Remote sensing and GIS-based analysis of evolving planform morphology of the middle-lower part of the Ganga River, India

Abstract

The present work addresses the planform dynamics of the Ganga River in the middle-lower portion over the last six decades and the evolution and transformation of the channel and its floodplain with the help of remote sensing and GIS techniques. The methodology of the study has been incorporated into topographic sheet and satellite image processing & mapping and geomorphic analysis. Three geomorphic technique have been incorporated here for the geomorphic analysis: braid-channel ratio, sinuosity index and water-bar covered area ratio. Findings of this study are: i) the channel has shifted considerably throughout the study reach especially in the up and downstream of Farakka Barrage, ii) Between 1978 and 1990 there was a significant decrease in the channel area due to the massive migration in the immediate downstream of Farakka, iii) Between 1978 and 1990 the bar covered area was less compared to a water covered area that indicates high sinuosity but in 2001 and 2014 the bar covered area exceeded the water covered area that reflects a high braid-channel ratio, v) The autogenic evolution of the channel and the active floodplain. Keywords: Remote sensing & GIS, Satellite images, Ganga River, Planform morphology, Floodplain evolution