Application of analytical hierarchy process (AHP) for flood risk assessment: a case study in Malda district of West Bengal, India

Flood, a perennial phenomenon mainly in low lying deltaic areas and flood plain regions, can be viewed as beneficial for enhancing soil fertility and agricultural production, but also as one of the most destructive natural hazard endangering human life, property, economy and environment. Floods in lower Gangatic flood plain are annual event, especially Malda district of West Bengal has been severely affected by flood over the years by the mighty Ganga and its left bank tributaries during high stage of flow. Assessing risk from flood using composite hazard and vulnerability index has been a widely recognized tool which acts as an important element for formulation of policies aiming at flood risk reduction. The present investigation is an endeavor to assess risk due to flooding using analytical hierarchical processes incorporating flood hazard elements and vulnerability indicators in geographical information system environment. Flood hazard map has been prepared using selected morphological and hydrometerological elements whereas the vulnerability map has been produced using demographic, socio-economic and infrastructural elements. Finally, risk map of flood has been developed compiling both the above-mentioned aspects. The analysis concluded that the northern and western parts of the district are most risk prone from flood hazard than the eastern part.