Decision Support Tool for Colombo Canal System Water Quality Monitoring

Abstract

Pollution of the Colombo Canal System, which is a complex network of open canals and marshes catering to the storm drainage needs of Greater Colombo, has been recognized as a major environmental issue. A Water Quality Monitoring Program is being carried out by SLLR&DC since 1997, where monthly measurements are recorded at 20 locations for 10 parameters. An attempt was made to integrate the raw data, an analysis of the water quality regime of each location, and a study of its relationship with canal water level and average monthly rainfall, by developing a simple, user- friendly computer package called the Water Quality Monitor (WQM). It will assist the user in decision- making, regarding the attainable level of quality for a particular site, and whether that quality level could be reached by varying the canal water level. It also provides a general idea on how much of the target quality is attainable with the dilution and flushing effect of rainfall. A special feature of WQM is the facility provided to analyse the user's own data sets, apart from the built-in Colombo data. This paper describes the rationale, methodology of development and the application of the software package of the 'Water Quality Monitor'.