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BIO

Rebecca Diehl is a Research Assistant Professor in the Department of Geography and Geosciences at ¶¶Òõ̽̽. Trained as a fluvial geomorphologist, she is interested in understanding the functioning of river systems to support a more sustainable management of our water resources. Rebecca’s current research focuses on mapping, measuring and modeling the physical settings and processes that support the ecosystem services of rivers and floodplains, including their role in water quality mitigation, flood attenuation, and habitat provisioning. She works across scales, collecting field observations to build empirical datasets, and analyzing large geospatial datasets that inform the development of statistical or process-based tools. Previous research emphasized the importance of biotic factors (i.e., riparian vegetation, non-native species, wood jams) on fluvial processes and channel form.  

Rebecca received her PhD in Watershed Sciences at Utah State University and has a master’s in Geography at the University of North Carolina, Chapel Hill. Prior to joining the faculty at ¶¶Òõ̽̽ in 2018, she was an NSF Science, Engineering, and Education for Sustainability Fellow at the University of Montana leading an interdisciplinary team in the development of a hydrologically-driven model of riparian ecosystem dynamics in the Colorado River Basin. She remains engaged in questions around water resource management and environmental flow prescriptions in the Colorado River Basin.

Current Projects

Phosphorus Deposition and Retention on Floodplains and Wetlands. This project is building an understanding of the capacity of floodplains and riparian wetlands to mitigate the downstream movement of phosphorus. Since 2019, at more than 25 sites in the Lake Champlain Basin, Vermont, we have been collecting observations on the flood event-scale deposition of particulate phosphorus and on dissolved phosphorus dynamics on floodplains and riparian wetlands. The data supports the claim that floodplains and wetlands can capture large volumes of phosphorus from floodwaters, but that there is large variability because of river-floodplain hydrologic connectivity, geomorphic processes that influence the movement of water and sediment through a watershed and across a floodplain, and land use histories. We continue to monitor sites to build a robust dataset and to understand how floodplain functioning changes through time. Our findings are being integrated into watershed planning tools to prioritize natural resource projects that help meet clean water goals. Collaborators include Beverley Wemple (¶¶Òõ̽̽ Geography and Geosciences), Kristen Underwood (¶¶Òõ̽̽ Civil and Environmental Engineering), Eric Roy (¶¶Òõ̽̽ Rubenstein School), Adrian Wiegman (¶¶Òõ̽̽ RSENR), and Don Ross (¶¶Òõ̽̽ Plant and Soil Science). This work has received funding from the Lake Champlain Basin Program, The Nature Conservancy-Vermont, Lake Champlain SeaGrant, Vermont Department of Environmental Conservation, and USDA’s NRCS Conservation Effects Assessment Project.

Representation of Floodplains in the National Water Model. Floodplains can slow flood waters, reducing peaks, and building resilience in downstream communities. Yet, floodplains are not represented in the National Water Model, introducing uncertainties for flood routing algorithms, and therefore errors in flood inundation predictions. As part of the Cooperative Institute for Research to Operations in Hydrology (CIROH) at ¶¶Òõ̽̽, we are exploring approaches to characterize a floodplain’s topographic, landcover, and other characteristics that influence flood attenuation, in a scalable way to incorporate into the National Water Model. Collaborators include Kristen Underwood (¶¶Òõ̽̽ Civil and Environmental Engineering) and Beverley Wemple (¶¶Òõ̽̽ Geography and Geosciences).

Improved Representation of Habitat in Floodplain Planning Tools. We are building approaches to understand and map the quality of riparian habitats on floodplains in the Lake Champlain Basin. Development of models that link hydrogeomorphic (and other) characteristics, with the spatial distribution of natural communities, and the habitat function using indicator species, will be integrated into the Vermont’s Functioning Floodplain Initiative. This work is led by Elizabeth Doran (¶¶Òõ̽̽ Civil and Environmental Engineering) and collaborators include Kristen Underwood (¶¶Òõ̽̽ Civil and Environmental Engineering), Brittany Mosher (¶¶Òõ̽̽ Rubenstein), and James Murdoch (¶¶Òõ̽̽ Rubenstein). This project is funded by the Lake Champlain Basin Program with additional support from The Nature Conservancy-Vermont.

Flow Prescription for the Yampa River. The Yampa River is the last lightly regulated major of the Colorado River and supports a healthy ecosystem in Dinosaur National Monument. In collaboration with Jonathan Friedman of the USGS, I am developing a resource for the National Park Service and other stakeholders to evaluate the optimal volume and timing for flow extractions, based on their (minimized) impact to the natural resource. The approach is a novel take on a flow prescription and targets the preservation of not only target flows, but also the natural variability in flows critical for physical and ecological processes.

Publications