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Journal of Mountain Science

, Volume 10, Issue 5, pp 716–723 | Cite as

Long-term impact of extra sediment on notches and incised meanders in the Hoshe River, Taiwan

  • Su-Chin Chen
  • Chun-Hung Wu
  • Yi-Chiung ChaoEmail author
  • Pei-Yu Shih
Article

Abstract

The extra sediment load induced by typhoons and rainstorms in the Heshe River, Taiwan, are the principal reason for severe sediment-related disasters. The total sediment load during Typhoon Morakot in 2009 was 31 × 106 m3, accounting for 95% of the annual sediment discharge. Large amounts of sediment load entered the Hoshe River, causing the braiding index (BI) to increase. Subsequently, the BI became positively correlated with the channel width in the Hoshe River. The specific typhoon and rainstorm events decreased after Typhoon Morakot, the sediment input decreased, inducing the fluvial morphology of the braided river to develop into a meandering river. The extra sediment load induced the deposition depth to increase and produce a headward deposition in the main channel and its tributaries. In addition, the river bend and the topographical notch restrained the sediment from moving downstream and being stored locally, indirectly increasing the erosion density of the river banks from 2.5 to 10.5 times.

Keywords

Extra sediment load River morphology Braiding index 

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Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Su-Chin Chen
    • 1
  • Chun-Hung Wu
    • 2
  • Yi-Chiung Chao
    • 1
    • 3
    Email author
  • Pei-Yu Shih
    • 1
  1. 1.Dept. of Soil and Water ConservationNational Chung Hsing UniversityTaichungChinese Taipei
  2. 2.Water Resources Engineering and ConservationFeng Chia UniversityTaichungChinese Taipei
  3. 3.TaichungTaiwan

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