Erosion thresholds and land surface morphology

Abstract

Research Article| August 01, 1992 Erosion thresholds and land surface morphology William E. Dietrich; William E. Dietrich 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Cathy J. Wilson; Cathy J. Wilson 2Australian Center for Catchment Hydrology, CSIRO, Canberra, A.C.T. 2601, Australia Search for other works by this author on: GSW Google Scholar David R. Montgomery; David R. Montgomery 3Department of Geological Sciences, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar James McKean; James McKean 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Romy Bauer Romy Bauer 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Author and Article Information William E. Dietrich 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Cathy J. Wilson 2Australian Center for Catchment Hydrology, CSIRO, Canberra, A.C.T. 2601, Australia David R. Montgomery 3Department of Geological Sciences, University of Washington, Seattle, Washington 98195 James McKean 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Romy Bauer 1Department of Geology and Geophysics, University of California, Berkeley, California 94720 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (8): 675–679. https://doi.org/10.1130/0091-7613(1992)020<0675:ETALSM>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation William E. Dietrich, Cathy J. Wilson, David R. Montgomery, James McKean, Romy Bauer; Erosion thresholds and land surface morphology. Geology 1992;; 20 (8): 675–679. doi: https://doi.org/10.1130/0091-7613(1992)020<0675:ETALSM>2.3.CO;2 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 SocietyGeology Search Advanced Search Abstract We propose a graphical technique to analyze the entirety of landforms in a catchment to define quantitatively the spatial variation in the dominance of different erosion processes. High-resolution digital elevation data of a 1.2 km2 hilly area where the channel network had been mapped in the field were used in the digital terrain model, TOPOG, to test threshold theories for erosion. The land surface was divided into ∼20 m2 elements whose shapes were then classified as convergent, planar, or divergent. The entire landscape plotted on a graph of area per unit contour length against surface gradient shows each planform plotting as a separate field. A simple steady-state hydrologic model was used to predict zones of saturation and areas of high pore pressure to mimic the extreme hydrologic events responsible for erosive instability of the land surface. The field observation that saturation overland flow is rare outside convergent zones provided a significant constraint on the hydrologic parameter in the model. This model was used in threshold theories to predict areas of slope instability and areas subject to erosion by saturation overland flow, both of which can contribute to channel initiation. The proportion of convergent elements predicted to exceed the threshold varies greatly with relatively small changes in surface resistance, demonstrating a high sensitivity to land use such as cattle grazing. Overall, the landscape can be divided, using erosion threshold lines, into areas prone to channel instability due to runoff and stable areas where diffusive transport predominates. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.