Time series analysis of river water quality data from a tropical urban catchment

Abstract

Studies assessing long term changes of water quality have been recognized as a key tool for understanding ongoing processes in watersheds and for providing an essential background for evaluation of rapid changes within industrialized and populated urban areas. This study examines the trends of water quality parameters in the Pencala River in Kuala Lumpur from 1997 to 2009. The trend analysis was performed on thirteen physical and chemical parameters using the Mann-Kendall Seasonal test and the Sen’s Slope estimator. The statistical results indicated that most water quality parameters showed a downward trend for yearly average concentration. The Water Quality Index (WQI) for Pencala River was improved from Class V to Class IV, according to National Water Quality Standards for Malaysia. BOD, COD, NH3-N and SS showed decreasing trends during the study period. The improvements seen in river water quality appear to be the result of improved wastewater treatment at the study catchment. © 2016 Taylor & Francis Group, London.