Landslide Hazard and Risk Management Framework for Alaknanda Basin in the Indian Himalayan Region

Landslides in the Indian Himalayan Region (IHR) primarily result from extreme precipitation events, distinctive topography, and inadequate soil and water conservation practices. Managing such calamity is a daunting task. This study advocates an innovative rule-based approach for Landslide Risk Management (LRM). A distinct feature of this approach is a likelihood-consequence matrix (LCM) that formulates 25 combinations to segregate the basin into four risk zones: low, moderate, high, and extreme. Each combination aligns with a specific landslide likelihood and corresponding damage. Furthermore, integrating Geographic Information System (GIS) technology ensures effective spatial data management and visualization. The proposed rule-based model offers scalability, adaptability, and user-friendliness. The proposed methodology allows the stakeholders to take informed decisions for effective disaster response, evacuation plans, road closures, and long-term mitigation strategies. To illustrate the proposed methodology, the Alaknanda basin in the Indian Himalayan Region is considered a case study. The methodology adopted in this study seamlessly integrates the Likelihood of landslides depicted by Landslide Hazard Maps, with the anticipated Consequences, represented through comprehensive Soil Erosion Maps. It is observed that, 32.0% of the area falls under “Unlikely” likelihood, with 57.3% facing “Minor” consequences. “Low” risk covers nearly half the area (49.7%), while “Moderate,” “High,” and “Extreme” risks constitute 25.2%, 17.6%, and 7.5% respectively. Such an approach offers an expansive analysis, enriching the understanding of inherent vulnerabilities and potential impacts within the Alaknanda Basin. It is hoped that the proposed system will help planners and decision-makers in effective risk management on a scientific basis.