Brahmani River Basin of eastern Odisha, India, has frequently seen flash floods over the past three decades despite being located near semi-arid/arid regions. However, in situations where there is a dearth of flood-related data, identifying a basin’s flood risk zone is crucial. Therefore, the research sought to assess the watershed’s flood risks and high-risk zones using Multi-Criteria Decision-Analysis (MCDA) and Geographical Information System (GIS). For this approach, the present study proposed the MCDA theory to list the five primary criteria that were taken into account while utilizing a spatial database to locate areas at risk of flooding, consisting of agents such as, number of households (NH), population (P), literacy (L), land use (LU), and infrastructure vulnerabilities (IV). Meanwhile, population, flood hazard zone and land use were given careful consideration when mapping this watershed’s flood risk area. A weighted overlay analysis tool has been applied to the integration of the thematic layers in order to determine the zones of flood risk and hazard. The outcomes of the geospatial method were contrasted with the results derived from MCDA theory. Based on the observation, the results showed that this theory can also accurately and precisely define a basin’s flood danger zone. In this chapter, around 1850 villages corresponds to high infrastructural vulnerability zones, whereas 75 villages is observed to have a moderate-high social vulnerability zone. About 48 villages of the study area, consisting of villages, where agriculture is observed to have a primary source of subsistence, that exhibits high vulnerability zones. These results underline the necessity of regularly and sustainably implementing flood prediction, early warning systems, and efficient management techniques.