Comparing Flood Susceptibility Mapping with Flood Disaster Periods: A Case Study of the Dari-Ekh Area, Bayanzurkh District

Abstract

This study integrates Geographic Information Systems (GIS) with Multi-Criteria Evaluation (MCE) methods to develop a flood susceptibility map for the Dar-Ekh area of Bayanzurkh District, Ulaanbaatar city, and validates the model spatially by comparing it against the actual flood inundation extent recorded in 2023. Eight conditioning factors were incorporated into the analysis: elevation, slope, precipitation, distance from rivers, distance from roads, land use/land cover, soil type, and drainage density. Factor weights were determined using the Analytic Hierarchy Process (AHP), and a flood risk map was subsequently produced through Weighted Overlay Analysis. The results indicate that, of the total study area of 1,435.4 hectares, 35.9% falls within high to very high flood risk zones, 43.7% within moderate risk zones, and the remainder within low to very low risk categories. Of the 4,733 land parcels assessed, 62.6% are situated within flood-prone zones. Critically, 99.2% of the 764 land parcels affected by the documented 2023 flood event coincided with the high-risk zones delineated by the susceptibility model, confirming the accuracy and reliability of the proposed approach. Comparative analysis further identified precipitation (27%) and distance from rivers (23%) as the two most influential factors contributing to flood risk in the study area. The findings of this study carry significant implications for urban planning, land use policy formulation, and the design of targeted flood risk mitigation measures.