A GIS-Based Approach in Drainage and Morphometric Analysis of Suvarnavathi River Basin and Sub-watersheds,Karnataka,India

The present case study describes the morphometric analysis and its influence on the hydrology of the Suvarnavathi river basin and its sub-watersheds. ALOS DEM is used to extract slope and drainage layers while GIS software is used in the evaluation of linear, areal and relief aspects of morphometric parameters for 13 sub-watersheds of the entire river catchment area. The dendritic drainage pattern of the basin reveals moderate slopes while sub-parallel pattern shows high relief and structural control, especially along the 7th order trunk river of the basin. The circularity ratio, elongation ratio and form factor represent that the elongated study area is in the youth stage of basin development. Sub-watersheds belonging to high relief and slope show high bifurcation ratio and drainage density indicating areas under structural control. Whereas variation in values indicate the difference in topography. Stream frequency of all sub-watersheds shows a positive correlation with drainage density due to the hard rock lithological structures which reveals that the surface area has moderate permeability and groundwater potential is meagre. These studies are useful to mark the groundwater potential zone and artificial recharge area and plan for watershed management.