基于湖库水质目标的流域氮、磷减排与分区管理——以天目湖沙河水库为例  

Reduction of nitrogen and phosphorus emission and zoning management targeting at water quality of lake or reservoir systems:A case study of Shahe Reservoir within Tianmuhu Reservoir area

作　　者：李恒鹏[1] 陈伟民[1] 杨桂山[1] 聂小飞[1,2] 

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]中国科学院大学,北京100049

出　　处：《湖泊科学》2013年第6期785-798,共14页Journal of Lake Sciences

基　　金：国家自然科学基金项目(41030745;41271500);中国科学院南京地理与湖泊研究所"一三五"重点布局项目(NI-GLAS2012135005);中国科学院重点部署项目(KZZD-EW-10-04);江苏省自然科学基金项目(SBK200920953);溧阳市沙河水库管理处科研项目联合资助

摘　　要：湖库水环境保护在保障生产与生活用水、维系生态平衡、发展旅游等方面发挥着重要的作用.水质目标管理是保护湖库水质的最佳管理办法.本文以天目湖地区沙河水库及其流域为研究区域,建立模型模拟沙河水库流域的水文与水质,评估入库污染通量和主要来源;依据水质目标测算氮、磷污染的容量和减排量,结合土地的生态保护与开发适宜性评估,提出氮、磷污染分区减排和土地管控的对策和措施.研究结果表明,沙河水库氮、磷污染物入库通量分别为206.01和3.29 t/a,面源总氮和总磷分别占总入库量的85.7%和67.5%.不同土地利用类型氮、磷输出强度有显著差异,总氮输出强度依次为茶园>耕地>建筑用地>裸地>草地>退耕地>林地>河湖漫滩,总磷输出强度与地表覆盖度有关,依次为裸地>建筑用地>茶园>耕地>草地>退耕地>林地和河湖漫滩.从氮、磷输移过程来看,沙河水库流域总氮排放量为321.64 t/a,进入河流的为255.53 t/a,在河道输送过程中损失19.4%,最终有206.01 t/a进入水库;沙河水库流域总磷排放量为13.42 t/a,进入河流的为7.90 t/a,在河道输送过程中损失58.3%,最终有3.29 t/a进入水库.不同分区河流氮、磷滞留降解率有很大的差异,中田河总氮、总磷滞留降解能力最强,分别为34.71%和84.31%.2009年的通量计算结果显示,沙河水库总氮达到Ⅳ类水质目标需要的入湖减少量为32.01 t/a,入湖削减比例为15.50%,总氮达到Ⅲ类水质目标需要的入湖减少量为59.66 t/a,入湖削减比例为29.00%;总磷达到Ⅲ类水需要的入湖减少量为0.682 t/a,入湖削减比例为20.70%,总磷达到Ⅱ类水需要的入湖减少量为1.479 t/a,入湖削减比例为44.90%.为了实现基于土地利用的面源污染减排管控,选定植被覆盖度、水源涵养能力、地形坡度、土地利用、氮磷分区贡献量、与道路和村落距离等指标综合评估生态保护价值和开发适宜性Protecting the lake-reservoir water environment plays an important role in the water use for production and lives,maintenance of ecological equilibrium,development of tourism industry.Water quality target management is an effective way to protect the lake-reservoir water.This paper took Shahe Reservoir and its catchment within the Tianmuhu Reservoir area as the study area.By developing a catchment-scale hydrological and water quality model,hydrological flux and water quality in the Shahe Reservoir catchment were simulated,and N and P fluxes into the Tianmuhu Reservoir and their main sources were evaluated.Based on water quality target of the Tianmuhu Reservoir,environmental capacity for N and P pollutions and the amounts required for reduction were calculated.Integrating with the ecological protection goal and suitability assessment of land for development,strategies on zoning reduction of N and P pollutions and land regulation have been explored.The results show that the amounts of N and P flowing into the Shahe Reservoir are 206.01and 3.29 t/a,respectively,with 85.7％ and 67.5％ from diffuse sources.The difference in output intensity of N and P is significant between various land use types.Land use with the largest output intensity of total nitrogen is tea garden,and then followed in turn by farmland,built-up land,bare land,grassland,abandoned farmland,forests,and wetland.Output intensity of TP is closely related with the land surface coverage,from which bare land is the largest.The rest are built-up land,tea garden,farmland,grassland,abandoned farmland,forests and wetland in turn.From the perspective of N and P transportation processes,the output of TN from the whole catchment is 321.64 t/a,and input amount into the rivers is 255.53 t/a,with 19.4％ loss in river channels.Ultimately 206.01 t/a of TN flowed into the Shahe Reservoir.As for TP,the total amount from the catchment is 13.42 t/a.There is 7.90 t/a entering into the rivers,with approximately 58.3％ loss in the river channel,and finally 3.29 t/a flow

关 键 词：水质目标管理 面源污染 源解析 沙河水库 丘陵地区 流域分区 天目湖 

分 类 号：X52[环境科学与工程—环境工程]