Geospatial-based tectono-morphometric analyses of the drainage system in the Chengi and Myinee River basins in the Chittagong Hill Tracts, Bangladesh

Neotectonics is a major factor for controlling landform development in tectonically active Chittagong Tripura Fold Belt (CTFB) region, along the western flank of the Indo-Burma ranges. Morphotectonic parameters are excellent indicators for landscape morphology evaluation to highlight past and ongoing tectonic processes in a region. To investigate the matter, different morphometric indices such as linear, areal, and relief parameters were quantified using the Digital Elevation Model (DEM) data and its attributes of Chengi River Basin (CRB) and Myinee River Basin (MRB) in CTBF. All the computations for morphometric characteristics and visualization were performed in the Geographical Information System (GIS) and statistical platforms. The CRB and MRB are identified as fifth and fourth-order basins with a total area of 503.53 km² and 267.28 km², respectively which have low drainage frequency. The Bifurcation ratio (Rb) value of both these basins is indicative of structural control. TSI controls the upper course of the rivers and the variations have been observed in year-wise Topographic Sinuosity Index (TSI) distribution. The Asymmetry Factor (AF) in both these basins indicates that CRB is tilting towards the western side, whereas the MRB is tilting towards the eastern side. Moreover, these two rivers are elongated in nature indicates tectonic activity along with Google earth (GE) seamless mosaic image-based longitudinal profiles indicates significant deformation along their courses. In addition, the moderate Hypsometric Integral (HI) value shows a convex shape in the lower portion, which might be related to the upliftment along a fault or perhaps an upliftment associated with recent folding. The overall results in both these basins indicate the presence of tectonic activity. Therefore, morphotectonic analyses using DEM, Landsat satellite data, and GE seamless data are found useful in this study and could be considered an ideal tool for any complex basin morphotectonic study.