GIS based drainage morphometry and its influence on hydrology in parts of Western Ghats region, Maharashtra, India

Abstract

Various drainage morphometric parameters in the Upper Bhima river basin and its influence on hydrological processes (e.g. runoff, peak flow, time to peak, infiltration, overland flow, etc.) were discussed using geographical information system (GIS) and remote sensing techniques. Survey of India topographical maps and ASTER digital elevation model was incorporated for thematic database generation and morphometric parameter evaluation in GIS environment. The whole study basin was divided into 8 sub-basins so that the spatial variation of morphological parameters and its influence on hydrology could be analyzed. The interrelationship between morphometric variables were computed (p < 0.05) and presented in a correlation matrix. The study revealed that mean basin slope (), drainage density (), length of overland flow () and basin relief () are closely associated and significantly related with a large number of morphometric variables. Due to close proximity of Western Ghats, sub-basins 1, 2, 4, 5 and 6 are highly influenced by slope, as a result, length of overland flow decreases and water immediately follows channel path. In contrast, sub-basins 3, 7 and 8 are relatively flatter, overland flow is relatively longer and favourable for infiltration. This study emphasizes on qualitative description about the hydrological variables influenced by the morphometric parameters in a mountainous basin in western India. Independent morphometric variables were identified from correlation matrix and used in a multiple criteria analysis (MCA) framework for watershed prioritization. Analytical hierarchical process, a MCA technique, identified the highest (sub-basin 4) and lowest (sub-basin 7) priority sub-basins in the Upper Bhima basin. The outcome of the study may be useful for watershed managers and planners while implementing soil and water conservation measures in the region.