Morphometric aspects of a small tropical mountain river system, the southern Western Ghats, India

Abstract

Abstract The Muthirapuzha watershed (MW) is one among the major tributaries of Periyar – the longest west flowing river in Kerala, India. A morphometric analysis was carried out to determine the spatial variations in the drainage characteristics of MW and its 14 fourth order sub-watersheds (SW1–SW14) using Survey of India topographic maps and Landsat ETM+ imagery. The study revealed that the watershed includes a sixth order stream and lower order streams dominate the basin. Results did indicate that rainfall has a significant role in the drainage development whereas structure and relief of rocks dictate the drainage pattern. The asymmetry in the drainage distribution is correlated with the tectonic history of the Munnar plateau in the late Paleocene age. The watershed is moderate to well-drained and exhibited a geomorphic maturity in its physiographic development. The shape parameters revealed the elongated nature of MW and drainage network development in the watershed. Further, the analysis provided significant insight into the terrain characteristics. This study strongly brings to light, (a) the tendency of the watershed to soil loss and (b) the hydrological makeup of the sub-watersheds, which combined helped to formulate a comprehensive watershed management plan.