Quantitative and qualitative study of the Tawi basin: Inferences from Digital Elevation Model (DEM) using geospatial technology

Abstract

The quantitative and qualitative analysis of the basin is fundamental to understand the structural and hydrological control of the basin. In the present study morphometric and morph tectonic parameters of the Tawi basin has been analyzed to infer the geological variation, topographic information, structural and complex tectonic behavior at a watershed scale. The assessment of several of drainage network and their relative parameters has been quantified by using the Digital Elevation Model (DEM) based analysis in the Geographic Information System (GIS) environment. Based on the quantitative analysis in terms of linear, aerial and relief it is well understood that the basin is inhomogeneous in nature, less structurally stable, very gentle to steep slopes, compounded by aggradational and denudational processes in large scale, exhibited by incompetent rocks and a portion of the basin is prone to flood particularly in the lower reaches. The quantified results show that in the various watersheds of the Tawi basin bifurcation ratio (Rb) varies from 0.001 to 6.80 and the mean bifurcation ratio (Rbm) varies from 2.58 to 4.11. The mean stream length (Lsm) in the various watersheds of Tawi basin varies from 0.019 to 60.26 km. The drainage density (Dd) of Tawi basin varies from 0 to 9.63 km/km2, and the value of the drainage texture (Td) varies from 3.76 to 13.38 km-1. The qualitative analysis based on the asymmetric factor (AF) of the Tawi basin shows that the watersheds W5 and W6 are moderately asymmetric, and W2 and W4 as strongly asymmetric in nature, whereas the hypsometric integral (HI) values reveal that watershed W1 is the most stable watershed with a highest HI value of 0.89, while the W7 is the least stable with a HI value of 0.28, providing a comprehensive understanding of the geomorphic dynamics in the Tawi basin.