关键词: 水质变化;驱动力;长序列;水质指数法;蛤蟆石站;鄱阳湖;

Abstract: Exploring the water quality changes of lakes outflow and their driving forces are of great significance to the management and protection of lake water environment. Based on the water quality data of the Hamashi Section in Poyang Lake's outflow in the past 28 years(1991 ～ 2018),we used the Water Quality Index(WQI) method to assess the water quality of Poyang Lake outflow,and used the Mann-Kendall test method to analyze the change trend of the water quality indicators. At the same time,the key driving factors affecting the changes in the water quality of Poyang Lake's outflow were identified by the grey relational analysis method. The result showed that:in general,the water quality of Poyang Lake's outflow was good,and the total WQI index varied from 7. 00 to 27. 65. Dissolved Oxygen(DO) in the water body showed a decreasing trend,but the trend was not obvious. Concentration of Permanganate Index(CODMn) and Ammonia Nitrogen(NH3-N) showed a significant increasing trend,and their statistical valuesZwere 2. 53 and 3. 93 respectively. The total WQI showed a significant increasing trend,and its statistical valueZ was 4. 27. In the 1991 ～ 2018,the main driving factors for the changes in the water quality of Poyang Lake's outflow were population,regional GDP,tertiary industry and total grain output. The study results can provide a reference for the water environment and protection of Poyang Lake.

Key words: water quality change; driving force; long sequence; Water Quality Index method; Hamashi Section; Poyang Lake;