2000 GSA Annual Meeting -- Reno, Nevada
2000 GSA Annual Meeting -- Reno, Nevada
Author(s): MURRAY, Kyle E., Department of Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401, kmurray@mines.edu; SCHLOSSER, Stephanie A., Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401; MCCRAY, John E., Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401; and AUSTIN, Brad, Colorado Department of Public Health and Environment, 4300 Cherry Creek Dr. South, Denver, CO 80246
Keywords: GIS, groundwater, vulnerability, pesticide, contamination
Ground water resources underlying irrigated agricultural areas in the state of Colorado may be vulnerable to pesticide contamination. Contamination of these ground water resources could be prevented by development of accurate vulnerability models and appropriate recommendations for decreasing the potential impact of pesticide use. This study represents a portion of ongoing research, utilizing readily available data, to develop such a vulnerability model. More specifically, the purpose of this study is to test a vulnerability index equation, using cell-based Geographic Information System (GIS) analysis, that was developed based on previous results reported in the literature and attributes of available spatial data. The vulnerability index equation incorporates soil characteristics, hydrogeologic factors, chemical characteristics, and irrigation use factors including: bulk density, organic matter, available water capacity, hydraulic conductivity, depth to ground water, pesticide decay rate, pesticide organic carbon partition coefficient, and extent of irrigation. The vulnerability index equation is calibrated to a subset of ground water analytical results. A matrix of vulnerability indices is then produced for several agricultural pesticides commonly used in portions of Colorado. The spatial distribution of ground water vulnerability is then verified by measuring the spatial correlation of the vulnerability indices versus the detections of pesticides in ground water. Spatial representations of these results are produced to assist agriculturists in planning and regulating pesticide use in the state.
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