GIS-based Multi-Criteria Decision Analysis (MCDA) framework for Flood Risk Assessment in the Thermi Basin

Sammanfattning

Flood risk is influenced not only by climate change but also underlying factors including unplanned urbanization, environmental degradation, poverty, social inequalities and weak governance. Given its complexity, effective flood risk management requires a better understanding of its conceptual context and comprehensive assessments that beyond hazard consider exposure, vulnerability and capacity. The study proposes a GIS-based Multi-Criteria Decision Analysis (MCDA) framework for assessing and mapping flood risk in the Thermi Basin in northern Greece, which is characterized by significant urban expansion, different land use/ land cover, dense hydrographic network, varied topography and seasonal precipitation events. The methodology analyzes seventeen parameters representing flood hazard, exposure and vulnerability/ capacity components. Parameter weighting is applied using the Analytic Hierarchy Process (AHP) based on expert judgments while Weighted Overlay Analysis is performed in GIS to create the flood risk map. The results indicate that 8,26% (503ha) of the study area is classified as low flood risk, 83,94% (5114ha) as moderate flood risk and 7,80% (476ha) as high flood risk. Impact analysis highlights varying potential impacts on the environment, infrastructure and population and the validation against official Areas of Potential Significant Flood Risk (APSFR) and 18 flood-prone locations generally confirms the plausibility of the model’s results. Finally, the framework proposes some indicative strategies for each flood risk zone that planners and decision-makers can further develop to support their mitigation efforts.