Approaches for Prediction of Debris Flow Runout

Debris flows are one of the destructive forms of landslides that are capable of traveling a long distance in comparison to other forms of mass movements. Debris flows are responsible for the loss of lives and property as well as the degradation of the environment in mountainous regions worldwide. The destructive potential of debris flows can be attributed to the flow velocity, flow as well as deposition height, and deposition characteristics. Runout modelling is carried out to derive the flow intensity parameters (velocity, height & pressure) and the demarcation of potential areas to be affected in the post-mobilization stage. Different available approaches for the prediction of debris flow runout can be classified as empirical, numerical, and experimental. Empirical approaches need well-documented historical data for the runout estimation. Non-availability of historical data on debris flow events reduces the accuracy of the prediction. Numerical models are useful for back analysis of past events and prediction of futuristic scenarios for hazard assessment. On the other hand, experimental studies are useful for detailed study on debris flow dynamics and runout as well as deposition mechanisms. This paper reviews different available approaches for the prediction of debris flow runout and the applicability of these approaches has been examined. The limitations and advantages of runout modelling approaches have also been highlighted. The runout modelling of debris flows should be carried out for effective debris flow hazard vulnerability and risk assessment.