This chapter investigates the Ngawun River Basin (Ayeyarwady Region), which is prone to flooding due to its geomorphic features and geographic location in the path of cyclonic storms. The research identifies three distinct morphological zones within the basin, each influenced by varying hydrodynamic conditions. In the upper reaches, the “fluvial dominated zone” features sedimentary structures formed by riverine processes characterized by medium to coarse sand and moderate meandering. The middle section, the “tidal and fluvial transitional zone,” exhibits a dynamic interplay between fluvial and tidal forces with fine sand, silt, and mud. The tidal dominated zone’s lower part is primarily shaped by tidal processes, characterized by rhythmically laminated muds and minimal bioturbation. Natural hillocks in Pathein and Myaungmya act as barriers against flooding. However, man-made structures, including embankments and highways, while upgraded to mitigate flood risks, impede the overflow of the Ngawun River during high-flow seasons, making Thabaung Township vulnerable to prolonged flooding. Thabaung, in a transitional zone, experiences both fluvial and tidal effects, resulting in extensive floodplain conditions. The southern part of the basin, predominantly flat, is significantly influenced by tidal effects, while the western part, characterized by piedmont and hilly terrain, is less susceptible to riverine flood hazards. Using GIS, RS, and Analytical Hierarchy Process (AHP), it presents a robust framework for assessing flood hazards. The flood hazard map classifies areas into five levels: very high, high, moderate, low, and very low. Regions with very high and high Flood Hazard Index (FHI) are vulnerable due to their proximity to the active river channel and floodplain, compounded by a low slope.