Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments
<p>Tectonic and geomorphic processes drive landscape evolution over different spatial and temporal scales. In mountainous environments, river incision sets the pace of landscape evolution, and hillslopes respond to channel incision by, e.g., gully retreat, bank erosion, and landslides. Sedimen...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-09-01
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| Series: | Solid Earth |
| Online Access: | https://www.solid-earth.net/10/1489/2019/se-10-1489-2019.pdf |
| _version_ | 1818139764589592576 |
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| author | F. Clapuyt V. Vanacker M. Christl K. Van Oost K. Van Oost F. Schlunegger |
| author_facet | F. Clapuyt V. Vanacker M. Christl K. Van Oost K. Van Oost F. Schlunegger |
| author_sort | F. Clapuyt |
| collection | DOAJ |
| description | <p>Tectonic and geomorphic processes drive landscape
evolution over different spatial and temporal scales. In mountainous
environments, river incision sets the pace of landscape evolution, and
hillslopes respond to channel incision by, e.g., gully retreat, bank erosion, and landslides. Sediment produced during stochastic landslide events leads
to mobilization of soil and regolith on the slopes that can later be
transported by gravity and water to the river network during phases of
hillslope–channel geomorphic coupling. The mechanisms and scales of sediment
connectivity mitigate the propagation of sediment pulses throughout the
landscape and eventually drive the contribution of landslides to the overall
sediment budget of mountainous catchments. However, to constrain the timing
of the sediment cascade, the inherent stochastic nature of sediment and
transport through landsliding requires an integrated approach accounting for
different space scales and timescales. In this paper, we examine the sediment
production on hillslopes and evacuation to the river network of one
landslide, i.e. the Schimbrig earthflow, affecting the Entle River catchment
located in the foothills of the Central Swiss Alps. We quantified sediment
fluxes over annual, decadal, and millennial timescales using respectively unmanned aerial vehicle (UAV)–structure-from-motion (SfM) techniques, classic photogrammetry, and in situ produced cosmogenic
radionuclides. At the decadal scale, sediment fluxes quantified for the
period 1962–1998 are highly variable and are not directly linked to the
intensity of sediment redistribution on the hillslope. At the millennial
scale, landslide occurrence perturbs the regional positive linear
relationship between sediment fluxes and downstream distance as the
landslide-affected Schimbrig catchment is characterized by a decrease in
sediment fluxes and a strong variability. Importantly, the average decadal
sediment flux of the Schimbrig catchment is 2 orders of magnitude higher
than millennial sediment fluxes computed over the same spatial extent. The
discrepancy between decadal and millennial sediment fluxes, combined to the
highly variable annual sediment evacuation from the hillslopes to the
channel network suggest that phases of hillslope–channel geomorphic coupling
are short and intermittent. During most of the time, the first-order
catchments are transport-limited and sediment dynamics in the headwaters are
uncoupled from the fluvial systems. In addition, our unique spatio-temporal
database of sediment fluxes highlights the transient character of the
intense geomorphic activity of the Schimbrig catchment in a regional
context. Its decadal sediment flux is of the same order of magnitude as the background sediment flux going out of the entire Entle River catchment.
Over the last 50 years, the Schimbrig catchment, which represents ca. 1 %
of the entire study area, provides 65 % of the sediments that the entire
Entle catchment will supply over the millennial scale. These results suggest
that episodic supply of sediment from landslides during intermittent phases
of hillslope–channel geomorphic coupling are averaged out when considering
sediment fluxes at longer timescales and larger spatial scales.</p> |
| first_indexed | 2024-12-11T10:33:17Z |
| format | Article |
| id | doaj.art-6a9b2e849ab44b2facfbe39c571a4f4c |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-12-11T10:33:17Z |
| publishDate | 2019-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-6a9b2e849ab44b2facfbe39c571a4f4c2022-12-22T01:10:50ZengCopernicus PublicationsSolid Earth1869-95101869-95292019-09-01101489150310.5194/se-10-1489-2019Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchmentsF. Clapuyt0V. Vanacker1M. Christl2K. Van Oost3K. Van Oost4F. Schlunegger5Earth and Life Institute, Georges Lemaître Centre for Earth and Climate Research, Université catholique de Louvain, Place Pasteur, 3 Bte L4.03.08, 1348 Louvain-la-Neuve, BelgiumEarth and Life Institute, Georges Lemaître Centre for Earth and Climate Research, Université catholique de Louvain, Place Pasteur, 3 Bte L4.03.08, 1348 Louvain-la-Neuve, BelgiumLaboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich, SwitzerlandEarth and Life Institute, Georges Lemaître Centre for Earth and Climate Research, Université catholique de Louvain, Place Pasteur, 3 Bte L4.03.08, 1348 Louvain-la-Neuve, BelgiumFonds de la Recherche Scientifique - FNRS, Rue d'Egmont, 5, 1000 Brussels, BelgiumInstitut für Geologie, Universität Bern, Baltzerstrasse 1+3, 3012 Bern, Switzerland<p>Tectonic and geomorphic processes drive landscape evolution over different spatial and temporal scales. In mountainous environments, river incision sets the pace of landscape evolution, and hillslopes respond to channel incision by, e.g., gully retreat, bank erosion, and landslides. Sediment produced during stochastic landslide events leads to mobilization of soil and regolith on the slopes that can later be transported by gravity and water to the river network during phases of hillslope–channel geomorphic coupling. The mechanisms and scales of sediment connectivity mitigate the propagation of sediment pulses throughout the landscape and eventually drive the contribution of landslides to the overall sediment budget of mountainous catchments. However, to constrain the timing of the sediment cascade, the inherent stochastic nature of sediment and transport through landsliding requires an integrated approach accounting for different space scales and timescales. In this paper, we examine the sediment production on hillslopes and evacuation to the river network of one landslide, i.e. the Schimbrig earthflow, affecting the Entle River catchment located in the foothills of the Central Swiss Alps. We quantified sediment fluxes over annual, decadal, and millennial timescales using respectively unmanned aerial vehicle (UAV)–structure-from-motion (SfM) techniques, classic photogrammetry, and in situ produced cosmogenic radionuclides. At the decadal scale, sediment fluxes quantified for the period 1962–1998 are highly variable and are not directly linked to the intensity of sediment redistribution on the hillslope. At the millennial scale, landslide occurrence perturbs the regional positive linear relationship between sediment fluxes and downstream distance as the landslide-affected Schimbrig catchment is characterized by a decrease in sediment fluxes and a strong variability. Importantly, the average decadal sediment flux of the Schimbrig catchment is 2 orders of magnitude higher than millennial sediment fluxes computed over the same spatial extent. The discrepancy between decadal and millennial sediment fluxes, combined to the highly variable annual sediment evacuation from the hillslopes to the channel network suggest that phases of hillslope–channel geomorphic coupling are short and intermittent. During most of the time, the first-order catchments are transport-limited and sediment dynamics in the headwaters are uncoupled from the fluvial systems. In addition, our unique spatio-temporal database of sediment fluxes highlights the transient character of the intense geomorphic activity of the Schimbrig catchment in a regional context. Its decadal sediment flux is of the same order of magnitude as the background sediment flux going out of the entire Entle River catchment. Over the last 50 years, the Schimbrig catchment, which represents ca. 1 % of the entire study area, provides 65 % of the sediments that the entire Entle catchment will supply over the millennial scale. These results suggest that episodic supply of sediment from landslides during intermittent phases of hillslope–channel geomorphic coupling are averaged out when considering sediment fluxes at longer timescales and larger spatial scales.</p>https://www.solid-earth.net/10/1489/2019/se-10-1489-2019.pdf |
| spellingShingle | F. Clapuyt V. Vanacker M. Christl K. Van Oost K. Van Oost F. Schlunegger Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments Solid Earth |
| title | Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments |
| title_full | Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments |
| title_fullStr | Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments |
| title_full_unstemmed | Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments |
| title_short | Spatio-temporal dynamics of sediment transfer systems in landslide-prone Alpine catchments |
| title_sort | spatio temporal dynamics of sediment transfer systems in landslide prone alpine catchments |
| url | https://www.solid-earth.net/10/1489/2019/se-10-1489-2019.pdf |
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