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Presented at the NABS Annual meeting, Anchorage, Alaska, 2006
in Watershed Science in Surface Drinking Water Supplies 2
Effects of septic systems and domestic water softeners on surface and shallow subsurface sater quality, Croton Watershed, New York
J.M. Hassett1, M.J. Mitchell2, D.I. Siegel3, and M Adam3.1Faculty of Environmental Resources and Forest Engineering, 312 Bray Hall, State University of New York College of Environmental Science and Forestry,, 2Faculty of Environmental and Forest Biology, 210 Illick Hall, State University of New York College of Environmental Science and Forestry, Syracuse, Ne, 3Department of Earth Sciences, Heroy Laboratory, Syracuse University, Syracuse, NY 13244
A one-year study of three small (50 to 70 ha) watersheds in the Croton River, NY watershed was conducted. The watersheds differed in residential density (0, 1.6, 2.8 houses ha-1); each residence had an on-site septic system. Each watershed was equipped with a meteorological station and weir. Samples were taken bi-weekly and during runoff events and from instrument clusters with throughfall collectors, lysimeters and wells. Clusters were characterized by Topographic Index(TI) and residential density upgradient of their location.
Significant differences in concentrations of Na+ , Cl-, Ca 2+, Mg 2+, and NO3- were observed, with highest concentration in high-TI, high residential density. Chloride (3.8 ± 2.7 vs 0.27 ± 0.34 mM), Ca2+ (1.5 ± 0.23 vs 0.23 ± 0.18 mM) and NO3- (1.5 ± 0.43 vs 0.07 ± 0.04 mM) all showed significant differences from monitoring wells in high-TI sites with high and zero residential housing density. High concentrations in baseflow, and seasonal ion concentration-discharge patterns during runoff events suggested the importance on septic systems and domestic water softeners on the ion budgets of the developed watersheds.
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