【作者】 金婧靓；

【导师】 王飞儿；

【作者基本信息】 浙江大学 ， 环境工程， 2011， 硕士

【摘要】 非点源污染已经成为我国水环境恶化和湖泊富营养化的重要诱因,控制非点源污染对于改善区域水环境具有重要的意义。太湖流域社会经济发达,但水环境已经处于富营养化状态。农业非点源污染已经成为太湖水污染的主要来源之一。苕溪是太湖重要入湖河道,也是沿河区域主要的水源。鉴于此,本研究采用美国农业部开发的SWAT模型对苕溪流域的非点源污染进行模拟研究,构建苕溪流域非点源污染模型,对流域的非点源污染情况进行模拟和分析,为苕溪流域水环境综合整治提供科学依据与有效经验。。主要研究内容和成果如下：(1)根据现场调查和资料收集,建立苕溪流域非点源模型数据库,为模型运行提供支撑。利用苕溪流域的瓶窑大桥(东苕溪)和港口(西苕溪)两个站点的监测数据,对SWAT模型径流和水质参数进行率定和验证。模拟结果的误差分析表明校准后的流域非点源污染模型适用于该研究区,且模拟效果较好。(2)应用SWAT模型模拟结果,结合GIS地理信息系统,对研究区的产流、产沙、非点源污染输出进行了空间分析。结果表明,苕溪流域土壤侵蚀空间分布特征与降水空间分布有一定的相关性；苕溪流域非点源污染单位面积产生量,北部高于南部,东部高于西部,中部地区最少。(3)非点源污染模型模拟结果显示,耕地所产生的单位面积泥沙和污染物负荷远大于其他类型。降雨对流域非点源污染的输出有着直接影响,年内有机氮、硝态氮、氨氮产量呈不规则的“W”形态变化,在雨季前后期,营养盐的输出分别会有一个“小高峰”,因此雨季是流域内非点源输出的重点时段。研究区子流域平均坡度与子流域产生的泥沙负荷、有机氮负荷以及硝态氮负荷呈显著性相关关系。(4)基于不同施肥情况的情景分析表明,减少化肥施用量对研究区非点源污染的削减具有一定的效果,但并不显著。更多还原

【Abstract】 Non-point source pollution (NPS) was an important factor for water environmental deterioration and Lake Eutrophication. It is essential to control NPS to improve water quality in our country. Taihu Lake is the third largest freshwater lake in China. With economic and social development, an increasing amount of pollutants have been discharged into Taihu Lake and resulted in water pollution-eutrophication in particular. Agricultural non-point source pollution is a major source of water pollution source in Taihu Lake. Tiaoxi is an inflow river surrounding Taihu Lake, and is also the main drinking water source for local community.SWAT model developed by USDA Agricultural Research Service(ARS) was applied to estimate the NPS in Tiaoxi Watershed. By calibrating and validating with the observed data, the NPS model for study area was established. The pollution load of NPS in Tiaoxi Watershed was estimated and the factors for NPS were discussed with the model. The main content and results were as follows:(1) The database for SWAT in the study area was established to ensure the successful operation. The data from Pingyao and Gangkou stations were used for calibration and validation. Error analysis showed that the simulation results were fine and the model was applicable for the study area.(2) SWAT model was used to calculate the runoff, sediment and nutrient load in Tiaoxi Watershed. The results showed that there existed a good positive correlation between sediment and rainfall. According to the simulation results of 2008, nutrient load was higher in the north and east of the watershed.(3) According to the model results, farmland was the main source of sediment and pollutions, which produced much more nutrient load in unit area than other land use types. The runoff and the load of nutrients varied during the whole year and reached the peak in the rainy season. There existed positive correlation between discharge and rainfall. The same trend was also found in the output of sediment and nutrient load. Therefore the rainy season is the key time for the NPS control. The average slope of sub-basins was another important factor to the output of the load of sediment, organic nitrogen and nitrate.(4) Scenario analysis based on the fertilizer application showed that reduction of chemical fertilizer could reduce the output of NPS, but not significantly.更多还原