Material supply

Why study material supply?

River landscapes are formed to transport the material — sediment, water, wood, etc. — supplied to them. Supply of this material is a function of several interacting variables, including climate, vegetation, topography, geology, and human activity. If we can better understand the web of processes that produce and supply material to the river landscape, we can better anticipate how future changes (in climate, in urbanization, in management, etc.) might alter that supply and, in turn, drive the evolution of the river landscape. With this enhanced knowledge, we can be better equipped to manage river systems for our changing world.

— Projects —

Impacts of sediment supply increases on river landscapes

Take-home points: Tributary erosion can drive enhanced channel change and elevated forest establishment in large river basins.

More generally the scale of channel response to an increase in sediment supply (i.e., a change in grain-size vs. a change in planform) is dependent on whether thresholds of influx grain size and volume relative to antecedent channel conditions are crossed

Publications

Kemper, Thaxton, Rathburn, Friedman, Mueller, Scott, 2022, ESPL (link)

Kemper, Rathburn, Friedman, Mueller, Wohl, & Scamardo, 2023, Earth-Science Reviews (link)

Large wood in burned watersheds

— this work is ongoing —

Using field surveys and machine learning, we seek to understand how fire influences the supply of large wood to streams in burned watersheds, how that wood influences sediment dynamics following fire, and what variables influence these patterns (topography, burn severity, etc.)

Collaborators

Patrick Belmont, Utah State University;

Scott David, Utah State University;

Brendan Murphy, Simon Fraser University

Nutrient supply in urban watersheds

Take-home point: Interactions between runoff, groundwater, and the built environment result in groundwater contaminant zones that are a steady source of various contaminants to urban streams

Publications

Welty, Moore, Bain, Talebpour, Kemper, Groffman, Duncan, 2023, Water. Resour. Res. (link)

Ducan, Welty, Kemper, Groffman, Band, 2017, Water Resour. Res. (link)

Snow avalanches & large wood supply in mountain watersheds

Take-home point: Avalanches deliver orders-of-magnitude greater wood to stream channels than background recruitment processes or similar mass movement events, suggesting they are a major (and perhaps overlooked) player in the natural wood regime of mountain streams

Publications

Kemper & Scamardo, 2023. Geophys. Res. Letters (link)

Forecasting sediment & nutrient loading with large-scale physical models & machine learning

— this work is ongoing —

Using ML models built on water quality monitoring data (high-frequency & discrete) in conjunction with hydrological forecasts from the National Water Model, we are looking to predict nutrient & turbidity loading with 1-7 days lead time

Publications

Kemper, Underwood, Hamshaw, Davis, Siemion, Shanley, & Scroth, 2025. JAWRA (link)

Kemper, Underwood, Hamshaw, Shanley, Isles, & Schroth. in review

Collaborators

Cooperative Institute for Research to Operations in Hydrology (CIROH);

Vermont Department of Environmental Conservation;

NYC Departmental of Environmental Protection;

USGS

Multi-scalar patterns & drivers of nutrient export

— this work is ongoing —

Using high-frequency sensors, traditional sampling data, and machine learning techniques, we are seeking to understand what drives patterns of nutrient, chloride, and sediment concentration at the watershed, regional, and continental scales

Collaborators

Andrew Schroth, University of Vermont;

Kristin Underwood, University of Vermont;

Patrick Clemins, University of Vermont;

Scott Hamshaw, US Geological Survey;

James Shanley, US Geological Survey

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