8. Application of Remote Sensing and GIS in Understanding Channel Confluence Morphology of Barakar River in Western Most Fringe of Lower Ganga Basin

The channel confluences are the sensitive junctions that face significant hydraulic and morphological changes within the river system. Five major confluences of the Barakar River have been considered for the geomorphic investigation. The various data products, i.e. Topographical maps (1955), IRS LISS III Satellite Images (2011), Digital Elevation Data (ASTER DEM) (2011), and the Google Earth Map (2009–2015) have been used in this study. The study concerns the morphology of the confluences and the impacts of confluence angle, tributary length, tributary basin area and lithological controls on the confluences especially in the Quaternary period. There is no definite cause–effect relationship of confluence angle to scour depth and w/d ratio but has a positive relationship between w/d ratio of the post-confluence stream and the area of the tributary basin. The studied confluences are significantly controlled by the lithological influences and it almost defies other effective factors i.e. confluence angle, tributary length, etc.