三峡水库水质时空变化特征及影响机制研究  

Spatio-temporal variation characteristics and influence mechanisms ofwater quality in Three Gorges Reservoir

作　　者：习文祥 祝贤彬 潘红忠[1,2] 姚华明 刘明亮 XI Wenxiang;ZHU Xianbin;PAN Hongzhong;YAO Huaming;LIU Mingliang(Hubei Key Laboratory of Petroleum Geochemistry and Environment,Yangtze University,Wuhan 430100,China;College of Resources and Environment,Yangtze University,Wuhan 430100,China;Hubei Key Laboratory of Intelligent Yangtze and Hydroelectric Science,China Yangtze Power Co.,Ltd.,Yichang 443000,China)

机构地区：[1]长江大学油气地球化学与环境湖北省重点实验室,湖北武汉430100 [2]长江大学资源与环境学院,湖北武汉430100 [3]中国长江电力股份有限公司智慧长江与水电科学湖北省重点实验室,湖北宜昌443000

出　　处：《人民长江》2024年第2期41-50,共10页Yangtze River

基　　金：智慧长江与水电科学湖北省重点实验室开放基金项目(ZH2102000113,ZH2002000113);湖北省教育厅科学技术研究计划青年人才项目(Q20211310);国家自然科学基金青年科学基金项目(41902257)。

摘　　要：三峡工程建设运行后水库生态环境问题一直备受关注,水质状况复杂且不断变化,但在水库调度下水库水质时空特征及影响机制仍需探究。基于三峡水库2021年11个长江干流断面和2个支流断面的监测数据,利用水质指数(WQI)评价水库水质状况,并结合主成分分析(PCA)、Pearson相关性分析、单因素方差分析(One-way ANOVA)及随机森林(Random forest,RF)方法探究三峡水库在调度影响下水质的时空变化特征及影响机制。结果表明:①从空间尺度上看,各水质参数的变化具有明显的空间异质性,总体上水质状况从上游至坝前(朱沱到巫峡口断面)有所好转,朱杨溪断面的水质情况最差;②从月尺度上看,不同水质参数和WQI随年度水库调度规划期发生变化,TP和COD_(Mn)的浓度总体上呈现汛期(6~9月)>消落期(1~6月)和蓄水期(9~10月)>高水位期(10~12月)的特征,而DO、pH及WQI与前者相反,在消落期下降,汛期相对稳定,在蓄水期逐渐上升;③生态调度有益于提升三峡水库水质,推测由于2021年5月29日至6月3日和6月16~22日开展2次以“促进产漂流性卵鱼类繁殖”为目标的生态调度使得6月份水库水质明显提升;④多种统计分析手段结合RF方法表明,不同水质参数之间存在明显关联,TN、TP、NH 3-N及COD_(Mn)之间呈显著正相关(r>0.3,p<0.01),pH和DO呈显著正相关(r=0.428,p<0.01),各参数均显著影响三峡水库WQI(p<0.01),其中浊度是影响三峡水库水质的最重要参数。研究结果可为三峡水库水环境可持续发展和水资源合理配置提供理论依据。The reservoir ecological environment after the construction and operation of the Three Gorges Project has been a great concern.The water quality conditions in the reservoir are complex and constantly changing.However,the spatio-temporal variation characteristics and influence mechanisms of the water quality in the reservoir under the reservoir scheduling still need to be explored.Based on the monitoring data over 11 Yangtze River mainstream cross sections and 2 tributary cross sections in 2021,we utilized the water quality index(WQI)to evaluate the water quality in the reservoir,and combined principal component analysis(PCA),Pearson correlation analysis,one-way ANOVA and random forest(RF)methods to investigate the spatio-temporal characteristics and influence mechanisms of water quality in the Three Gorges Reservoir under the influence of reservoir scheduling.The results showed that:①From the spatial scale,the changes of each water quality parameter had obvious spatial heterogeneity.The overall water quality condition had improved from upstream to dam site(Zhutuo to Wuxiakou section),and the water quality condition of Zhuyangxi section was the worst.②From a monthly perspective,different water quality parameters and WQI changed with reservoir storage.TP and COD_(Mn) concentrations generally showed the characteristics of flood season(June to September)>drawdown period(January to June)and storage period(September to October)>high water level period(October to December).DO,pH and WQI,on the contrary,decreased in the drawdown period,were relatively stable in flood season,and gradually increased during the storage period.The ecological scheduling benefited the water quality in the reservoir.Two ecological schedules,from 29 May to 3 June and from 16 to 22 June,to promote the reproduction of drifting spawning fish,probably resulted in a significant improvement in water quality in the reservoir in June.④Various statistical analysis tools combined with RF methods showed that there were significant correlations betwee

关 键 词：水质 水库调度 水质指数 随机森林 三峡水库 

分 类 号：X524[环境科学与工程—环境工程]