especially for large regions. For local areas, detailed deterministic models of ground water flow and fate of contaminants can be developed by integrating physical process concepts with closely spaced, detailed data to fit an equation to the data at hand. However, such models have limited utility for larger regions, largely because of sparseness of data. Therefore, for regional assessments, qualitative maps of vulnerability are more appropriate. For example, a set of conceptual rules can be applied to regional data to produce a map showing areas of relative contamination potential. Using that approach, we have produced a regional vulnerability map for part of the southern Great Lakes area, based n three-dimensional sequences of geologic units and their potential for transmitting water and contaminants.

Such maps allows decision makers to assess broad areas of relative vulnerability. However, because qualitative regional maps do not predict where contamination is actually occurring, nor the rate of contamination, we are developing a stochastic method to forecast that information. The method uses hydrologic, earth science, and socioeconomic data in regression analyses and Markov chain processes. We are developing this forecasting tool for a large region where subsurface information is sparse. With improved information, such as may be acquired for smaller areas, the model can become more accurate.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995