澎溪河流域土地利用变化对非点源污染的影响研究

发布时间：2018-04-24 15:18

本文选题：澎溪河流域 + 土地利用变化　；参考：《武汉大学》2017年硕士论文

【摘要】：三峡库区作为我国重要的淡水资源战略储备库,其水质状况对三峡库区和长江中下游地区居民的生产、生活用水安全、社会经济发展以及国家重大调水工程南水北调的成败产生深远的影响。随着社会经济的飞速发展和生产活动的加强,三峡库区的土地利用发生了巨大的变化,由此产生大量的非点源污染物进入河流,对库区河流水质产生了巨大的影响。本研究以三峡库区典型流域澎溪河作为研究对象,运用SWAT模型模拟澎溪河流域的非点源污染负荷,分析流域下垫面变化对非点源污染的影响规律,并从水文响应单元(HRU)尺度分别探讨土地利用、土壤和坡度对非点源污染的影响,剖析流域非点源污染负荷的分布规律,从而为该流域以及三峡库区其他流域土地利用合理规划和流域水环境治理提供重要的技术支持。取得的成果如下:1.基于澎溪河流域的DEM、土壤、土地利用及气象数据,构建澎溪河流域非点源污染SWAT模型,利用2010-2014年实测水文、水质数据对模拟的流量、总氮和总磷浓度进行参数率定与模型验证,率定期与验证期的R2和ENs均在0.71以上,具有较好的模拟精度,满足研究区域模型模拟的要求。2.利用验证后的SWAT模型模拟澎溪河流域非点源污染的时空分布规律,2010-2014年的总氮、总磷负荷的时间分布随降雨变化而变化,总氮、总磷负荷与降雨量的相关系数分别为0.783和0.768,总氮负荷较总磷负荷深受降雨影响。流域污染负荷高发区主要分布在流域干支流河道两侧地势低洼区,尤其是东河中下游和入长江口沿岸河道最大。3.澎溪河流域土地利用变化情况,从2000-2013年,土地利用面积变化最大的是林地,由占流域面积的47.79%增加到61.58%,增加了 13.79%;耕地、草地面积变化较大,分别由占流域面积的31.89%、19.63%减少到24.75%、11.96%,分别减少了 7.14%、7.69%,其他地类面积变化不大。4.基于2000年、2013年两期土地利用现状进行非点源污染模拟,探讨下垫面变化对非点源污染的影响,2013年土地现状下模拟结果中除流量外总氮、总磷负荷均小于2000年。基于模型HRU输出结果探讨不同坡度与土壤条件下对应的土地利用类型的年均氮磷负荷,得出在流域坡度和土壤类型相同的情况下,耕地的负荷最大,总氮和总磷的年均负荷分别为1631.47t和146.34t。
[Abstract]:The three Gorges Reservoir area is an important strategic reserve of fresh water resources in China. Its water quality is safe for the production of residents in the three Gorges Reservoir area and the middle and lower reaches of the Yangtze River. Social and economic development and the success or failure of the national major water transfer project south-to-north water transfer has a profound impact. With the rapid development of social economy and the strengthening of production activities, land use in the three Gorges Reservoir area has undergone tremendous changes, resulting in a large number of non-point source pollutants into the river, which has a great impact on the water quality of the reservoir area. Taking Penghuxi River, a typical watershed in the three Gorges Reservoir area, as the research object, the SWAT model is used to simulate the non-point source pollution load in the Penghuxi River Basin, and the influence law of the underlying surface change on the non-point source pollution is analyzed. The effects of land use, soil and slope on non-point source pollution were discussed from the scale of hydrological response unit (HRU), and the distribution of non-point source pollution load was analyzed. Therefore, it provides important technical support for rational land use planning and water environment management of the basin and other watersheds in the three Gorges Reservoir area. The results are as follows: 1. Based on the demm, soil, land use and meteorological data of Penghuxi River Basin, a SWAT model of non-point source pollution in Penghuxi River Basin was constructed. The simulated discharge, total nitrogen and total phosphorus concentrations were determined and verified by the measured hydrology and water quality data from 2010 to 2014. The R 2 and ENs of the periodic rate and the verification period are both above 0.71, which has good simulation accuracy and meets the requirements of the regional model simulation. 2. The SWAT model was used to simulate the temporal and spatial distribution of non-point source pollution in Penghuxi River Basin. The total nitrogen (TN) and total phosphorus (TP) load time distribution varied with rainfall. The correlation coefficients between total phosphorus load and rainfall were 0.783 and 0.768 respectively. The area with high pollution load is mainly distributed in the low-lying areas on both sides of the main tributaries of the basin, especially in the middle and lower reaches of the East River and along the Yangtze River Estuary. From 2000 to 2013, the biggest change of land use area was forest land, which increased from 47.79% to 61.58%, increased 13.79%, and the area of cultivated land and grassland changed greatly. From 31.89% of the basin area to 24.75% 11.96%, the area decreased 7.14% and 7.69%, and the other land area changed little. 4. Based on the non-point source pollution simulation of land use status in 2000 and 2013, the effects of underlying surface changes on non-point source pollution were discussed. The total nitrogen load and total phosphorus load in the simulation results in 2013 were all smaller than those in 2000 except discharge. Based on the HRU output results of the model, the average annual nitrogen and phosphorus loads of land use types under different slope and soil conditions were discussed. The results showed that the maximum load of cultivated land was obtained under the same slope and soil types in the watershed. The average annual loads of total nitrogen and total phosphorus were 1631.47 t and 146.34 t respectively.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52

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