Abstract
Landslides are the main source of sediment in most mountain ranges. Rivers then act as conveyor belts, evacuating landslide-derived sediment. Sediment dynamics are known to influence landscape evolution through interactions among landslide sediment delivery, fluvial transport and river incision into bedrock. Sediment delivery and its interaction with river incision therefore control the pace of landscape evolution and mediate relationships among tectonics, climate and erosion. Numerical landscape evolution models (LEMs) are well suited to study the interactions among these surface processes. They enable evaluation of a range of hypotheses at varying temporal and spatial scales. While many models have been used to study the dynamic interplay between tectonics, erosion and climate, the role of interactions between landslide-derived sediment and river incision has received much less attention. Here, we present HyLands, a hybrid landscape evolution model integrated within the TopoToolbox Landscape Evolution Model (TTLEM) framework. The hybrid nature of the model lies in its capacity to simulate both erosion and deposition at any place in the landscape due to fluvial bedrock incision, sediment transport, and rapid, stochastic mass wasting through landsliding. Fluvial sediment transport and bedrock incision are calculated using the recently developed Stream Power with Alluvium Conservation and Entrainment (SPACE) model. Therefore, rivers can dynamically transition from detachment-limited to transport-limited and from bedrock to bedrock-alluvial to fully alluviated states. Erosion and sediment production by landsliding are calculated using a Mohr-Coulomb stability analysis, while landslide-derived sediment is routed and deposited using a multiple-flow-direction, nonlinear deposition method. We describe and evaluate the HyLands 1.0 model using analytical solutions and observations. We first illustrate the functionality of HyLands to capture river dynamics ranging from detachment-limited to transport-limited conditions. Second, we apply the model to a portion of the Namche Barwa massif in eastern Tibet and compare simulated and observed landslide magnitude-frequency and area-volume scaling relationships. Finally, we illustrate the relevance of explicitly simulating landsliding and sediment dynamics over longer timescales for landscape evolution in general and river dynamics in particular. With HyLands we provide a new tool to understand both the long- and short-term coupling between stochastic hillslope processes, river incision and source-to-sink sediment dynamics.
.| Original language | English |
|---|---|
| Pages (from-to) | 3863-3886 |
| Journal | Geoscientific Model Development |
| Volume | 13 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 31 Aug 2020 |
| Externally published | Yes |
Funding
Acknowledgements. Benjamin Campforts received funding from the Research Foundation Flanders, FWO grant agreement no. 12Z6518N. Charles M. Shobe received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 833132. Philippe Steer and Dimitri Lague have received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 803721). Financial support. This research has been supported by the FWO – Research Foundation Flanders (grant no. FWO – Postdoctoral fellowship/12Z6518N), the H2020 Marie Skłodowska-Curie Actions (grant no. STRATASCAPE (833132)) and the H2020 European Research Council (grant no. FEASIBLe (803721)).
| Funders | Funder number |
|---|---|
| Marie Skłodowska-Curie | |
| National Science Foundation | 1831623 |
| Horizon 2020 Framework Programme | 803721 |
| H2020 European Research Council | |
| H2020 Marie Skłodowska-Curie Actions | 833132 |
| European Research Council | |
| Fonds Wetenschappelijk Onderzoek | 12Z6518N |