Developing a sediment budget for the Root River, southeastern Minnesota.

Excessive sedimentation in streams and rivers is one of the top water quality concerns in the U.S. and globally. While sediment is a natural constituent of stream ecosystems, excessive amounts cause high levels of turbidity which can reduce primary and secondary production, reduce nutrient retention, and have negative impacts on fish reproduction and physiology. According to the United States Geological Survey (USGS), the small sediment particles can also provide attachment places for other pollutants like metals and bacteria. Key questions remain regarding the origin of excessive sediment observed in the Root River watershed, as well as the transport pathways of sediment through the landscape and channel network. To answer these questions, I will develop a sediment budget for the Root River, a 4,500 km2 watershed in southeastern Minnesota. Like other sorts of budgets, sediment budgets are a means of accounting for inputs, outputs, and changes in storage reservoirs within the system. Because watershed sediment fluxes are determined as the sum of many small changes (erosion and deposition) across a vast area, multiple techniques are required to adequately constrain all parts of the sediment budget. Specifically, this budget utilize multiple, redundant lines of evidence including sediment fingerprinting data, remote sensing analyses, watershed modeling, and direct measurements of water flow and sediment loads through continuous monitoring by a number of Minnesota agencies. These overlapping methods will provide a strong constraint for the budget and improve its reliability. After completion, the sediment budget will offer a better understanding of excessive sediment dynamics causing reach impairment in the Root River, which will be used in the development of watershed scale restoration planning