River erosion and degradation of Maha Oya river basin: a study based on selected areas

Abstract

Water is the unique resource among the natural resources that causes to different kind of changes in time and space. As an island nation, Sri Lanka has number of sources its water capacity. Among those sources, Maha Oya is one of a major river basin in Sri Lanka. It consists of the catchment area of 1528 km2 and the extent of drainage is 1.6 km. The main purpose of this study is to find the river erosion and degradation in Maha Oya river basin. Primary and secondary data were used for analysis. The data were used to identify the erosion and degradation during 1991, 2001 and 2014. Spatial and attribute analysis were undertaken using GIS 10.1 and MS Office application. High degradation, moderate degradation and low degradation for the selected regions were analysed in GIS environment. The study revealed that the erosion was increased from 1991 to 2014. The erosion rate (19.77%) in 1991 increased to 43.41% in 2014 that was indicated such a higher erosion and degradation of this area. In order to flooding, soil digging, soil erosion, over consumption of water and the environmental impacts are to be controlled using proper management practices (reduce the river erosion and degradation).