基于“源—汇”格局的山区流域面源污染评价与分区管理

发布时间：2018-08-25 07:18

【摘要】：农业集约化经营程度提高的同时,面源污染问题开始凸显,景观格局与面源污染的变化有着密切的联系。研究“源-汇”景观格局与面源污染的关系,对于面源污染防治具有重要意义。以胶东苹果主产区栖霞市为研究区,分别在2016年5月份和9月份进行实地采样,采集了61个水质样本,测定分析全氮(TN)、全磷(TP)、化学需氧量(COD)、铵态氮(NH4-N)、电导率(EC),借助SPSS和GIS技术,分析了不同子流域、干支流的水环境质量时空差异;以河流水质指标作为面源污染的指示物,利用相关分析分析了景观异质性与面源污染的关系;以此为基础,引入了反映生态过程的景观空间负荷对比指数,分析其与面源污染的关系,通过分区管理,提出管控措施,为栖霞市的面源污染治理提供理论依据。主要研究结果如下:(1)栖霞市6条主要河流的水质指标在不同时期表现出了一定的差异性,其中以TN超标最为严重,远高于地表水v类标准;同一河流不同断面内污染物浓度表现出了一定的时空差异性,从综合污染指数来看,栖霞市水质状况总体较好,处于Ⅲ类标准及以上的断面共达到了94.73%;河流的干流和支流水质状况在5月份和9月份并无显著差异性,各种水质指标的均值在5月份干流大于支流,在9月份则相反,支流大于干流。(2)栖霞市21个小流域各类用地面积比例差别较大,林地的面积占比为38.43%,是栖霞市土地利用最多的类型。土地利用面积比例与面源污染指标具有一定的相关性。耕地、园地、建设用地和未利用地面积与面源污染指标存在一定的正相关关系,是本流域内的主要“源”型景观。林地、草地和水域面积与面源污染指标存在一定的负相关关系,是本流域内的主要“汇”型景观。其中耕地和园地与面源污染指标的正相关性较大,林地与面源污染指标的负相关性较大。(3)景观格局指数与面源污染指标具有一定的相关性,其相关性表明:景观类型、景观形状越复杂,对各营养盐具有一定的截留能力,水体越容易受到污染;该区域内的优势景观为汇景观,且景观异质性越大,优势景观林地的汇类型作用减弱,耕地和园地的源景观作用加强。(4)源汇景观空间负荷对比指数在区域内表现出显著的空间自相关性,且与流域内各水质指标存在显著正相关性,且TN、COD和电导率在两个时期均存在极显著相关,可以作为反映面源污染的指示指标。(5)通过对流域进行非点源分区,非点源污染分区图与栖霞市垂直分异生态分区图类似,呈现出西南-东北走向,重度污染区分布在西南部的丘陵粮-果综合利用区上,面积为栖霞市的1/7,潜在污染区分布在亭口镇、庙后镇以及桃村镇的低山林木保护区,与轻度污染区、中度污染区的面积共占栖霞市总面积的80%,说明栖霞市的面源污染状况总体较轻。(6)对比两种分区模式,可以发现,其整体上有着相同的分布趋势,但是,基于景观空间负荷对比指数的分区所需要的数据量远低于基于多准则分析的分区,可以更方便的为非点源污染分区及治理提供理论依据。基于景观符合对比指数的分区图,因地制宜的提出各种措施。在高LWLI区的河流出口处,应加强对“汇”景观类型的保护,增加植被缓冲带,在坡地上植树种草,对降水所携带的泥沙、营养盐负荷起到一定的阻碍,加强对水体的保护。
[Abstract]:With the development of agricultural intensive management, the problem of non-point source pollution is becoming more and more serious, and the landscape pattern is closely related to the changes of non-point source pollution. Total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), ammonium nitrogen (NH4-N), electrical conductivity (EC) were measured and analyzed in 61 water samples collected in September and September. SPSS and GIS were used to analyze the spatial and temporal differences of water environmental quality in different sub-basins and tributaries. Based on the analysis of the relationship between landscape heterogeneity and non-point source pollution, the landscape spatial load contrast index reflecting ecological process was introduced, and the relationship between landscape spatial load contrast index and non-point source pollution was analyzed. The main river water quality indicators showed certain differences in different periods, TN exceeded the standard most seriously, far higher than the surface water V standard; the concentration of pollutants in different sections of the same river showed a certain spatio-temporal differences, from the comprehensive pollution index, the overall water quality of Qixia City is better, in the third category of standards and to the surface water V standard. The water quality of the main stream and its tributaries had no significant difference in May and September, and the mean values of various water quality indicators in May were larger than those of the tributaries, whereas in September, the tributaries were larger than those of the main stream. The ratio of land use area to non-point source pollution index has a certain correlation. Cultivated land, garden land, construction land and unused land have a certain positive correlation with non-point source pollution index, which is the main "source" landscape in the basin. There is a certain negative correlation between the indicators, which is the main "sink" landscape in the basin. The positive correlation between cultivated land and garden land and non-point source pollution indicators is greater, while the negative correlation between forest land and non-point source pollution indicators is greater. (3) Landscape pattern index and non-point source pollution indicators have a certain correlation, the correlation shows: landscape type, landscape shape. The more complex the shape is, the more easily the water is polluted. The dominant landscape in this area is sink landscape, and the greater the heterogeneity of landscape, the weaker the sink effect of dominant landscape forest land, and the stronger the role of source landscape of cultivated land and garden land. (4) The spatial load contrast index of source-sink landscape shows significant in the region. The spatial autocorrelation was significantly positively correlated with the water quality indexes, and TN, COD and conductivity were significantly correlated in both periods, which could be used as indicators of non-point source pollution. (5) The non-point source pollution zoning map was similar to the vertical ecological zoning map of Qixia. There is a southwest-northeast trend. The heavily polluted area is located in the hilly grain-fruit comprehensive utilization area in the southwest of China. The area is 1/7 of Qixia City. The potential polluted area is located in the low mountain forest protection area of Tingkou Town, Miaohou Town and Taocun Town. (6) Comparing the two zoning models, it can be found that they have the same distribution trend on the whole, but the data needed by the zoning based on landscape spatial load contrast index is far less than that based on multi-criteria analysis, which can provide a more convenient theoretical basis for non-point source pollution zoning and control. At the outlet of the river in the high LWLI area, we should strengthen the protection of the "sink" landscape type, increase the vegetation buffer zone, plant trees and grasses on the slopes, hinder the sediment and nutrient load carried by precipitation, and strengthen the protection of the water body.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52

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