Analyzing the Complex Interaction of Active Tectonics and Basin Scale Geomorphology: A Case Study of Chel River Basin Using GIS Tool

Abstract

The channel of Chel expressing a highly dynamic behavior in its entire course especially at the mountain out let by means of sediment-water supply variation. The existing water regime is the expression of highly variable nature of rainfall and structurally controlled river channel. Fluvial dynamics of Chel basin is highly abrupt in nature as the seasonal alterations disclose no steady trend of ongoing channel processes. Dependent on tectonic activity, hydrological regime, and sediment load of certain streams, the characteristics of the mountain front of the Darjeeling sub-Himalaya display a considerable variability. The surface is made up of a variety of alluvial fans from Quaternary sand deposition. The longitudinal profile following the channel thalweg shows distinct fluctuations of height due to such epierogenetic movements and interruption of normal cycle of erosion. The value of Hypsometric integral (48.56) indicates that the fluvial system is approaching to late youthful stage. The reason of tectonic instability and complex cycle of epierogenetic upliftments have been controlling the process of dynamic rejuvenation in this basin.