PATTERNS IN STREAM SEDIMENT TRANSPORT DYNAMICS IN AN AGRICULTURAL LANDSCAPE

Storm events are the driving force behind the transport of sediment in streams, but land use characteristics are also able to influence erosion and the input of sediment into streams. It is important to understand the sources for the sediment transported in streams, whether it be internal or external, and the transport dynamics of the sediment.

In this project we are examining the patterns of sediment transport in streams, by examining hysteresis, as well as the peak shape, during storm events. Within the peak shape we are examining if it is a single or double peak, and if it is a double what is the relative size. This will allow us to better understand sediment movement into and through the streams.

For this project we collected data from Six Mile Creek, located half a mile west of Hudson, Illinois. This creek drains a 106km-squared agricultural watershed. The turbidity and depth data were collected using a DTS-12 sensor set to 15 minute intervals over a three year span from 2016 to 2019.

So far results have shown that some stream events have a single turbidity peak after a storm event, while others have a double peak. The smaller peak often occurs after the larger peak in the double peak but occasionally does appear before. These double peaks could be related to the input by tile drains. For hysteresis the results so far have shown that a clockwise pattern has been common in the summer while a counter clockwise pattern has been more common in the fall. This change of pattern indicates that sediment is being sourced from different places at different times of year.

Our research so far indicates that sediment transport dynamics are variable throughout the year, typically changing with the seasons.