Parameterizing a physically based shallow landslide model in a data poor region

Abstract

Shallow landslides and consequent debris flows are an increasing concern in the Western Ghats of Kerala, India. Their increased frequency has been associated with deforestation and unfavourable land-use practices in cultivated areas. In order to evaluate the influence of vegetation on shallow slope failures a physically based, dynamic and distributed hydrological model (STARWARS) coupled with a probabilistic slope stability model (PROBSTAB) was applied to the upper Tikovil River basin (55·6 km 2 ). It was tuned with the limited evidence of groundwater conditions during the monsoon season of 2005 and validated against observed landslide activity in the hydrological year 2001-2002. Given the data poor conditions in the region some modifications to the original model were in order, including the estimation of parameters on the basis of generalized information from secondary sources, pedo-transfer functions, empirical equations and satellite remote sensing data. Despite the poor input, the model captured the general temporal and spatial pattern of instability in the area. Sensitivity analysis proved root cohesion, soil depth and angle of internal friction as the most dominant parameters influencing slope stability. The results indicate the importance of root cohesion in maintaining stability and the critical role of the management of rubber plantations in this. Interception and evapotranspiration showed little influence on the development of failure conditions. The study also highlights the importance of high resolution digital terrain models for the accurate mechanistic prediction of shallow landslide initiation.

A conceptual model of the hydrological influence of fissures on landslide activity

“…Since its development, the STARWARS model has been used by many researchers to study different hydrological and ecological issues for both synthetic and real case studies ( Van Beek, 2002;Malet et al, 2005;Kuriakose et al, 2009;Brolsma, 2010). In 2005, Malet and co-authors applied the STARWARS model to the Super-Sauze landslide using the simple bypass flow scheme representing only shallow bypassing flow without fissure-matrix interaction (Fig.…”

Automatic and Self-Adaptive Stem Reconstruction in Landslide-Affected Forests

“…Climate change adaption and natural disasters in these regions are receiving considerable attention [10]. For example, recently-developed dynamic slope stability models (e.g., [11,12]) studied the interdependencies of different processes, including deforestation or afforestation. Detailed stem volume and biomass information at single tree level can greatly benefit and facilitate such studies [13].…”

Quantitative estimation of landslide risk from rapid debris slides on natural slopes in the Nilgiri hills, India

“…The question remains, however, how to incorporate these for the many possible landslide initiation areas in a quantitative susceptibility map with many mapping units having different spatial probabilities (van Westen et al, 2006). Process-based methods have been used to demarcate landslide hazard areas but they experience serious problems with parameterization, which makes their application problematic over larger areas, especially in a heterogeneous terrain setting (Kuriakose et al, 2009). One way to include run-out distance in risk analysis, over a large area, is to use empirical relationships such as the identification of all hazardous zones likely to affect the elements at risk that are located down slope of the landslide initiation areas, followed by a loss estimate for each element separately.…”