Other Sensitive Ground Water Areas in Nevada An Ongoing Study

摘要

In addition to ground-water protection areas, the Nevada Division of Environmental Protection (NDEP) needs to characterize other sensitive ground water areas (OWGWAs) in Nevada. OSGWAs are areas where protecting underground sources of drinking water is critical. To characterize OSGWAs, the U.S. Geological Survey, in cooperation with NDEP, is evaluating the susceptibility and vulnerability of ground water to anthropogenic contamination throughout the State. The objectives of this 4-year (2001-05) study are to (1) delineate regions of Nevada with similar hydrogeologic characteristics and (2) estimate the probability of detecting anthropogenic contaminants in ground water. Hydrogeologic regions will be delineated by cluster analysis of selected variables (e.g. Precipitation, soil permeability). These regions will form the basis of determining what existing data represents, extrapolating estimates to similar regions, and determining which regions are lacking data to guide new data-collection efforts. New data will include nitrate, the most commonly measured anthropogenic contaminant, and ground-water age dating. The probability of detecting anthropogenic contaminants is one index that can be used to evaluate aquifer susceptibility and vulnerability. Existing water-quality data and information on variables that could be related to water quality (e.g. Population density, land use, depth to ground water) are being compiled from many sources and input to a database and geographic information system. Equations will be developed by logistic regression between the water-quality data and variables correlated with the detection of anthropogenic contaminants. Currently (August 2002), the study is in the data compilation phase and starting to delineate hydrogeologic regions of Nevada.