Research

Advances in technology have provided an opportunity to better quantify how rivers transport water and sediment. This work seeks to better understand the coupling between river hydraulics and sediment transport through direct measurements of these processes in the field.

Lidar data allow us to quantify floodplain topography at meter scales. In combination with 2-D hydraulic/sediment transport models and field measurements, we can  understand the processes forming and maintaining topographic relief on floodplains and how that influences river-floodplain connectivity, because understanding such connectivity could help effectively restore floodplains.

How does branching river-network structure, underlying characteristics of the basin, and process dynamics organize water, sediment, and nutrients transported through watersheds? How do these factors lead to the emergence of "hotspots" where sediment accumulates or nutrient concentrations are highest? Furthermore, how can we use this information to inform river basin management?

Aquatic nitrate removal depends on interactions throughout an interconnected network of lakes, wetlands, and river channels. This work aims to assess where and how to restore wetlands for reducing nitrate concentrations and loads from agricultural watersheds. Floodplains may be effective at removing nitrate from agricultural watersheds and thereby alleviate downstream hypoxia. How should floodplain topography be configured (as part of a floodplain restoration) to most effectively remove nitrate?

What is the interplay between physical and ecological processes in shaping river corridors and maintaining river ecosystem functioning? Specific interests include how vegetation influences river channel geometry and floodplain topographic relief, and how flow and sediment affect fish, freshwater mussels, and macroinvertebrates.

Plastic pollution – specifically microplastics (MPs), which are <5mm sized plastic particles – is now ubiquitous in oceans and rivers. A combination of physical, chemical, and radiative (UV light) processes degrade large plastic materials into small fragments and leach chemical by-products. Once small, MPs become highly mobile, can adsorb other pollutants (such as DDT, PCBs, dioxins), and can be ingested by biota where MPs can have direct effects on an organism or bioaccumulate. The goal is to predict the occurrence, transport, breakdown, and fate of plastic pollution by size and composition in rivers, and ultimately to provide insight into potential management strategies to reduce the detrimental impacts of plastic pollution.