Increased sediment introduction and transport in streams negatively impact water quality. Deleterious effects include reservoir filling, water pollution and ecological impairment. Sediment introduction and transport typically takes place during storm events. Phosphorus introduction, generally from loss of agricultural runoff and soil erosion also typically takes place during storm events. When phosphorus is applied for agricultural uses it is preferentially retained by smaller sediments. During storm events, these phosphorus rich sediments are more likely to enter the stream system. A small number of large storms can account for a large percentage of sediment and total phosphorus introduction, leading to elevated levels in waterways. Increased phosphorus introduction into waterways is a main driver of algal blooms and hypoxic conditions such as the dead zone that forms in Lake Erie.The goal of this study is to determine if turbidity, total suspended sediments, and total phosphorus exhibit similar transport behaviors in an agricultural watershed. Three years of data are available at the Six Mile Creek watershed located in McLean County Illinois. Analysis of total suspended sediments, turbidity, and total phosphorus data show that both total suspended sediments and turbidity display a correlation ranging from weakly to strongly positive with total phosphorus. Hysteresis analysis was conducted to elucidate the similarities in transport mechanisms between total suspended sediments, turbidity, and total phosphorus. Concentration discharge relationships observed in the hysteresis patterns were further described by calculating flushing index and hysteresis index values for these events. Evaluation of the hysteresis patterns, flushing index, and hysteresis index allows for further breakdown on an annual, seasonal, or event-based scale. It was discovered that the hysteresis patterns displayed, the flushing index, and hysteresis index was behaving similarly for both turbidity and total phosphorus on a seasonal, annual, and event-based basis in the Six Mile Creek Watershed. Farmers and agricultural managers may be able to better develop sustainable land management practices if there is a consideration of the correlations between turbidity, total suspended sediments and total phosphorus and the timing of their introduction. This could ultimately mitigate the excessive amount of TSS, and TP introduced into surface waters
