Submitted to: Water Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/1995
Publication Date: N/A
Interpretive Summary: Cooperative efforts among Hungarian and United States scientists have resulted in a strategy to estimate the potential for contamination of ground water by nitrate and herbicides in the midwest U.S. and Hungary. Shallow aquifers made of sand and gravel and bedrock aquifers are most likely to be contaminated and are being studied in an initial test of the strategy. The strategy includes the following steps: 1) Identifying characteristics of ground water needed to classify these resources; 2) Mapping the ground water classes using a regional geographic information system; and 3) Estimating the occurrence of agricultural chemicals by applying leaching models to representative conditions in each ground water class. In the U.S. project, soil data bases are being used to map ground water classes and model input. Estimates of potential contamination will be evaluated against data from a regional survey to shallow ground water recently completed in the Midwest. The Hungarian project is developing new maps of basic characteristics of geology and ground water that can be used to model potential contamination of the 1-meter root zone and deeper parts of the ground water system.
Technical Abstract: The potential for ground water contamination by agricultural chemicals exists in many regions of the world. A collaborative effort between Hungarian and United States scientists has developed a general strategy to estimate the regional vulnerability of ground water to agricultural chemicals. The midwest U.S. and most of Hungary are major agricultural regions with similar hydrogeologic settings. Many areas where ground water provides public drinking water supplies in these regions are vulnerable to ground water contamination. The vulnerability of shallow, unconsolidated aquifers and thinly-covered bedrock aquifers to agricultural chemicals is being investigated in an initial application of the strategy. This strategy integrates elements of overlay methods of vulnerability estimation, process-based modeling methods, and statistical methods. Strategy steps include: Identifying characteristics of ground water needed to classify regional ground water resources; mapping the spatial distribution of aquifer classes (unconsolidated and bedrock) using a regional geographic information system; and estimating the occurrence of agricultural contaminants by applying leaching models to representative conditions in each aquifer class. In the U.S. project, pedologic data bases are being used for both mapping aquifer classes and model input. Estimated vulnerability will be evaluated against data from a regional survey of shallow aquifers recently completed in the Midwest. The Hungarian project is developing new maps of basic hydrogeologic characteristics with data that can be used to model vulnerability of the 1-meter root zone, the unsaturated zone, and the saturated zone.