Characteristics of rainfall triggering of debris flows in the Chenyulan watershed, Taiwan

J. C. Chen, C. D. Jan, W. S. Huang

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

This paper reports the variation in rainfall characteristics associated with debris flows in the Chenyulan watershed, central Taiwan, between 1963 and 2009. The maximum hourly rainfall Im, the maximum 24 h rainfall Rd, and the rainfall index RI(defined as the product RdIm were analysed for each rainfall event that triggered a debris flow within the watershed. The corresponding number of debris flows initiated by each rainfall event (N) was also investigated via image analysis and/or field investigation. The relationship between N and RI was analysed. Higher RI of a rainfall event would trigger a larger number of debris flows. This paper also discusses the effects of the Chi-Chi earthquake (CCE) on this relationship and on debris flow initiation. The results showed that the critical RI for debris flow initiation had significant variations and was significantly lower in the years immediately following the CCE of 1999, but appeared to revert to the pre-earthquake condition about five years later. Under the same extreme rainfall event of RI Combining double low line 365 cm2 h-1, the value of N in the CCE-affected period could be six times larger than that in the non-CCE-affected periods.

Original languageEnglish
Pages (from-to)1015-1023
Number of pages9
JournalNatural Hazards and Earth System Science
Volume13
Issue number4
DOIs
Publication statusPublished - 2013

All Science Journal Classification (ASJC) codes

  • Earth and Planetary Sciences(all)

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