Morphometric Evaluation and Sub Basin Analysis in Hanur Watershed, Kollegal Taluk, Chamarajanagar District, Karnataka, India, using Remote Sensing and GIS Techniques

Abstract

The study area covers 1026 sq km comprising of 15 sub-watersheds, namely Saggiyam (SB-1), Mudoldoddi (SB-2), Halgapuram (SB-3), Deverabetta (SB-4), Mattugaudanadoddi (SB-5), Handgalli (SB-6), Manchepura (SB-7), Lokkanahalli (SB-8), Chinchalli (SB-9), Prakash palya (SB-10), Naripura (SB-11), Adugulpodu (SB-12), Ramayanadoddi (SB-13), Jodukara hatti (SB-14), Depudisahibradoddi (SB-15) which range in area from 16.87 to 180.02 sq km. Different morphometric parameters were evaluated to understand the drainage characteristics. The drainage pattern of these sub basins have been delineated using Geocoded FCC bands 2, 3 and 4, of IRS 1C and 1D (LISS 111+ PAN merged) on 1:50,000 scale and Survey of India Toposheets as reference. The morphometric parameters are computed using Arc Info and Arc View GIS software’s. The drainage pattern of the study has shown dendritic to sub-dendritic drainage pattern with stream orders ranging from 4th to 5th order. The Drainage density ranges from 1.51 to 4.83 km/km² suggesting coarse to moderate drainage texture. The change in values of stream length ratio indicates their late youth stage of geomorphic development. The values of bifurcation ratio are ranging from 0.11 to 20.75 indicating that the study area is having strong structural control over the drainage pattern and all the sub basins fall under normal basin category. The values of form factor and circulatory ratio, suggest that the sub basins are elongated to circular in shape. Geographic Information System, when used with satellite images, could help in determining the morphometric parameters of watershed and river basins. It is concluded that remote sensing ground and GIS have been proved to be efficient tools in drainage delineation and updation.