INVESTIGATION OF SPATIAL AND TEMPORAL VARIATIONS IN WATER QUALITY AROUND NORA, IL

The geologic landscape around Nora, Illinois is composed of Galena Limestone, overlaid by thin Quaternary deposits. The weathering of the Galena Limestone has created a terrain with karst and mantled epikarst. A high degree of connectivity between the surface water and the groundwater as a result of the karst causes the groundwater to be very susceptible to contamination. Construction of a large dairy operation, 6,850 head of cattle, was initiated southwest of Nora late in 2008. Owing to the potential for contamination of surface water, groundwater, and private wells, surface water and groundwater were monitored for a year to assess the spatial and temporal variability of the waters. These data will establish baseline chemistry data for comparison to future data in monitoring for potential changes in water quality. Six streams and six springs, in close proximity to the dairy operation, were sampled monthly for this study. Baseline water chemistry was established through monitoring the concentrations of major anions and cations, pH, temperature, specific conductance, carbon dioxide, alkalinity, hardness, and dissolved oxygen. Nitrate-nitrogen values ranged from 2.90 to 14.55 ppm for stream locations and from 0 to 30.10 ppm for spring locations. Except for temperature and sulfate, the water quality of streams and springs were statistically different from each other. As a whole, the streams experienced less spatial variation than the springs. Statistically different concentrations of chloride, nitrate-nitrogen, and sulfate were observed among both the streams and the springs. Almost all of the alkalinity and calcite levels for the streams were statistically similar spatially. Conversely, alkalinity and calcite values at the spring locations were statistically different spatially. Temporal analyses were only conducted on the stream data and one spring location; with the exception of temperature, none of the locations exhibited statistically different temporal variation among the chemical parameters. The data indicates that the water quality characteristics exhibited spatial variations, but temporal variations in water quality characteristics were not observed, which indicates that the surface water and groundwater are susceptible to local influences.