MORPHOMETRIC ANAYSIS OF THE MAJOR VALLEY SYSTEMS AROUND BENGALURU

The three major Valley systems of Bengaluru namely Vrishabhavathi Valley, Hebbal Valley and Kormangala-Challaghatta Valley houses many lakes and play a very important role in its hydrological processes. The morphometric analysis helps us to learn about the characteristics of the underlying rock type, pervious nature of soil, slope gradients, runoff behavior and water retention potential within the Valley systems. Morphometric analysis was carried out for Linear, areal and relief aspects. The Survey of India topographical maps and Digital Elevation Model data were used to prepare the base map and the drainage maps with the help of GIS software. The Strahler system of stream ranking was adopted. Among the three Valleys, Vrishabhavathi Valley is observed to be the largest Valley in terms of area and perimeter. Vrishabhavathi Valley basin has sixth order stream as the highest stream order where as the other two Valleys have fifth order stream as the highest order. The drainage pattern formed within the Valley systems was observed to be dendritic. The watershed shape factor showed that the Vrishabhavathi Valley is elongated in shape where as the K-C Valley and the Hebbal Valleys are less elongated in shape comparatively. The drainage density of the three Valleys revealed that they fall under coarse drainage density classification. The relief aspects of the three Valleys exhibit low reliefs indicating a flat surface. This helps in designing a sustainable management plan for the three major Valley systems in terms of their conservation and also ensure sustainable soil and water usage within the Valley systems.