2026 CSDMS meeting-055
From CSDMS
(if you haven't already)
Log in (or create account for non-CSDMS members)
Forgot username? Search or email:CSDMSweb@colorado.edu
Browse abstracts
Simulating the impact of glacial isostatic adjustment on Potomac River erosion patterns near Great Falls (Virginia) using hydrodynamic models
Aidan Lewandowski,
(she/her/hers),University of California, Santa Cruz Santa Cruz California, United States. aillewan@ucsc.edu
Tamara Pico, University of California, Santa Cruz Santa Cruz California, United States. tpico@ucsc.edu
Sean Gallen, Colorado State University Fort Collins Colorado, United States.
Paul Bierman, University of Vermont Burlington Vermont, United States.
The Potomac River presents a unique setting for examining how regional forcings, such as glacial isostatic adjustment (GIA), influence fluvial incision. Although the river remained unglaciated during the Pleistocene, it lies along the peripheral bulge of the Laurentide Ice Sheet. Uplift and subsidence of the ice sheet’s peripheral bulge impacts channel slope, which can perturb a river’s ability to erode or transport sediment. Previous predictions show that GIA increased channel slope along the Potomac River by > 5x leading into the Last Glacial Maximum, from ~35 to 20 ka, near Great Falls, Virginia (Pico et al., 2019; Bierman et al., in prep). This slope steepening corresponds to the timing of local strath terrace formation during a pulse of rapid incision documented by 10Be dating (Reusser & Bierman, 2004). We aim to explore whether GIA-induced tilting can produce the observed increase in river incision. We will perform hydrodynamic simulations on reconstructed topography corrected for GIA using a range of probable discharge values. We will predict how GIA-induced slope impacts simulated water velocities and thereby shear stress patterns. We will then compare our simulated shear stress values to the threshold required for plucking, permitting us to predict how slope change governs where erosion might occur. Our overarching goal is to understand how space-varying perturbations to channel slope impact erosion patterns.
