V. CASE STUDY: MANAGEMENT AND CONSERVATION OF FRESHWATER RESOURCES IN KUALA LUMPUR
C. Protection of water quality and habitats
7. Water quality assessment
Water quality assessment is generally conducted in terms of the physical, chemical and biological characteristics of a water body. Two types of measurements are carried out, i.e., in situ and laboratory analyses. In situ water quality measurements include parameters such as turbidity, salinity, temperature, pH, dissolved oxygen and electrical conductivity, while a laboratory analysis is performed for as many as 30 other chemical and biological parameters that include bacteriological indicators, and pesticide and detergent levels.
The appraisal of water quality in Kuala Lumpur is based on the water quality index (WQI), which is the most commonly used index to denote the quality of river water. As with similar systems, WQI relates a group of water quality parameters, i.e., biochemical oxygen demand, chemical oxygen demand, ammoniacal nitrogen, suspended solids and pH, to a common scale and combines them into a single number in accordance with a chosen method or model of computation. The main objective of the WQI system is to provide a preliminary means of assessing a water body for compliance with the standards adopted for five designated classes of beneficial uses. The study extended WQI to the assessment of water quality trends for management purposes, even though it is not specifically intended to be an absolute measure of the degree of pollution or actual water quality.