Assessing and mapping flood hazard, vulnerability and risk in the Upper Brahmaputra River valley using stakeholders' knowledge and multicriteria evaluation (MCE)

Assessing flood hazard, vulnerability and integrated risk has long been recognised as an important input for the formulation of policies aiming at flood risk management. This investigation is an endeavour to assess hazard, vulnerability and risk due to flooding, using an indicator-based methodology incorporating stakeholders' knowledge and multicriteria evaluation in geographic information system (GIS) to achieve community-based assessment. The framework developed in this work is illustrated for the district of Dhemaji, a chronically flood-affected area in the Upper Brahmaputra River valley. Results show spatial distribution of hotspots of flood hazard and vulnerability and locations at risk at regional and subregional level. The emerged risk pattern indicates that vulnerability indicators are more significant contributors than hazard indicators while calculating risk for the Upper Brahmaputra River valley. The methodology provides a dynamic platform where the flexibility in uses of hazard and vulnerability indicators, depending on variation in physical and socioeconomic setup, is possible.