Development of village-wise flood risk index map using multi-temporal satellite data: a study of Nagaon district, Assam, India
The Nagaon district in Assam is in a sub-humid region with a greater part of the district comprising alluvial soil ranging from pure sand on the banks of the Brahmaputra to stiff clay. The area is subjected to frequent flooding by rivers during a spell of 4 months in a year. In the present study, flood hazard layer is considered as the primary input and is integrated with land use/land cover, infrastructure and population data and weightages are assigned to each class. Based on this, village flood risk index map for Nagaon district has been generated. The results of analyses indicate that about 267 villages are in the moderate–high risk index zone. About 35,354 ha of the district is in high flood hazard zone and about 25,281 ha of crop area is affected annually. We conclude that use of multi-temporal satellite datasets, coupled with GIS tools, are useful in identifying vulnerability of infrastructure, population and land use in the event of flood disaster and in calculating the flood risk index.