Debris flow disaster risk analysis and modeling via numerical simulation and land use assessment

Abstract

To mitigate the risk of debris flows, quantitative risk assessments for different land use types are quite significant. However, with respect to debris flows, no sound relationship has so far been established between risks and different land use types. This study developed a method of debris flow risk assessment by incorporating numerical simulations with land use types. First, the key debris flow intensities for different return periods, including movement velocities and maximum flow depths, were identified via numerical simulations. Second, a debris flow hazard classification model based on a combination of the debris flow intensity and the return period was established to assess debris flow hazard degree. Then, the land use distribution within the inundated areas was itemized via the interpretation of remote sensing and field surveys, and the debris flow vulnerability was determined by the degree of functional damage or the cost of recovery of land uses caused under a given hazard. Finally, the potential debris flow risk zones were identified and mapped by combining debris flow hazard and vulnerability. The methodology was applied and verified in a small debris flow watershed in China. The proposed methodology can be performed effectively to conduct debris flow risk analysis and can be widely employed for debris flow mitigation.