Analysis and evaluation of water quality characteristics in Olympic Dragon-shaped Water System in Beijing

The water quality was monthly monitored in the dragon-shaped water system in Beijing Olympic Park in 2012,and the water eutrophication and state were evaluated by trophic level index( TLI) method and water quality index( WQI) method. Some water quality indices including chemical oxygen demand( COD) Mn,biological oxygen demand( BOD 5),suspended solid( SS),Chl-a,total nitrogen( TN) and total phosphorus( TP) were found to be fluctuated sharply with time in the slightly alkaline,and supersaturated dissolved oxygen water in the dragonshaped water system. The relatively low level of TP in the water was the limiting factor of eutrophication in the dragon-shaped water system. The eutrophication was found to be changed from light eutrophication in spring to mesotrophication in summer and autumn,class Ⅲ water quality standard in most of the time to meet the water environment function target requirements. There was better water quality in submerged plant area than that in non- submerged plant area. The water quality was also affected by the drainage channel design. The findings provide a theoretical basis for water environmental protection of Beijing Olympic dragon-shaped water system.