Impact of Land Use on Water Quality of Kelani River

Abstract

Kelani River water is consumed by a considerable portion of the population of the country. This study experimentally derives relationship between land use and surface water quality of Kelani River for effective water management. Water quality of river within selected study area is examined for duration of six months and they are correlated with the land use data of watershed of the river. Study area is divided into two catchments based on their land uses. Analysis of land use data in two catchments revealed that there is a significant increment of urbanization in Lower Kelani ganga catchment whereas agricultural and forest areas were higher in the Lower middle Kelani ganga catchment. Nitrate, Phosphate, Turbidity, TDS, Temperature, Fecal coliform have been increased in urban dominated catchment. Higher level of DO (sat) and pH have been observed with the increment of the cultivated areas. Although the water quality parameters show significant variations with the impact of land use patterns, overall water quality classified as Water Quality Index (WQI) was higher among the sample stations of catchment 2 and lower among the sample station of catchment 1