Role of Debris Flow in Wayanad Landslides

January 14, 2025

Recent events in Wayanad have tells the urgent need for enhanced disaster management strategies. A study conducted in response to the catastrophic landslides of July 2024 has provided vital information about the behaviour of rapid debris flows. This research involved multiple prestigious institutions and aimed to better understand the dynamics of natural disasters in mountainous regions.

Study Overview

The collaborative research included contributions from the University of Kerala, Indian Institute of Science Education and Research, Mohali, University of Mississippi, British Geological Survey, and T.K.M. College of Engineering. Published in *Nature Natural Hazards*, the study focused on tracking debris flow paths using advanced modelling techniques. It aimed to identify how speed, pressure, and material accumulation contribute to the destruction caused by landslides.

Key Findings

The study revealed that lower elevations are particularly vulnerable to debris flow events. By employing crowd-sourced data and Rapid Mass Movement Simulation (RAMMS), researchers mapped areas of intense activity. These maps indicated regions at high risk of damage, confirming the deposition of debris at lower elevations. This information is crucial for understanding future hazards downstream.

Vulnerability Mapping

Creation of detailed vulnerability maps is crucial for efficient disaster management. These maps depict potential run-out paths of debris flows, offering guidance for urban planning and disaster mitigation. Avoiding development in high-risk zones could reduce destruction and loss of life.

Historical Context

The study also noted a concerning trend regarding the path of the recent debris flow. It mirrored the trajectory of a devastating landslide from July 1984, which resulted in 14 fatalities, as well as a smaller event in 2019. This historical context reinforces the need for ongoing research and monitoring in the region.

Importance of Early Warning Systems

Early warning systems are crucial for reducing the impact of debris flows. The research advocates for the installation of rainfall and soil moisture monitoring stations. By establishing thresholds, authorities can alert communities about imminent hazards. This proactive approach could facilitate timely evacuations and other safety measures, ultimately saving lives.

Threshold Volume

A related study investigated 66 debris flows along the Western Ghats in Kerala. It established that a threshold volume of 7,072 cubic metres is critical for predicting debris flow paths. Flows exceeding this volume tend to follow the steepest hill slope stream channels, while smaller flows are more likely to adhere to existing stream channels.

RAMMS – Rapid Mass Movement Simulation, a modelling tool.
Sajin Kumar K.S – Co-author and Assistant Professor of Geology.
Wayanad – A mountainous district in Kerala, India.
Threshold Volume – 7,072 cubic metres indicates flow path behaviour.
Nature Natural Hazards – Journal where the study was published.

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