199-2 Fluvial Geomorphology Through the Lens of Surface Curvature Invariants

Session: Advances in Fluvial Processes and Sediment Transport, Part II

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Studies that connect models of erosion to spatial variation in landform geometry have helped shape our modern understanding of landscape evolution.  In fluvial landscapes, this means leveraging some combination of curvature, slope, and drainage area, which arise from mechanistic models of erosion, although process superpositions and feedbacks are often not considered in detail.  In practice topographic geometry is calculated almost exclusively from digital elevation data, however most workflows derive metrics of interest from map-view projections of the data. This introduces systematic projection error to their results, and misses an opportunity to leverage quantitative aspects of the intrinsic surface geometry. We build on the seminal work of Karl Frederick Gauss to show how a formal surface theory approach to DEM processing applied to fluvial topography in the Oregon Coast Range, USA quantifies this error, and permits the extraction of additional information from topography that reveals surprising, systematic structures in channel and ridge networks. By evaluating the distribution of curvature invariants we then sort the landscape into four distinct shape classes in both map-view and binned area-space, demonstrating how this approach provides a self-consistent means of both quantifying process regimes and classifying land surface geometry in near steady-state fluvial landscapes.   

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7400

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