How well can hillslope evolution models "explain" topography? Simulating soil transport and production with high-resolution topographic data

Research Article| September 01, 2008 How well can hillslope evolution models "explain" topography? Simulating soil transport and production with high-resolution topographic data Joshua J. Roering Joshua J. Roering 1Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403-1272, USA †E-mail: jroering@uoregon.edu Search for other works by this author on: GSW Google Scholar Author and Article Information Joshua J. Roering 1Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403-1272, USA †E-mail: jroering@uoregon.edu Publisher: Geological Society of America Received: 30 Jun 2007 Revision Received: 28 Dec 2007 Accepted: 03 Jan 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2008 Geological Society of America GSA Bulletin (2008) 120 (9-10): 1248–1262. https://doi.org/10.1130/B26283.1 Article history Received: 30 Jun 2007 Revision Received: 28 Dec 2007 Accepted: 03 Jan 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Joshua J. Roering; How well can hillslope evolution models "explain" topography? Simulating soil transport and production with high-resolution topographic data. GSA Bulletin 2008;; 120 (9-10): 1248–1262. doi: https://doi.org/10.1130/B26283.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The morphology of hillslopes is a direct reflection of tectonic forcing and climatic and biologic processes that drive soil production, mobilization, and transport. Soil transport on hillslopes affects river incision by providing tools for channel abrasion and controls the distribution of sediment that influences aquatic habitat. Although numerous hillslope transport relationships have been proposed over the past 60+ years, a comprehensive analysis of model predictions for a real landscape has not been performed. Here, we use high-resolution topographic data obtained via airborne laser swath mapping (ALSM) to simulate the long-term evolution of Oregon Coast Range hillslopes and test three published transport models and a new model that accounts for nonlinear depth- and slope-dependent transport. Analysis of one-dimensional, steady-state solutions for these four models suggests that plots of gradient-curvature may be diagnostic for distinguishing model predictions. To evaluate two-dimensional model predictions for our field site, we assumed local steady-state erosion for a 72,000 m2 sequence of hillslopes and valleys. After calibrating each of the four models, we imposed constant base-level lowering for cells within the valley network, simulated 500,000 yr of soil production and transport, and determined which transport model best preserved morphologic patterns that describe the current landscape form. Models for which flux varies proportionally with hillslope gradient generated broadly convex hilltops inconsistent with the sharp-crested, steep-sided slopes of our study site, whereas the two nonlinear slope-dependent models produced convex-planar slopes consistent with current hillslope form. Our proposed nonlinear slope- and depth-dependent model accounts for how soil thickness controls the magnitude of biogenic disturbances that drive transport; this model best preserved the current landscape form, particularly the narrow, sharply convex hilltops characteristic of the Oregon Coast Range. According to our formulation, which provides an explicit linkage for relating the distribution of biota to hillslope processes, the degree of hilltop convexity varies nonlinearly with the ratio of erosion rate to maximum soil production rate, highlighting the profound influence of soil depth on hillslope evolution. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.