Assessment of spatial variation in water quality: a case study at Moragoda Ela, Galle

Abstract

In this study the water quality of Moragoda Ela located in the Galle town was analyzed using graphical and statistical analysis of the water quality data at 14 sampling points along the stream. Mean values of COD and BOD5 were 127.5mg/L and 14.8 mg/L, respectively. Mean values of fecal and total coliforms were 47 and 23471 colonies/100 mL, respectively. BOD5, COD and the total coliform content exceeded the ambient water quality standards for inland waters in Sri Lanka. The mean fecal coliform value did not satisfy the ambient standards of fecal coliform content for the activities other than irrigations and agricultural needs. Overall the water quality was lower than the demanded quality of water for many activities. The study revealed that the water quality deterioration was attributed to the illegal discharges from a large number of industries, institutions and commercial establishments, high population density and illegal community activities.