Quantification of the damming and sediment trapping capacity of landslides and their dammed lakes: the example of the Hintersee landslide dam
- 1Department of Environment and Biodiversity, Geology Division, Paris-Lodron-University of Salzburg, 5020 Salzburg, Austria
- 2Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA (aargenti@umich.edu)
- 3Géosciences Rennes, OSUR, CNRS, Université de Rennes 1, Rennes, France
- 4Near Surface Geophysics, Institute of Earth and Environmental Sciences, Faculty of Environment and Natural Resources, 79104 Freiburg, Germany
- 5Centre for Interdisciplinary Mountain Research, University of Lausanne, 1967 Bramois, Switzerland
- 6Department of Geoinformatics - ZGIS, University of Salzburg, 5020 Salzburg, Austria
- 7Berchtesgaden National Park, 83471 Berchtesgaden, Germany
- 8Ecosystem Dynamics and Forest Management Group, Technical University of Munich, 85354 Freising, Germany
Perennial landslide dams interrupt the sediment connectivity of rivers. Although most landslide dams do not persist for more than a few days, those that do can exhibit significant sediment trapping capacity. While water can pass through or over the dam, the sediment load is trapped upstream of the dam until the dam breaks or gradually erodes, or is completely filled with deposits. The volume of sediment stored in this way can reach up to three times the volume of impounded water, as we find by back-analyzing the lake Hintersee in southeastern Germany. In this work, we reconstruct the pre-landslide topography using Petrel and then use the Gerris shallow-water flow solver with a Voellmy rheology to back-analyze this landslide-dammed lake in the Bavarian Alps. We test several landslide release scenarios and different landslide rheologies to obtain the best-fitting reconstruction of the dam topography. We then fill the landslide dam with water and sediment using simple slope algorithms and validate the results against the current topography. Finally, we compare the landslide deposit thicknesses, water depths, and trapped sediment thicknesses of our different scenarios in order to provide new insight into the damming and sediment trapping capacity of landslides.
How to cite: Argentin, A.-L., Hauthaler, T., Liebl, M., Robl, J., Hergarten, S., Prasicek, G., Salcher, B., Hölbling, D., Pfalzner-Gibbon, C., Mandl, L., Maroschek, M., Abad, L., and Dabiri, Z.: Quantification of the damming and sediment trapping capacity of landslides and their dammed lakes: the example of the Hintersee landslide dam, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9848, https://doi.org/10.5194/egusphere-egu23-9848, 2023.