Network-based GIS modeling for flood evacuation route plan in Saghata Upazila, Bangladesh

Bangladesh is highly susceptible to recurrent and devastating floods due to its geographic location. This research investigates the application of Geographic Information Systems (GIS) in developing flood evacuation route plans based on available spatial data at the local scale with a case study in Saghata Upazila, Gaibandha District. The study integrates spatial analyses, Analytical Hierarchy Process (AHP) as a multi-criteria decision-making technique, and weighted overlay to generate flood vulnerability maps based on key conditioning factors: elevation, slope, drainage density, rainfall, proximity to rivers, and land use. Road network analysis using Dijkstra's algorithm further identifies optimal evacuation routes to available flood shelter and administrative centers accounting for both shortest distance and travel time. Findings reveal that eastern Saghata is the most flood-prone area due to its low elevation and proximity to the river. Also, critical infrastructures are often spatially mismatched with high-density populations. This study is intended as a planning-level GIS-based framework developed under data-limited conditions. The research demonstrates how GIS can inform resilient evacuation planning with limited local-scale spatial data, highlighting the need for construction and decentralized shelter distribution, the availability of diverse local-scale spatial datasets, and real-time spatial data integration. The study contributes to disaster risk reduction by providing actionable spatial insights for local policymakers, emergency responders, and planners.