Jinze Reservoir is the main drinking water source for southwest Shanghai. The water quality in the upstream Taipu River and reservoir have an important impact on the performance of the reservoir and the quality of the water supply. Conventional water parameters were analyzed using principal component analysis (PCA) to evaluate seasonal variations in water quality in the upper reaches of Jinze Reservoir. The parallel factor (PARAFAC) was also used to analyze water-soluble dissolved organic matter (FDOM) in the upstream waters and reservoir area. Furthermore, the relationships between water fluorescence intensity and conventional water quality indicators were analyzed using correlation analysis. The results show that water quality in the upper reaches of Jinze Reservoir is worst in the winter, and water quality gradually deteriorates in the outer sections of the reservoir due to external pollution inputs. Ecological purification within the reservoir area functions to improve water quality. The water body FDOM content is mainly composed of proteinoids and humus. Protein-like substances are the main components of this material, and each component exhibits clear spatial and temporal distribution characteristics. External pollution is the main factor affecting the total fluorescence intensity of the FDOM outside of the reservoir. In the reservoir, the ecological environment affects the total fluorescence intensity of FDOM. The total fluorescence intensity of FDOM showed an increasing downstream spatial trend, which was significantly correlated with NH4+-N, petroleum, TOC, chloride, and sulfate content in the water. By detecting the total fluorescence intensity of FDOM, the rapid analysis of water quality can be achieved to inform early warning.
Keywords: Jinze Reservoir; Taipu River; fluorescent dissolved organic matter(FDOM); principal component analysis; spatio-temporal distribution.