Export of Carbon, Nutrients and Microbiological Indicators in Beaver Creek Watershed, Tennessee

Storms are the most important events impacting stream water quality at the watershed-scale. With the goal to develop effective water resource management strategies for the impaired Beaver Creek Watershed in East Tennessee, the impacts of storm events on water quality were assessed by monitoring the intra-storm dynamics of the export of carbon, nutrients, and microbiological indicators (E. coli), which are parameters critical to water quality and ecological functions of the target watershed. The dynamics of carbon export from the Beaver Creek Watershed as represented by dissolved organic carbon revealed distinct carbon transport mechanisms as a function of storm intensity, with organic carbon input dominated by overland runoff during the largest storms while organic carbon transported with groundwater was shown as a more important source during smaller storms. Further characterization of the dissolved organic matter in different storms confirmed that humic substances derived from terrestrial organic materials may be the main source of carbon export during high storm flows. Nutrient export was also linked to carbon transport as phosphorus transport was associated with terrestrial sources and overland runoff. However, the lack of correlation between the transport of nitrate and storm flow suggests that the main sources of nitrate was likely groundwater, which was not impacted by storm events in the short term. Storm events also impacted the export of the microbiological indicator E. coli, which could be attributed to two sources related to sediment transport: overland runoff and sediment resuspension.