The advent of technological advances in the field of digital photogrammetry and the development of Unmanned Aircraft Systems (UAS) with Very High Resolution (VHR) cameras, it has become recurrent the use of these technologies in the field of forest inventories for the determination of vegetation cover due to the optimization of resources in forest characterization. Additionally, UAS have recently been used for a variety of geoscientific applications including landslide monitoring using Structure-from-motion (SfM) algorithms that facilitate the production of detailed topographic models from aerial photographs, which are used to measure ground displacements. In this paper, it was used a PhoDAR (Photogrammetric Detection and Ranging) dataset (3D point cloud and VHR imagery) acquired by mean of a UAS, in the southwest zone of Medellín City-Colombia where the most frequent landslides are shallow and triggered by rainfall. For the estimation of the tree roots effects on the shallow landslide assessment on a natural slope, SfM process was developed, obtaining digital terrain models and orthophotomosaics of 8cm-pixel. Slopes with gradients up to 30% on residual soils characterize the study area, having about of 30% of forest cover consisting predominantly of Eucalyptus and Coniferous forests. The proposed workflow was implemented on a GIS platform, and considers the extraction of the tree heights by generating a Canopy Height Model (CHM), while for the delineation of the tree crown a process of image segmentation was developed. Once the vegetation has been characterized using Remote Sensing (RS) products and dendrometric relationships, the Limit Equilibrium Method (LEM) was used to evaluate slope stability considering the effect of vegetation (trees). The results indicate that the proposed workflow allows to obtain adequate stability indicators for the estimation of tree roots contribution, and additionally this RS technique allows saving resources in this kind of analysis. It is important to highlight that the presence of vegetation reduces the likelihood of mass failure due to reinforcement of slope soils by tree roots.
|Journal||Proceedings of the International Conference on Natural Hazards and Infrastructure|
|State||Published - 2019|
|Event||2nd International Conference on Natural Hazards and Infrastructure, ICONHIC 2019 - Chania, Greece|
Duration: 23 Jun 2019 → 26 Jun 2019
- Slope stability
- Tree roots
- Unmanned Aircraft Systems