Lesley Perg is part of a multi-year project to develop an integrated sediment budget for the Le Sueur River basin in southern Minnesota. The Le Sueur contributes a significant amount of sediment and nutrients to the Minnesota River and Lake Pepin. Significant stretches of the Le Sueur and Minnesota rivers, as well as Lake Pepin, are impaired by turbidity and (under the Clean Water Act) a plan for addressing this is required.
Lesley and her postdoc, Patrick Belmont, use cosmogenic nuclides (Beryllium-10 and Aluminum-26) to constrain landscape erosion rates over the past 10,000+ years and trace sediment storage and transport throughout the Le Sueur basin. The Le Sueur research team will use their understanding of long-term sediment dynamics, derived from cosmogenic nuclide analysis and field mapping, to compare long-term trends with modern sediment transport and erosion rates from stream water samples, aerial photography and LIDAR technology. Understanding sediment sources, sinks and fluxes during recent times as well as pre-human settlement is critical to the Minnesota Pollution Control Agency's development of a comprehensive watershed management plan that will increase the economic value of the Le Sueur River.
