Terrain Analysis Using GIS for Hydrological Applications

Abstract

The terrain of Bharathapuzha watershed has been analysed using (DTA) to derive various geomorphometric parameters which are of importance in hydrological applications. The DTA was conducted using different operations especially the DEM hydro-processing tool box of the Free and Open Source Software (FOSS) GIS software ILWIS. The Bharathapuzha river basin taken for the study was of an area of 3844.32 km2. The Digital Terrain Analysis of Bharathapuzha watershed resulted in the creation of slope map, aspect map, drainage density map, stream order map, longest flow length map, sub-catchments map, sub-watersheds of tributaries map etc. The morphometric parameters of Bharathapuzha river basin like Stream order (Nu), Mean stream length (Lsm), Stream length ratio (Rl), Mean bifurcation ratio (Rbm), Drainage density (Dd), Drainage texture (T), Stream frequency (Fs), Form factor (Ff), Length of overland flow (Lg), Relief (R), Relief ratio (Rr), Basin length, Sinuosity Index (SI) have been found. The slope of the basin varied from 0 to 70. The basin was found to be of elongated nature with moderate relief and slopes. The extracted drainage network was classified according to Strahler system of classification and it reveals that the terrain exhibits dendritic drainage pattern. The study area is well drained in nature with the stream order varying from 1 to 6. The basin is dominated by lower order streams and the total length of the stream is maximum is first order streams. The quantitative analysis of linear and relief parameters using GIS is found to be of immense utility in linear basin evolution, basin prioritization for soil and water conservation and natural resource management.