Estimation of debris flow sedimentation volume through numerical modelling

Abstract

Implementation of potential debris flow hazard in Malaysia has been conducted by Jabatan Kerja Raya in 2011. However, evaluation of this hazard level cannot deny the consequent to the nearest facilities. Thus, run-out analysis based on numerical modelling is the easiest and competent way to evaluate the risk level. There are more than 10 cases reported regarding debris flow occurrence from 1995 until 2015 in Malaysia. All these cases have caused severe damage to facilities and have involved a huge number of fatalities. Hence, an effective strategy is required on reducing the impact from these damages especially debris flow catastrophe. One of the structural measures for debris flow is a Sabo dam. This study presents a study on debris flow sedimentation volume with and without Sabo dam by numerical simulation using Kanako 2D software. Kanako 2D software is widely used in Japan and it is equipped with graphical user interface. A crossed verification upon numerical modelling and actual field data collection, and mitigation situation model that include Sabo dam has been conducted. Results show that Kanako 2D software has a precise output where the sedimentation volume is slightly higher in the range of 5 to 15 % compared to actual field data. It also proved that Sabo dam can reduce the impact of debris flow as it can bear the sedimentation volume about 91%.