Multivariate Statistical Techniques for the Evaluation of Water Quality: A Case Study in Shitoukoumen Reservoir Catchment

Multivariate statistical approach was used to investigate the dominant factors that influence the water quality deterioration of Shitoukoumen Reservoir in Changchun City, China and comprehensively evaluated its water quality. According to the data generated during 2001-2007, with monitoring at four different sites, cluster analysis (CA) and factor analysis (FA) were applied to identify the possible factors or/and sources that influenced surface water quality. Results show that: three factors were extracted through factor analysis. Factorl was dominated by DO, Ammonical nitrogen, TN, COD_Mn, COD, BOD₅; factor 2 was TP; factor 3 included fluoride and total coliforms. Comprehensive evaluation results showed the water quality of Shitoukoumen reservoir belongs to Grade III and the main pollutant is TP. The water quality of Yinma River and Chalu River belong to Grade III which are mainly influenced by factor 1. The average quality of Shuangyang River belongs to Grade V and the pollutants may result from factor 1 and factor 2. The water quality deterioration of Shitoukoumen catchment is mainly resulting from the non-point source pollution and domestic wastewater. This study indicates the necessity and usefulness of multivariate statistical techniques for evaluation and interpretation of the data with a view to get better information about the water quality and design some remedial techniques to ensure the safety of drinking water in Changchun.