抚仙湖、星云湖与杞麓湖营养状态演变及突变分析

Evolution and Change-Point Analysis of Trophic Status of the Fuxian Lake,the Xingyun Lake and the Qilu Lake

为科学评价抚仙湖、星云湖和杞麓湖(简称三湖)营养状态及其变化趋势,基于三湖1991-2015年水质数据,采用综合营养状态指数法评价其富营养化水平,通过Mann-Kendall(Sneyers)方法判识三湖富营养化趋势及突变时间。结果表明:三湖都存在水质恶化现象,其综合营养状态指数及各分项指数均呈变差趋势,表征其营养物质在增加。三湖的营养化水平和演变时间存在显著差异,抚仙湖处于贫营养,星云湖由中营养转变为富营养,杞麓湖表现为中度-重度富营养化;抚仙湖和杞麓湖分别在2004、2011年出现突变点,星云湖自2000年后综合营养状态指数显著增加。基于三湖营养状态演变及趋势,结合变化特征及相关情况的讨论,提出对抚仙湖的管理应减少农业化肥和农药排放,对星云湖和杞麓湖的管理应削减高污染工矿企业排放等。

In order to scientifically evaluate the trophic status and changing trends of the Fuxian Lake,the Xingyun Lake and the Qilu Lake(the Three Lakes for short),based on the water quality data in local area from 1991 to 2005,this manuscript evaluated the eutrophication level of these lakes by the comprehensive trophic state index,and then explored the change points and trends of the trophic status with Mann-Kendall(Sneyers)test.The results showed that water quality deterioration and trophic status increasing occurred in the Three Lakes obviously from the comprehensive trophic state index and each sub-index.The eutrophication level and evolution time of the Three Lakes were significant differences.the Fuxian Lake was always in a state of oligotrophic.The eutrophication degree of the Xingyun Lake changed from mesotrophication to eutrophication significantly,and the Qilu Lake had a middle-hyper eutrophication change process.the Fuxian Lake and the Qilu Lake reached their change points from a state of the trophic value to another in 2004 and 2011,respectively.The comprehensive trophic state index of the Xingyun Lake had increased significantly since 2000 though no change points turn up.By exploring the time and characteristics of the eutrophication evolution of the Three Lakes,combining with the change characteristics,and change trend of social and economic activities in different periods,this paper put forward some suggestions on reducing agricultural fertilizer and pesticide emissions in the Fuxian Lake and reducing the emissions of high-polluting industrial and mining enterprises in the Xingyun Lake and the Qilu Lake.