Modeling the Risk of Groundwater Contamination Using DRASTIC and Geographic Information Systems in Houston County, Minnesota

Groundwater plays an important role in the environment as it contributes to irrigation, streams and rivers, and wetland habitats affecting many species of plants and animals. Groundwater provides over half the drinking water for the nation; it is important to protect such an important resource. Groundwater contamination, though almost impossible to stop in some areas, can be minimized by delineating vulnerable areas. The use of modeling with Geographic Information Systems (GIS) contributes significantly to the delineation of vulnerable areas. The DRASTIC model, introduced by the U.S. Environmental Protection Agency (EPA), studied several key hydrogeologic characteristics that affect groundwater infiltration. DRASTIC is an acronym standing for Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and hydraulic Conductivity. Well test results have shown that areas of Houston County, Minnesota may be contaminated and that further research is needed. Data was collected, processed, and presented in GIS to spatially represent the DRASTIC parameters. Models were produced to show the susceptibility to contamination of groundwater in Houston County. Maps indicate areas of high risk to be further researched to resolve issues of groundwater contamination.