Sediment and Sediment-Assisted Nutrient Transfer in Small Agricultural Watersheds in Southwestern Ontario

Sediment and nutrient export was evaluated in a small agriculture-dominated watershed that drains into Rondeau Bay, Lake Erie. Understanding the dynamics between runoff, sediment entrainment, and nutrient transport is key to mitigating the detrimental impacts of agricultural practices on water resources. In this study the following hypothesis was tested: the quantity and quality of suspended sediment yields in agricultural settings controls nutrient transfer from runoff. Stream discharge and water quality was monitored at three locations along a tributary reach within the Rondeau Bay basin during the 2013 growing-harvest season. This research concludes that agricultural-based nutrient loading into Lake Erie is sediment-assisted and that this sediment potentially derives from in-channel and tile drain sources. Nutrients were potentially linked to the stream with tile drains allowing for direct Phosphorus and Nitrogen transfer. The findings have important implications for future soil loss and thus nutrient loading from agricultural settings, especially during extreme events.