【作者】 王孟；

【导师】 邬红娟；

【作者基本信息】 华中科技大学 ， 环境工程， 2004， 硕士

【摘要】 本文在对长江流域水库富营养化调查研究的基础上,首次从流域生态水文过程和水库水文情势两个方面研究了生态水文格局的变化与水库富营养化的关系,并对水库富营养化随机模型进行了有益的尝试,为生态水文学的发展提供了依据和理论基础。1.通过聚类分析和主成分分析等多元统计分析方法,本文对流域生态水文格局与水体富营养化关系进行了探索,研究发现流域内土地利用状况、人口密度和水滞留时间等生态水文因子是影响水库富营养化的主要因素。不同流域位置、不同功能的水库富营养化状况存在着较大差异。一般情况下,湖泊型水库富营养化程度高于河道型水库,以灌溉为主的水库富营养化程度高于以发电为主的水库。并且,伴随着水资源的短缺、水量减小,大部分水库的富营养状况有加剧的趋势。所调查的27座大型水库中包括14座河道型水库和13座湖泊型水库,其中河道型水库中营养程度为富营养的有3座,占河道型水库的21.4%;湖泊型水库中有9座富营养水库,占湖泊型水库的69.2%。显而易见,湖泊型水库富营养化程度远远高于河道型水库;以发电为主的水库中占30%已达到富营养标准,而以灌溉为主的水库中达到富营养的占53.8%。2.流域生态水文格局的不同决定了水库类型的不同,并进而导致了水库生态水文学特征的不同。不同类型的水库浮游生物群落差异明显,这些差异主要取决于水库的水动力学特征和营养盐水平。山地型水库具有较明显的河流特征,浮游植物的种类数和细胞密度均较低,有较多的河流种,无明显优势种;浮游动物的种类和数量很低,以轮虫和桡足类幼体为主。平原型水库一般位于流域下游,具有“丰水为河,枯水为湖”特点,浮游植物的种类数最多,其组成兼有河流种类与湖泊种类;浮游动物的种类较多,以桡足类幼体为主。3.水文情势的变化与水库富营养化有密切的关系。水文情势通过水位或水滞留时间的调节,对营养物质、藻类的组成和现存量进行调控,从而影响水体富营养化进程。水滞留时间的长短直接影响水库的水质状况和富营养化的程度,水力滞留时<WP=5>间越长,水库发生富营养化的风险就会增加。水滞留时间的延长为浮游植物的生长提供了优越的外部条件,有利于藻类的疯长,更易于发生水华。4.在确定性富营养化模型的基础上,本文对用随机模型预测水体富营养化进行了尝试。把水体富营养化过程看作一个随机过程对总磷的变化进行预测。因此,随机模型比确定性富营养化模型的优越之处在于它可以提供关于浓度变化的概率特性,比较符合实际,具有一定的应用价值。5.在对水库富营养化与生态水文过程关系研究的基础上,本文提出了水体富营养化的生态水文概念模型,为生态水文模型的研究提供了新的方向。更多还原

【Abstract】 Based on the investigation and assessment of large reservoirs in Yangtze Basin, this paper analyzed the causes and characteristics of the eutrophication occurred in these reservoirs. The relationships between ecohydrological pattern and eutrophication were researched in the view of ecohydrological processes of watershed and hydrological regime; stochastic model of eutrophication was also studied, which provided the theoretical basis for ecohydrology.Based on the methods such as clustering analysis and principal component analysis, this paper studies the relationship between the ecohydrological pattern of watershed and eutrophication. The results manifests that status of land usage, population denity and hydraulic retention time are the main factors influencing the eutrophication of reservoirs. Owning to the different location and function of reservoirs, significant differences exsist in eutrophic states. Water quality of the reservoir inflow was decided by soil types of watershed、status of land usage and vegetation coverage. The results showed that the eutrophic state is obviously related with the type and function of the reservoirs. The eutrophication level of lake-type reservoirs is higher than that of rive-type reservoirs; the eutrophication level of the reservoirs primarily for irrigation is higher than that of reservoirs for power generation. Among the 14 rive-type reservoirs and 13 lake-type reservoirs that have been investigated, 21.4% of the rive-type reservoirs and 69.2% of the lake-type reservoirs have been eutrophicated; 30% of the reservoirs for power generation have been eutrophicated, while the the ratio is 53.8% for reservoirs used to irrigate.The ecohydrological pattern of watershed decided both the type(types) of reservoirs and the hydrodynamics. The plankton communities in the reservoirs showed remarkable differences, which are closely associated with the hydrodynamics and nutrient levels in <WP=7>the reservoirs. Hill-reservoir has a short retention time; its phytoplankton community was characterized by low abundance and no obviously dominant species. The zooplankton was predominated numerically by rotifer and nauplii. Located at the downstream of the river continuous system, Plain-reservoir had higher number phytoplankton species and mediate cell density. The dominant species of phytoplankton were Chlorophyte and Bacillariophyta, and composed of both lacustrine and potamo phytoplankton. The zooplankton was predominated numerically by nauplii.It indicated that the level of eutrophication has high correlativity with the hydrological regime. Through regulating water level or hydraulic retention time, the composition of nutrition and standing crop of algae can be adjusted, therefore effecting eutrophication process. Delaying the retention time of water and reducing the flow speed are helpful for the sedimentation of nutrient, thus preventing the dilution of it, which is profitable for the growth of algae. Based on the Vollenweider model, a stochastic eutrophication model was built. The changing process of total phosphorus concentration was regarded as a random process in the model. Therefore, the model provides the random properties of total phosphorus concentration.Based on the relationship between eutrophication and ecohydrological processes, this paper put forwards the Hydrological conceptual model for eutrophication, which gives the new direction to the study of the hydrological model.更多还原