Effects of Development on the Big Darby Creek Watershed: Stream Geochemisty
This study focuses on the chemical changes in the water of the Big Darby Creek and its tributary, the Little Darby Creek. As anthropogenic disturbances increase in the watershed they may affect the stream geochemistry.
For this study water samples are collected biweekly from the Little Darby Creek in West Jefferson and from the Big Darby Creek in Darbydale to assess seasonal variability. The samples are analyzed for major ions. Our preliminary results show a decreasing trend in nitrate concentrations in both locations from spring into the fall and an increase from fall to winter. We suggest that this is related to the seasonal application of fertilizer and the decomposition of organic matter in the late fall season. Chloride concentrations show contrasting trends between the two locations. In the Little Darby Creek chloride remained relatively constant until the winter where an increase is seen, but in the Big Darby Creek the concentration of chloride increased into the fall. This higher chloride concentration may be related to the continual leaching of winter-applied road salt from major highways draining into the Creek. Results of this study will be discussed in terms of land use in the Big Darby watershed. The data from this study will be compared to historical data collected by the USGS to understand long-term changes in water quality.