Our research investigates how water moves through landscapes and influences geologic hazards. We combine field investigations, numerical modeling, and remote sensing to explore the physical interactions between groundwater, landslides, rivers, sediment, and floods.
RESEARCH AREAS:
Feedbacks between landsliding and river erosion
River valleys often have hazards associated with landslides because river erosion can create steep slopes prone to failure and landslides can dam rivers and cause flooding. However, the role of rivers in causing landsliding is not well understood: are there patterns in space and time leading up to landslides next to rivers? Does the river shape respond to landsliding? What dimension of river erosion is most responsible for destabilizing hillslopes and triggering landslides? Our work investigates these questions in western Washington State as well as other regions to help understand spatial patterns of landslides in river valleys and illuminate new way valleys may widen over time under coupled river-landslide interactions.
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Field monitoring of landslide reactivation in glacial terraces
Washington glacial terraces bounding river valleys can produce large and highly mobile landslides. In collaboration with the USGS, we monitor landslide displacement and pore pressures at an actively eroding glacial terrace adjacent to the Nooksack River, WA. This research is aimed at understanding surface & subsurface hydrologic mechanisms related to landslide timing.
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Groundwater & slope-stability modeling
Groundwater plays a critical role in slope stability, as changes in subsurface flow and pore-water pressure can influence the timing and location of landslides. Our research seeks to understand how groundwater flow responds to subsurface geology, topography, and hydrologic forcing, and how these responses influence slope stability. We are particularly interested in integrating numerical groundwater flow models with slope stability analyses to investigate the hydrologic conditions leading to landslide initiation.
We also develop computational tools and interactive Python tutorials for groundwater modeling, including steady-state and transient simulations using MODFLOW and FloPy.
FloPy notebooks:
Landslide dam stability & failure mechanisms
Landslides can block river valleys, forming temporary dams that may fail suddenly and generate destructive outburst floods. Our research investigates the physical processes governing landslide dam stability and failure, including seepage, internal erosion, overtopping, and breach development. We combine field investigations, remote sensing, and numerical modeling to understand how dam geometry, sediment properties, and hydrologic conditions influence failure mechanisms and the dynamics of resulting outburst floods.
Flash floods & granular flows
Flash floods can rapidly mobilize and transport sediment, producing flows that range from turbulent, water-dominated floods to dense granular debris flows. Our research investigates the physical processes governing these flows, with particular interest in how interactions between water and sediment influence flow dynamics and hazard potential. We use numerical modeling, including D-Claw, to simulate postfire flash flooding and explore the mechanisms governing transitions between fluid- and grain-dominated flow regimes.
Feedbacks between sediment transport & flooding
Floods mobilize and redistribute sediment, but the resulting changes in riverbed elevation can also influence where and when rivers flood. Our research investigates the physical feedbacks between sediment transport, channel conveyance, and flood hydraulics, with particular emphasis on how erosion and deposition alter flow patterns and flood hazards. We combine field observations, bathymetric data, and numerical modeling to understand how these coupled processes evolve during and between flood events.
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