Flood Simulation in the Colombian Andean Region Using UAV-based LiDAR : Minor Field Study in Colombia

Sammanfattning: Flooding is a worldwide problem that every year causes substantial damage for the environment and stakeholders nearby, and this impact relates to several of the United Nations Sustainable Development Goals. Colombia is specially prone to flooding as 17% of its surface area is at risk of extreme flooding. In addition, there is something called a POT (plan de ordenamiento territorial) for every municipality in Colombia, which states how the territory should be managed. For this project the rivers were of particular interest, and the POT states that no temporary or permanent constructions are allowed within 30 meters on either side of a river. The purpose of this report was to investigate and analyze the possibilities of using UAV (unmanned aerial vehicle) -based photogrammetry and UAV-based LiDAR (light detection and ranging) technology to gather sufficient data for a model that could simulate different flooding scenarios in the examined area. Data from the UAV-based photogrammetry resulted in a complete visual overview of the examined area. The data gathered from the UAV-based light detection and ranging resulted in an accurate point cloud that could be processed into a DTM (digital terrain model) where three different flooding scenarios were simulated. The simulations and the visual model showed that majority of people in theexamined area were disobeying the POT and the 30 meter rule, therefore being in risk of flooding and impacting the natural diversity of the body of water. The simulation also showed that stakeholders close to the body of water were affected for each of the three different water level scenarios. In some cases, it was only vegetation and crops that got affected by the flooding scenario, while in other cases entire structures and buildings were damaged due to the increase of water level. To complement the flooding scenarios, interviews were conducted with people that have good knowledge of the area and of ecology, resulting in a stakeholder analysis. This provided an additional depth to the analysis and showed the complexity in the management of flooding in the area.