Drainage morphometry and its influence on hydrology in an semi arid region: using SRTM data and GIS

Abstract

An attempt has been made to study drainage morphometry and its influence on hydrology of Peddavanka watershed, South India. Drainage networks for the sub-basins were derived from topographical map (1:50,000) and Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM) data used for preparing elevation, slope and aspects maps. Geographical information system (GIS) was used in evaluation of linear, areal and relief aspects of morphometric parameters. The study reveals that SRTM DEM and GIS-based approach in evaluation of drainage morphometric parameters and their influence on hydrological characteristics at watershed level is more appropriate than the conventional methods. The mean Bifurcation ratio (R (b)) of the entire basin is 3.88 which indicate that the drainage pattern is not much influenced by geological structures. VIII sub-basin have high elongation ratio (R (e)), basin relief (B (h)), Ruggedness number (Rn) and time of concentration (T (c)). It indicates that the erosion and peak discharges are high in these basins. Therefore, the construction of the check dams and earth dams will help in reducing peak discharge on the main channel. These studies are very useful for implementing rainwater harvesting and watershed management.