Quantitative Geomorphological Analysis to Infer the Hydrological Behaviour of Streams Draining into the Vembanad Lake – A Ramsar Site along the Southwest Coast of India

Abstract

Vembanad lake system (VLS) is a Ramsar wetland of premier importance along the south west coast of India. This system spread over 13098 km2 accounts for 33.7% of total geographic area of Kerala state. VLS sustains by the input of six main river systems of Kerala viz., Achankovil, Pampa, Manimala, Meenachil, Muvattupuzha and Periyar. Central focus of this study is to find out the influence of morphometric variables on hydrological processes using geo-informatics and correlation analysis and to analyse the scale dependence of basin hypsometry in steady state topography and hydrology. The study also examines the contribution of each river in making the entities of this wetland system by portraying the morphometric and hypsometric parameters of its watershed. The results of this analysis reveals that the Manimala river basin has survived with rapid denudation activities and run off mechanism, while Periyar and Pampa river basins have culminating stage of development and are tectonically active. This study immensely contributes to the knowledge on the influence of morphometric variables on hydrological process and scale dependence of basin hypsometry in steady state topography including hydrology of VLS. The results will shed some light on hydrologic makeup of inflow rivers and will be beneficial for the sustainable management of India’s one of the premier wetlands.