Correlation Analysis in Study of Relationship between ¹⁸O and Water Quality Indexes

Abstract

At the background of water diversion project from the Yangtze River to Taihu Lake, the experiment of diverting water from Taipu River was implemented from March 22 to April 7 in 2006. Synchronous isotope monitoring as well as water quantity and water quality is carried out. Combining water quality index and isotope abundance data, a grey correlation analysis has been made between six major water quality indexes and δ ¹⁸O values during sluice-supply water period, the pump-supply water period and the whole diverting period. Correlation degrees of the whole diverting water period are higher than that of the two different diverting water period for the reason that data of normal diverting water period which from April 5 to 7 is included in calculating correlation degrees during the whole diverting period. Meanwhile, all the correlation degrees except TP during the sluice-supply water period are higher than that during the pump-supply water period. It shows that pump-supply water had more obvious influence to the correlation degrees for the reason that there are more releasing water during pump-supply water period than sluice-supply water period. Furthermore, correlation degrees of the three branches upper Huangpu River are also calculated respectively. The results show that the correlation degrees of Xiaziwei and Sanjiaodu have the similar chang trend except the correlation degrees of NH₃-N and TN because of the supply of Taipu River and the river network around to the north branch Xietang and the middle branch Yuanxiejing. At last, it comes to the conclusion that diverting water from Taipu River have great improvement to the water environment of upper Huangpu River. And ¹⁸O as well as water quantity have a significant correlation with water quality.