Comparative Analysis of Flood Risk Zoning and Susceptibility Assessment for the Western Corn Belt Plains using Geospatial Techniques

Flooding is among the most destructive natural hazards, causing severe socioeconomic and environmental impacts. Accurate flood susceptibility assessment is critical for effective mitigation and sustainable resource planning. This study integrates Geographic Information Systems (GIS), Remote Sensing (RS), and multi-criteria decision-making (MCDM) methods to evaluate flood vulnerability across four Iowa sub-basins: Middle Cedar, Lower Cedar, Middle Iowa, and Lower Iowa. Three approaches—Analytic Hierarchy Process (AHP), Fuzzy AHP (FAHP), and Equal Weighting (EW)—were applied to compare the influence of geophysical and socioeconomic factors. Key parameters included elevation, slope, land use/land cover (LULC), soil type, precipitation, river proximity, and low-income households. High-resolution (30-meter) datasets from SRTM DEM, Landsat-8, and TRMM precipitation sources were processed to develop composite flood susceptibility indices within a GIS framework. Results reveal significant spatial variability, with high-risk zones concentrated in low-lying areas near major rivers and socioeconomically vulnerable urban regions. The Middle Cedar sub-basin exhibited the highest susceptibility, while Lower Cedar and Middle Iowa showed lower risk levels. FAHP demonstrated greater sensitivity in capturing risk variations compared to AHP and EW models. The findings underscore the importance of integrating physical and socioeconomic factors into flood assessments. They also highlight the need for targeted interventions, such as enhancing drainage infrastructure, equitable resource distribution, and supporting vulnerable populations. This study delivers a robust, scalable approach for flood susceptibility mapping, offering valuable insights for policymakers, urban planners, and disaster management authorities to enhance community resilience and guide flood mitigation strategies in Iowa and similarly flood-prone regions.