Analysis of Water Environmental Characteristics of Reservoir in the Central Area of Yunnan Province by the Case of Twenty-eight Reservoirs in Chuxiong Prefecture

Through field monitoring and laboratory analysis, water temperature, pH, dissolved oxygen, turbidity, conductivity, chlorophyll-a, phycocyanin, and the stable isotopes of hydrogen oxygen (δ D, δ¹⁸O) of 28 reservoirs in Chuxiong area are obtained. Based on the analysis of water environment characteristics and its change, the correlation between the water parameters was discussed through correlation analysis. The results showed that the change of water temperature was following the solar radiation. The pH value of the water body was 7-9.3, which is weakly alkaline to alkaline. The dissolved oxygen is 5.5-10.5mg/L, water temperature, pH, and dissolved oxygen decreased with the increasing of water depth. Affected by wind disturbances, the turbidity was high and increased from surface to bottom of water. The characteristic and change of conductivity were smaller with the total dissolved solids. The concentration of chlorophyll a in most reservoir waters was within 10μg/L, and the concentration of phycocyanin was less than 5000 cells /ml. As the main kind of algae species in these reservoirs, the vertical change of cyanobacteria are consistent with the chlorophyll a. Stable isotopes showed that regional precipitation was the main source of reservoir water supply. In some reservoirs, there was a significant positive correlation between the water temperature, chlorophyll a and pH, as well as phycocyanin and dissolved oxygen and pH.