三峡工程运行背景下洞庭湖近25年来水生态环境的动态研究  

Dynamic Study on the Water Ecological Environment of Dongting Lake in the Context of the Operation of the Three Gorges Project in the Last 25 Years

作　　者：严广寒 殷雪妍 汪星[1,2,3] 王丽婧[3] 田泽斌[1,2,3] YAN Guanghan;YIN Xueyan;WANG Xing;WANG Lijing;TIAN Zebin(National Engineering Laboratory for Lake Pollution Control and Ecological Restoration,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;State Environmental Protection Key Laboratory of Drinking Water Source Protection,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;State Environmental Protection Scientific Observation and Research Station for Lake Dongting,Chinese Research Academy of Environmental Sciences,Beijing 100012,China)

机构地区：[1]中国环境科学研究院湖泊水污染治理与生态修复技术国家工程实验室,北京100012 [2]中国环境科学研究院国家环境保护饮用水水源地保护重点实验室,北京100012 [3]中国环境科学研究院国家环境保护洞庭湖科学观测研究站,北京100012

出　　处：《三峡生态环境监测》2024年第2期78-86,共9页Ecology and Environmental Monitoring of Three Gorges

基　　金：三峡工程运行安全综合监测系统项目(2022年)。

摘　　要：三峡工程自2003年运行以来,对长江中下游水环境的影响备受关注。本研究基于25年来对洞庭湖11个点位的监测结果,分析了三峡工程运行背景下洞庭湖水情、水环境质量的时空变化特征,明确了洞庭湖水环境演变的主控因素。结果显示,1996—2015年,长江三口年均水量和输沙量分别为(1.83~10.46)×10^(10) m^(3)、(1.07~147)×10^(6) t,三峡工程运行后的入湖水量和输沙量分别降低了27%和87%;湖体主要水质指标总氮(total nitrogen,TN)浓度在1999—2022年显著上升,而总磷(total phosphorus,TP)浓度则明显下降,全湖处于中营养水平,而东洞庭湖则处于轻度富营养化水平;浮游藻类密度变化范围为(9.00~272.03)×10^(4) ind./L,且逐年上升,藻的优势类群逐渐由硅藻、隐藻向绿藻和蓝藻演替。整体来看,水文调节是维持洞庭湖营养平衡和水环境安全的关键要素。此外,加强农业面源污染控制,推进全面清洁生产,通过生境改善和生态修复来有效拦截入湖口及上游河流污染物是洞庭湖环湖经济带管理部门进行洞庭湖综合治理与水质提升的主要抓手。Since the operation of the Three Gorges Project in 2003,the impact on the water environment in the middle and lower reaches of the Yangtze River has attracted more attention.Based on the monitoring results of 11 sites in Dongting Lake over the past 25 years,this study analyzed the spatial and temporal characteristics of water conditions and water environment quality in Dongting Lake in the context of the operation of the Three Gorges Project,and clarified the main controlling factors for the evolution of the water environment in Dongting Lake.The results showed that from 1996 to 2015,the average annual water volume and sediment transport volume of the three Changjiang estuaries were(1.83~10.46)×10^(10) m^(3) and(1.07~147)×10^(6) t,respectively.After the operation of the Three Gorges Project,the lake water intake and sediment transport volume decreased significantly by 27% and 87%,respectively.The main water quality indicators of total nitrogen(TN)increased significantly from 1999 to 2022,while the concentration of tatal phosphorus(TP)decreased significantly,and the whole lake was the mesotrophic level,while East Dongdongting Lake was the mild eutrophication level.The phytoplankton density was(9.00~272.03)×10^(4) ind./L,and increased year by year.The dominant groups of phytoplankton gradually changed from diatoms and cryptophytes to chlorophyta and cyanobacteria.Overall,hydrological regulation is the key element to maintain the nutrient balance and water environment safety of Dongting Lake.In addition,strengthening the control of agricultural surface pollution,promoting comprehensive clean production,and effectively intercepting pollutants from the lake inlet and upstream rivers through habitat improvement and ecological restoration are the main measures of the management of the Dongting Lake Economic Belt to carry out the comprehensive management of Dongting Lake and water quality improvement.

关 键 词：洞庭湖 通江湖泊 水环境 富营养化 三峡工程 

分 类 号：X52[环境科学与工程—环境工程]