基于SWAT模型的小清河流域氮磷污染负荷核算及总量控制

	基于SWAT模型的小清河流域氮磷污染负荷核算及总量控制
其他题名	环境水文过程及模拟
	王琼 1,2
学位类型	硕士
导师	张华
	2012-05-16
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	环境工程
关键词	小清河流域 Swat模型总氮总磷总量控制
摘要	随着人口总量持续增长，工业化、城镇化快速推进，农村环境污染加剧、生态功能退化，环境日趋脆弱，其中水污染问题尤其突出。国家颁布的 “十二五规划”将化学需氧量和氨氮减少排放量的量化指标纳为改善水体整体水环境的约束性指标，但是在一些重点流域中，某些河段或整个水系却面临着更加严重的总氮、总磷水质超标问题，因此总氮和总磷污染将严重阻碍我国重点流域水环境质量提升的进程。本研究以小清河流域作为研究区域，结合不同时期对水质进行野外监测数据，应用多元统计方法来识别流域不同形态氮磷浓度的时空分布特征的基础上，利用空间分析和相关分析方法识别流域不同土地利用方式对氮磷输出的影响。并对流域的空间和属性数据进行收集分析，构建了SWAT模型所需的数据库文件来表征小清河流域的实际情况，并同SWAT模型进行耦合，在参数敏感性分析和校准验证的基础上，模拟了小清河流域的水文循环、泥沙运移和营养盐迁移转化的过程，根据结果进一步分析不同污染源氮磷负荷对河流水质影响，并结合不同情景下的削减效果不同，最终确定能满足水功能区的总量控制方案。主要研究结论如下：（1）整个流域氮污染严重，其中总氮(TN)超标率达到100%。氨氮(NH₄-N)、磷酸盐(PO₄-P)浓度汛期显著高于非汛期，硝态氮(NO₃-N)浓度则非汛期显著高于汛期。TN、TP、NH₄-N、PO₄-P、TDP的浓度与集水区城市和工业建设用地的面积比例呈显著正相关；NO₃-N浓度与耕地面积比例呈显著正相关，与草地、林地面积比例呈显著负相关。空间上，不同子流域的氮磷分布特征被划分为3类：第1类和第2类主要集中在干流及北部平原区沿途接纳点源排放，氮磷浓度总体较高且空间差异较大；第3类流域主要位于南部山区，建设用地比例较小，污染程度相对较低。（2）小清河流域内人为排放的氮磷总量中非点源污染所占比重较大，其中贡献率最大的是化肥施用和畜禽养殖。化肥施用量在空间上具有一定的差异性，如位于章丘市和寿光市的子流域氮肥施用密度为250~330 kg/ha，高于整个流域的平均施肥密度，且高于发达国家对化肥施用的安全上限临界值225 kg/ha。流域内畜禽养殖废物中氮磷的年均排放密度也存在空间差异性，其中章丘市年均排放密度高达309~351 kg/ha，高于整个流域的平均排放密度。（3）小清河流域内不同污染源对污染入河总量具有不同贡献率，97%的总氮和99%的总磷均受人为活动源影响。总氮污染中化肥流失和畜禽养殖污染的比例最大，分别占了总氮的33%、29%；总磷污染中工业和城镇污水源比重最大，分别为55%、37%。居民生活源对氮磷污染的贡献比重均较小。由此得知，小清河流域内氮污染主要受到较大程度的非点源影响，而磷则主要受到点源影响。（4）基于SWAT模型的模拟结果，针对点源和非点源污染，设置了两种削减情景。每种情景对小清河水质都起到一定的改善作用，但是总氮最终仍无法实现水质功能区的要求，而其中控制点源废水中磷排放标准的情景相比于控制非点源控制的削减情景，削减效果更好。根据不同情景的不同削减效果，同时从点源和非点源两个方面进行定量控制，最终实现对小清河流域的总量控制，达到小清河水功能区对水质的要求。
其他摘要	Pollutants from industrial and urban continue to increase and gradually concentrate during the rapid development of urbanization and industrialization. However. The sewage treatment capacity is fall behind the level of economic development, causing the point source pollution load to increase, coupled with nonpoint source pollution. Thus, the water quality of rivers, lakes and other water-bodies in the recent years has a serious degradation, with the aquatic ecosystems function destruction. National “12Th five-year plan” for environmental protection adds the chemical oxygen and ammonia indicators to improve the water environment .But, in some key watersheds, the exceed problems of total nitrogen and total phosphorus are more prominent which severely restrict water environmental quality improvement. This research investigated water quality of Xiaoqinghe Watershed during rainy and dry season in the year 2012-2013. Factor analysis and cluster analysis were conducted to identify spatio-temporal distribution Characteristics of various forms of nitrogen (N) and phosphorus (P) in the watershed. Meanwhile, spatial analysis and correlation analysis were carried out to identify effects of various land use types on N and P export. SWAT model constructed by collecting and analyzing spatial and attribute data in the Xiaoqinghe watershed can characterize the actual situation and simulate the hydrological cycle, sediment transportation, nutrients migration and transformation based on the sensitivity analysis ,calibration and verification for parameters. Further analyzing the simulation results ultimately determine the total pollution amount control scheme to meet the requirement of functional area for water quality. The main results of this research are listed as following : 1 Nitrogen nutrients are parameters causing water quality impairment throughout the watershed, especially the exceeding standard ratio of total nitrogen is 100%. Ammonia nitrogen (NH4-N) and orthophosphate-phosphorus concentrations (PO4-P) are significantly higher in rainy season than in dry season, whereas nitrate nitrogen concentration is higher in dry season than in rainy season. TN, TP, NH4-N, PO4-P and TDP concentrations have a significantly positive correlation with percentage of residential and industrial build-up area in the watershed; NO3-N concentration is positively correlated with area percentage of cropland and negatively correlated with area percentage of forestland and grassland. Spatially, distribution characteristics of nitrogen and phosphorus by cluster analysis were identified three groups: the first and second groups located on southern part of the watershed, have low area proportion of build-up area and relatively less pollution; on the contrary, the third group locating northern plain of the watershed is seriously polluted by N and P loading from point sources along the stream reaches. 2 Non-point source pollution in the Xiaoqinghe watershed has a larger proportion among the total anthropogenic emissions. Fertilizer and livestock activities emissions for nitrogen are the most important contribution source. Fertilizer pollutant source has some differences in space. For example, the annual fertilization density in sub-basins located in Zhangqiu city and Shouguang city are 250~330 kg/ha, higher than the upper safe limit which is 225 kg/ha. the annual emissions of nitrogen and phosphorus from livestock pollutants also has the spatial differences. The nutrient carrying amount of nitrogen per hectare from livestock discharge in Zhangqiu city is as high as 309~351 kg/ha. 3 The different pollutant source has different contribution ratio in Xiaoqinghe watershed. Human activities seriously impact on the water quality, in which 97% of the total nitrogen load and 99% of the total phosphorus load into river is caused. The contribution ratios of fertilizer runoff and livestock pollution are 33% and 29% for the total nitrogen loads. The contribution ratios of industrial emissions and residents emissions are 55% and 37% for total phosphorus. The rural dweller emissions have the smallest impact on annual loads for total nitrogen and total phosphorus. 4 This research sets up two types of programs based on the simulation results by SWAT model for the point and non-point pollution source. Those scenarios all can improve the water quality, but it still can not achieve the requirement of water function. Controlling the emissions of point source can get better result compared fertilizer and livestock discharge, especially the phosphorus load into river was been cut more than 17% loads. Depending on the reduction effect of different scenarios, the total pollution amount control scenario from point and non-point sources can ultimately meet the water quality requirement of functional area in Xiqoinghe watershed.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/7923
专题	中国科学院烟台海岸带研究所知识产出_学位论文
作者单位	1.中国科学院烟台海岸带研究所 2.中国科学院大学
第一作者单位	中国科学院烟台海岸带研究所
推荐引用方式 GB/T 7714	王琼. 基于SWAT模型的小清河流域氮磷污染负荷核算及总量控制[D]. 北京. 中国科学院大学,2012.

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