A novel approach for quantifying similarities between different debris flow sites using field investigations and numerical modelling

Abstract

Debris flows are geomorphological processes that affect the landscape evolution process of any region. In this study, an integrated methodology is proposed to identify the chance of further debris flows and quantify the similarities between debris flow locations, materials and rheology, using field and laboratory investigations and remote sensing data. The method was tested for four failure‐triggered debris flow sites in the Western Ghats of India, using dimensionless parametric similarity values ranging from 0 to 1. The maximum parametric similarity was observed as 0.84 when comparing the flow accumulation values of Sites 3 and 4, and the maximum overall site similarity was 0.68. The calibrated rheological parameters of one site were found to be satisfactory in modelling the shape of debris flow at all other sites. The findings can be used to identify similar hotspots in the region and to simulate debris flows for quantitative hazard assessment.

Numerical Modelling of Debris Flows for Simulation-Based Decision Support: An Indian Perspective

“…The engineering properties of soil or rock control the flow dynamics in several ways. Geotechnical and geophysical investigations are also crucial in understanding the erosion and depositions happened in the field after a debris flow event [55]. This information is critical in back analysis process, especially when model parameters need to be calibrated.…”

“…An example is shown in Fig. 8, from Puthumala, Kerala, India [55], where more than 60 houses (red outline in Fig. 8a) were completely destroyed in a debris flow event.…”