RELATIONSHIP BETWEEN GEOMORPHIC SURFACES AND NATURAL HAZARDS IN THE KALU GANGA BASIN

Abstract

The concept of geomorphic surfaces can be applied to the study of macro- and micro-landform formation, their formative processes and evolution. It indicates the erosional or depositional surfaces in a “available relief". The Kalu Ganga, the focus of this study, is the second largest river basin in Sri Lanka, with an approximate area of 2,688 km? and a mean flow of 280 m/sec. The average annual rainfall in the basin is 11,303 million m?, of which 8,184 million m? is lost as runoff. Based on altitude (between ms] and 1,830 m), as well as relief and drainage orders, seven geomorphic surfaces can be recognized in the Kalu Ganga basin.