A Study on Channel Migration of the Subansiri River in Assam Using Remote Sensing and GIS Technology

The Subansiri is a major Trans Himalayan tributary of the River Brahmaputra, characterized by its extremely dynamic and unstable alluvial channel in Assam. In this study, the pattern of channel shifting as well as various other changes of the Subansiri river have been studied for the period from 1828 to 2011. Five different types of channel shift have been observed in the Subansiri river. They are (i) alternate barinduced shifting, (ii) neck cut-off, (iii) chute cut-off, (iv) meander shift and (v) avulsion or rapid diversion. The channel pattern of the Subansiri river in Assam changes continuously with large number of channels being abandoned and new channels developed in the course of a few years. Large discharge and heavy sediment load during floods cause the river to be extremely unstable, because of which it consistently migrates laterally from the eastern side to the western side of the basin abandoning the earlier channels.