Characteristics of Water Quality Changes during 2014—2018 in Panlong River of Dianchi Lake

In December,2013,Niulan River diversion entered Dianchi Lake through Panlong River,as the water channel for Niulan River diversion project to Dianchi Lake.The change of environmental quality of Panlong River would be the best response to the water purification effect of the diversion project.The results showed that the water quality of Panlong River was relatively stable from 2014 to 2018.TN,TP and NH₃-N were no significant downward trend.However,the concentration values in rainy season were higher than that in dry season.Compared with that before Niulan River diversion project（2013）,the concentration of TN,TP and NH₃-N decreased by 50%-70%,but TN was still inferior to Class Ⅴ.Although TP met Class Ⅲ water standard for river,it still did not meet Class Ⅲ water standard for lake.Therefore,TN and TP were the main factors affecting the water quality of Panlong River.