Geospatial approaches of TGSI and morphometric analysis in the Mahi River basin using Landsat 8 OLI/TIRS and SRTM-DEM.

Abstract

The research objective is to assess the Mahi River basin, morphometric parameters, and structurally controlled morphological terrains about the topsoil grain size index (TGSI), based on satellite data including Landsat 8 OLI/TIRS and SRTM-DEM data, using ArcGIS processing software. According to morphometric analysis, the Mahi River basin has an area of 28,844.2 km2 and is a drainage basin of the 8th order. In the sub-basin (SB8), bifurcation ratio reveals structural and geomorphological disorder, and high sinuosity causes significant meandering. These positive dependency factors, such as drainage density (Dd) and stream frequency (Sf), are increasing in SB7, SB8, SB12, and SB13, which results in high permeability, strong runoff, a flat topography, and a gentle slope. TGSI has been performed to analyze the geomorphological features of the structurally controlled Mahi River. The Landsat 8 OLI/TIRS has been utilized for the TGSI analysis, and SRTM-DEM has been utilized for the extraction of structurally controlled lineaments of the river basin. The resultant structurally controlled terrains have been cross-verified based on the DN reflectance of TGSI and the lineament type in the river basin for the morphometry. The results of the TGSI reveal that the minimum and maximum values are -0.1324 and 0.4207; the dominant type of terrain is pediment pediplain complex (PPC), having the TGSI range 0.1322 to 0.4207 with the fracture-type structural dominance with an area of 56.7% of the total area. The results reveal that the structural linear features in the Mahi catchment consist of structural deformed bodies such as faults, fractures, and ridge plains. Thus, it can be observed from the findings that remote sensing data (SRTM-DEM) combined with GIS methodology prove to be an effective tool in morphometric analysis and TGSI data could be utilized in the future for basin management and other hydrological studies.