Causes and Consequences of Channel Changes – A Spatio-Temporal Analysis Using Remote Sensing and Gis— Jaldhaka-Diana River System (Lower Course),

Abstract

Channel changes with respect to time and space play a significant role in stream flow dynamics. The rambling and trailing of  channels in the studied region has been studied  through systematic analysis and interpretation of diverse channel configuration and multi-channel orientation using multi-temporal Topographical maps and Satellite images for a period spanning nearly 80 years (1930–2011). For this specific purpose lower course of Diana River in the Jaldhaka-Diana river system has been selected in the Duars region of the Jalpaiguri district, West Bengal which is virtually a zone of transition between the Himalayan Mountains and the North Bengal plain.  The prime objective of the study is to reveal the spatio-temporal sequences of channel changes, consequent movement of confluence point and the factors and causes of such movement. For this particular extraction, Base map has been generated with the help of SOI Topographical maps and satellite images of the respective area. For this purpose updated version of ERDAS Imaging is employed as image processing tool for enhancing, merging and to update the spatial information of channel configuration and Arc GIS for final product generation. Following the specific objective of the study it has been deduced that during this span the confluence point has moved and re-oriented both upstream and downstream on a historical time scale and new confluence points have been created by repeated shifting and migration of channels. No definite trend is observed in the movement of the confluence points. However, but it is noticed that some distinct flow dynamics and channel maintaining processes are actively performing in this spatio-temporal analysis of channel changes.

Keywords: Morphogenetic complex, Multi-channel system, Confluence Dynamics, Channel avulsion, Channel shifting, Erosion-accretion process