## 4 Conclusions and Discussion  
This paper applied a geographical fuzzy decision making methodology to identify the high-risk areas of flood risks in terms of multiple potential factors and experts' opinions. An integrated fuzzy AHP-TOPSIS and GIS allowed connecting decision makers with the factors influencing the floods. The systematic and logical approach allowed dealing with complicated multi-stakeholder and multi-criteria decision issues by site-specific weighting of the factors that affect the likelihood of floods. The model determines the normalized rating weight value, and the distance from the alternatives to the positive and negative ideal points. Determining the intensity of the influencing factors and the different sites in which the affected hamlets are at risk is vitally important. The findings of this study provide evidence on the direct impacts of increasingly devastating floods and suggest the required policies for the development of adaptation and prevention measures  
Figure 7: Map of the flood hazards zoning in the Phuoc Thang commune. for the local populations. Three critical problems in flood hazard assessment were considered in this study: drivers of flood hazards [38], affected areas [39], and zoning flood hazardous areas [40]. A hybrid approach using a GIS-based fuzzy AHP-TOPSIS was developed to solve these problems. 1. Results of the fuzzy AHP show that terrain elevation and creek-bottom terrain are the most important drivers, followed by stream density, drainage channel density, water storage, soil type, slope, and land use or land cover. The topography of the studied areas is most important: the closer to the main river, the lower the terrain. Water flows from higher to lower elevations and, therefore, the terrain influences the surface overflow and the penetration. Flat regions at lower elevation potentially submerge faster than higher regions. Land use and land cover is least impacted. Most of the communal areas are agricultural land or built-up sites; therefore, their functions are not affected. 2. Results of the fuzzy TOPSIS show that the hamlets of An Loi, Lac Dien, Luong Binh, and Pho Dong are the worst alternative sites. Because they are nearest to the negative ideal solution, it is necessary to pay more attention to flood hazards in these alternatives. 3. Results of a sensitivity analysis show that the most important role of land-induced criteria such as slope, terrain elevation, creek-bottom terrain, and soil type, is in estimating spatial distributions of flood hazard risks. This finding implies that for the Phuoc Thang commune, particularly, and other coastal plains, generally, removing one or a few water-induced (stream density, drainage channel density, and distance to water body) and anthropogenic-induced (high tide-induced flooding area, land use land cover, and water storage by transportation corridors) factors would not significantly affect the final risk distributions of the flood hazards. 4. Results of zoning flood hazardous areas based on the GIS show that hamlets near the Dai An River are flood-prone. The An Loi and Lac Dien hamlets either share their flat terrain or position close to the Dai An River, which determines their exposure to floods. In this study, the results of modeling are well explained using both available spatial and nonspatial data, such as field trip studies, FGDs with the involvement of local authorities, semi-structural questionnaires completed by village heads, thematic maps, documents, and official reports provided from official sources. Drivers challenging floods along the coast of Phuoc Thang, located in the lower Kon River basin, should be considered at a regional scale and include tropical storms, regional land use land cover change, and urbanization. The Kon River basin is affected by tropical storms which cause rains and floods. During the storms, the intensity of the rain is very high [25; 26; 27; 31]. Regional land use and land cover changes also contribute to local floods.