Abstract:

The water quality in Chishui River was assessed by using the PCA method in the “7th 5year Plan” period and “11th 5year Plan” period.The results showed that the water quality of trunk stream is still very well.The central town was planned and developed for many years,there is a welldesingn urban infrastructure,and the urban sewage and brewery waste water were treated before discharge standard.so the water quality of W5 section has become better.Waterquality index of other sections has some changes.The source of tributary has to be controlled for that pollution factors become more and more.Overall,the water quality of trunk stream is still very well，but measurements should be taken to prevent water quality of tributary becoming worsen.