An Analysis of the Debris Flow Disaster in the Harihara River Basin

  1. William McCaffrey,
  2. Ben Kneller and
  3. Jeff Peakall
  1. H. Nakagawa,
  2. T. Takahashi and
  3. Y. Satofuka

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304275.ch3

Particulate Gravity Currents

Particulate Gravity Currents

How to Cite

Nakagawa, H., Takahashi, T. and Satofuka, Y. (2001) An Analysis of the Debris Flow Disaster in the Harihara River Basin, in Particulate Gravity Currents (eds W. McCaffrey, B. Kneller and J. Peakall), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304275.ch3

Editor Information

  1. School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK

Author Information

  1. Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji City, Kyoto 611-0011, Japan

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 24 APR 2001

ISBN Information

Print ISBN: 9780632059218

Online ISBN: 9781444304275

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Keywords:

  • analysis of debris flow disaster in Harihara River basin;
  • severe debris flow disaster on Harihara River, Japan;
  • flood runoff analysis;
  • debris flow simulation;
  • calculated and observed sediment volumes of deposits;
  • depositional process of flow - satisfactorily expressed by numerical simulation model

Summary

A severe debris flow disaster occurred on the Harihara River, Japan about midnight of July 10, 1997. Twenty-one people were killed, and 18 houses destroyed by this flow which was caused by a massive slope failure with a sediment volume of approximately 160 000 m3 following heavy rainfall. Residents were aware that an extraordinary phenomenon was occurring in the river but did not take refuge, resulting in the large number of human casualties. A numerical simulation model is developed to explain the behaviour and the depositional processes of the debris flow. In this model, a debris flow is considered to move as a continuous fluid until just before it stops, and a system of depth-averaged two-dimensional momentum and mass conservation equations for fluid flow are used which take into account variation in the concentration of the sediment fraction owing to the deposition of sediment and variation in the discharge. To estimate the amount of sediment deposited, deposition equations were introduced for a fully developed debris flow, an immature debris flow and a turbulent flow. The models are in general agreement with actual phenomena such as the sediment deposition area and thickness of the deposit.