长江中下游圩垸水环境现状、成因和治理

Status,causes,and management of water environment in polders of middle-lower Yangtze River

长江中下游圩垸是重要的粮食生产基地和人口聚集区,也是重要的湿地资源,但其水环境却面临氮、磷等营养盐超标的富营养化问题。通过历史数据收集结合原位采样数据,系统梳理现有圩垸水体富营养化的研究,分析了圩垸水环境现状和成因。结果表明:圩垸水体中氮污染较磷污染更严重,湖泊、坑塘营养盐浓度明显高于沟渠、河道,下游太湖、巢湖圩垸富营养程度高于中游洞庭、鄱阳两湖;圩垸水环境演变以20世纪80年代和1998年洪水为节点,可以分为3个阶段;防洪和用水活动通过削弱圩垸内外水文连通和内部水体间纵、横和垂向连通影响圩垸水环境;主动蓄洪、建设环境水库,是协调圩垸水环境与水灾害、水资源关系的有效方法。研究成果可为促进圩垸水环境治理提供参考。

Polders in middle-lower Yangtze River are important food production bases and population gathering areas,as well as important wetlands.However,they are now facing severe eutrophication caused by excessive nitrogen and phosphorus.Through historical data collection and in-situ monitoring,as well as a systematically review of researches on the eutrophication of polder waterbodies,the paper discussed the current status and possible reasons of the water environment in polders.Results show that nitrogen pollution was more severe than phosphorus.Lakes and ponds had higher nutrient concentrations than ditches and rivers.Polders in Taihu and Chaohu Lake had higher eutrophication level than Dongting and Poyang Lake.1980s and 1998 The evolution of water environment was divided into 3 phrases:before 1980s,1980s-1998,after 1998.Flood control and water use activities weakened the hydrological connectivity between waters in and out polders,as well as lateral,longitudinal,and horizontal connectivity between the internal water bodies.Storing floodwater and building environmental reservoirs could coordinate the relationship between water environment,water disasters,and water resources.The research can provide basis for water environment management in polders.