Investigating sediment dynamics in a landslide-dominated catchment by modeling landslide area and fluvial sediment export

Tse Yang Teng, Jr Chuan Huang, Tsung Yu Lee*, Yi Chin Chen, Ming Young Jan, Cheng Chien Liu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Few models are capable of simultaneously simulating the sequences of landslide occurrence and sediment export. Quantification of the temporarily stored sediment within the watershed plays a key role to link hillslope landslides with fluvial sediment export. In this study, two coupled models were proposed to simulate time-series total landslide area and the subsequent sediment export on a daily basis with only the inputs of rainfall and runoff. The landslide model considers per-existing and models new landslide, and the sediment transport model incorporates a sediment storage variable. The landslide and sediment transport model were well evaluated with Nash-Sutcliffe efficiency (EC) of 0.89 and logarithmic Nash-Sutcliffe efficiency (EClog ) of 0.90, respectively, in the Tsengwen Reservoir watershed in southern Taiwan by using long-term observed data (2005–2015). It is found that reactivated landslides were up to 72% of the pre-landslide area, which contributed sediment comparable to the new landslide. Besides, the landslide model indicates that pre-landslide area controls the total landslide area but when rainfall is large it takes control in turn. With the simulation of sediment storage, the sediment transport model can well simulate the sediment export after the catastrophic event (typhoon Morakot in 2009). During the post-Morakot period, small rainfall and runoff can lead to high sediment export owing to the storage of Morakot-triggered landslide. This model will be a useful tool to diagnose the sediment dynamics in the watershed.

Original languageEnglish
Article number2907
Pages (from-to)1-20
Number of pages20
JournalWater (Switzerland)
Volume12
Issue number10
DOIs
Publication statusPublished - 2020 Oct

Keywords

  • Landslide
  • Sediment storage
  • Sediment transport
  • Taiwan

ASJC Scopus subject areas

  • Biochemistry
  • Geography, Planning and Development
  • Aquatic Science
  • Water Science and Technology

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