A GIS-Based Multi-Criteria Decision Analysis for Land Subsidence Susceptibility Mapping and Risk Assessment of Water and Wastewater Networks in Tabriz City

Abstract. Land subsidence in contemporary megacities, driven by the overexploitation of groundwater resources, is akin to a silent bomb on the verge of detonation. It poses the potential for irreversible disasters affecting urban infrastructure, buildings, and the lives of thousands of people. This creeping phenomenon directly threatens the security, economy, and health of city residents with increasing severity. The metropolis of Tabriz has likewise experienced a growing trend of land subsidence over recent decades, and the present study investigates the spatial potential of subsidence across its urban extent. To this end, an integrated GIS–MCDA approach, combined with remote sensing data, was employed. Specifically, environmental layers influencing subsidence risk were first weighted and integrated using the WLC multi-criteria technique. Subsequently, the resulting hazard zoning map was validated against COSMO-SkyMed satellite imagery. According to the findings, the adopted methodology produced accurate results, with 93.3% of high-risk zones overlapping with areas of actual subsidence in the region. The outcomes of this research underscore the critical importance of addressing land subsidence hazards within the study area and demonstrate that the application of an integrated RS–GIS approach can provide a comprehensive and reliable model for decision-makers and urban planners in managing environmental risks.