Numerical Modeling of Landslide Susceptibility: A Case Study for Uma Oya Catchment, Sri Lanka

Abstract

Landslide susceptibility being a severe threat abundant worldwide, they tend to occur in a variety of geological and environmental settings, while imposing devastating consequences for both human life and infrastructure. Characterized by a unique combination of geological and climatic factors that are conducive to slope instability, the central highlands of Sri Lanka, are more frequently exposed to the risk of slope failures compared to other regions in the country. Provided the necessity of comprehensive knowledge and understanding of the related hydro-geological phenomena underlying the specific geological setting, developing a deterministic landslide model finds a high level of applicability and usability in disaster risk mitigation strategies, which sets the objective of this research. The study enabled the development of an integrated numerical model within the geographical information system environment, to simulate the regional hydro-geological processes to predict the groundwater levels and the associated measures of slope stability to map the distribution of landslide susceptibility within the region. Backed by a recovery rate of 79% in predicted water table elevations, the model's predictions on slope stability were in agreement with a known past landslide occurrence within the period of simulation. The developed model with enhanced features of adaptability, being the key outcome, this research is aimed at setting an initiative that with the potential to be developed into an advanced modeling environment for landslide susceptibility evaluations, enabling effective decision-making in the future.