We are proposing to address the following hypothesis: The nutrient load from rivers to Lake Michigan is disproportionally higher from episodic river flow plumes and therefore may exceed maximum allowable levels on an episodic level not captured by traditional synoptic monitoring and that quantifying the transport and fate of those nutrients in the nearshore region is important for developing management strategies to mitigate the impact of episodic events. We will make use of a nested sampling strategy to develop a new methodology that can be used to monitor nutrient inputs from episodic river inflows using water sampling and remote sensing imagery. The nested sampling strategy will employ continuous and event based sampling of nutrient fluxes and loads from two streams in northern Indiana, sampling of river inflow plumes using an autonomous underwater vehicle, synoptic samples collected from ships, and high-resolution satellite imagery of river plumes and coarser resolution imagery of the southern lake. Episodic data collection will be focused on mid-April through mid-June to capture spring high flow events coupled to farm nutrient application and planting. Base flow condition sampling will occur in August to capture low flow inputs into the lake and corresponding water quality information for the lake itself. This data will be used to complete the following research objectives:
- Objective 1: To quantify the transport of sediment and nutrients into Lake Michigan from rivers following heavy precipitation events, including the magnitude and frequency of significant nutrient loads into the lake and the relative distribution of loads between episodic inputs and those from baseline conditions.
- Objective 2: To quantify the transport and fate of nutrients within the episodic river plumes as they transition from the land surface (river channel) to the lake.