【作者】 胥彦玲；

【导师】 李怀恩；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2007， 博士

【摘要】 随着工业点源污染控制水平的提高,非点源污染已成为当今水环境污染的主要污染源,而人类的土地利用是非点源污染的主要影响动因。不同的土地利用活动和管理模式会导致土壤侵蚀和营养物随地表径流流失,从而形成对流域的大面积非点源污染。陕西黑河引水工程是西安市的主要供水水源,其水质与水量直接关系到西安市300万市民的身体健康与西安市社会经济的可持续发展。其水源区处于秦岭北麓深山区,区内山高坡陡,土壤脊薄,世代栖居的农民只能靠“广种薄收”来维持生计,因而由耕作活动所产生的非点源污染是水源区的主要污染源。因此,进行黑河水源区不同土地利用格局下的非点源污染研究,提出控制流域非点源污染的土地利用优化管理模式及措施,对保护黑河水源具有现实意义。本研究旨在通过GIS与环境模型(SWAT2000)结合的技术手段和景观生态学的研究方法,探讨流域土地利用与非点源污染的关系,通过建立流域环境经济协调的最优化模型来探讨流域最佳土地利用开发和管理模式,进而从根本上提出了解决流域非点源污染的控制对策。取得了以下成果:1.建立流域非点源污染研究的基础数据库。采用美国ESRI公司提供的ARCGIS软件以及ArcView扩展模块为平台,建立流域数字高程模型(DEM);通过遥感解译软件ERDAS8.5解译遥感图像获得两期(2000年和1976年)土地利用类型图;对黑河流域1:2000的土壤类型图数字化并进行校准获得研究区域的土壤类型图。从而为非点源污染的研究提供了基础数据库。2.通过对SWAT2000模型的率定、模拟与验证,分析和评价了SWAT2000模型在黑河流域的适用性和可靠性。从本研究率定与模拟结果来看,水文部分的模拟误差基本在15%以内,泥沙部分的误差大部分在20%以内,各主要非点源污染物的误差在25%以内,满足模型率定要求。这样的结果表明:率定后的模型具有一定的精确度,可用于研究区非点源污染过程的模拟研究。3.运用径流差值法来估算流域非点源污染负荷。根据非点源污染的产生受降雨径流过程的影响,其负荷与降雨径流具有密切的相关性的特点,建立了非点源污染负荷的估算方法——径流差值法。应用该方法来估算流域非点源污染负荷,为解决实测资料短缺的条件下流域水质估算提供了一种计算方法。4.通过不同土地利用情景非点源污染负荷的定量化研究,分析了土地利用对非点源污染的影响。在SWAT2000模型参数率定结果的基础上,从土地利用恶化与改善两个角度考虑,将土地利用设置为5种情景,运用该模型对这5种情景下的非点源污染负荷进行了模拟,并对模拟结果进行了对比分析,其结果表明:(1)林地可有效削减非点源污染负荷;(2)流域现状土地利用下总氮、总磷的负荷量分别为173.334t和38.653t,流域水环境存在着潜在的威胁,未来水环境的保护关键在于土地的合理利用及有效管理;(3)当黑河流域土地利用恶化为红草河流域时,流域水质会遭到极大地恶化,反之,随着水源涵养林保护工程的实施,林地面积逐渐增加,流域环境也会逐渐得到改善;(4)理论联系实际,为了有效改善流域水环境,控制非点源污染,未来土地利用将要达到的土地利用最佳状况为,响应国家水源保护政策,流域人口逐渐搬离,15o以上的坡地全部还林,在满足源头水水质标准情况下,允许15o以下坡度中有少量适宜农耕的耕地,无未利用地,且植被覆盖较好。在该土地利用情景下,林地的非点源污染氮的单位负荷为0.67kg/ (hm2·a),磷的单位负荷为0.11kg/ (hm2·a);耕地的非点源污染氮的单位负荷为8.85kg/ (hm2·a),磷为4.2kg/ (hm2·a)。5.黑河流域土地利用变化趋势与非点源污染的研究。用模型模拟与景观生态学方法结合,探讨了1976～2000年来土地利用变化对非点源污染的影响,得出如下结论: 1976～2000年这25年,土地利用的演化趋势向更合理、更有利于水环境保护的方向发展,林地面积逐渐增加,耕地和未利用地逐渐减少,且土地的合理化利用程度得到了极大地提高,但土地利用在不同坡度等级上的分布比例没有明显的变化,居民及工矿用地逐渐扩大,水环境仍存在着潜在的危险;为了保护水源区,未来应实施人口搬离政策,并继续加大植树造林的力度和水源保护政策实施力度,限制开采业和人为扰动,政府应继续发挥主导作用,引导居民更合理地利用土地,特别是更合理地利用15o以上的坡地。6.建立流域土地利用环境经济协调最优化模型。在土地利用情景模拟的基础上,考虑当地的经济产出与水环境保护,建立了流域土地利用环境经济协调最优化模型,其求解结果表明:未来土地利用达到的最佳利用状况为15o以上的坡地全部还林,在满足饮用水源水质标准的情况下,允许15o以下坡地中有4.24 km2适宜农耕的耕地,无未利用地,且植被覆盖较好。7.针对未来流域土地利用与管理,提出了非点源污染控制的措施。针对流域非点源污染负荷与流域人类活动密切相关的特点,从流域土地合理利用与管理方面,提出了非点源污染控制与治理的措施。更多还原

【Abstract】 With the effective control of industry point source pollution, the non-point source pollution has already become main pollution source in water environment nowadays. However, the land use is the main affecting driver of non-point source pollution. Different land use activity and management mode are able to lead to soil erosion and the nurture loss with surface runoff , which form the large area non-point source pollution to watershed.Shaanxi HeiHe diversion project is the main water supply source in Xi′An City. Its water quality and water quantity is related to the healthy of 3 million citizens and society economy sustainable development of Xi’An City directly. The water source area lies deep Qinling north mountain area, the slope is steep and the soil is infertile in the area. The peasant of perch for generations can only depend on "extensive cultivation" to maintain a living. Thus the non-point source pollution from cultivation activity is the main pollution source of the water source area. Therefore, studying the non-point source pollution based on different land use pattern and putting forward land use optimization management mode and measures of non-point source pollution control have practical signification in protecting HeiHe water source.Through union technique means of GIS and the environment model (SWAT2000), this study discusses the relationship between watershed land use and the non-point source pollution. By establishing basin optimization model of harmonization between environment and economy, this study discusses the best management pattern of land use. Accordingly, this study proposed the solution countermeasure of non-point source pollution control. The main content and innovative achievements are as follows:1. The foundation database of Heihe watershed non-point source pollution research is established. Using the ARCGIS software and the ArcView expansion module as platform, this study establishes DEM. Two period land use type maps (2000 and 1976) are acquired using remote sensing interpretation software ERDAS8.5. The soil type map is acquired by digitizing the Heihe rivers watershed 1: 2000 soil type map. Consequently, the foundation databases for the non-point source pollution research. are provided.2. Through SWAT2000 model adjusting, simulating and verifying, the serviceability and reliability ofSWAT2000 model are analyzed and evaluated in heihe river watershed. The results of the research show that the simulate error of hydrology part is within 15%, the calculation error of Sedimentation is within 20%, and the error of every main non-point source pollution is within 25%, which has satisfied the request of model adjust. Such indicates that the model has certain precision after calibration, which can be applied to the research of non-point source pollution.3. Using runoff-deduction method estimates the non-point source pollution load. Based on the traits of NSP affected by rain-runoff process and NSP being closely correlative with runoff, the runoff-deduction method is proposed. By this method, the monitored water quality data is divided into point source pollution and non-point source pollution.4. Through the quantitative study of non-point sources pollution loading of 5 scence of land use, the impact of land use to non-point sources pollution is analized. On the base of calibrating model parameter of SWAT2000, land use can be considered from deterioration or improvement and divided into 5 land use scenes. The non-point source pollution loads under 5 land use scenes are simulated by SWAT2000 respectivily, and the results of simulation are compared and analyzed. The results shows(:1) Forestland can reduce non-point sources pollution loading effectually. (2)the total nitrogen and total phosphorus loads is respectively 173.334 t and 38.653 t under present land use condition t. There is potential threat in the basin water environment. The protection key of water environment is reasonable land use and effective land magement in the future. (3)when land use of the heihe river watershed worsens and becomes into the scence of hongcaohe river watershed, the water quality of the area will be deteriorated greatly. On the contrary, with the implementation of the policy of watershed forest protect project, the area of forest land will be a gradual growth and the environment of watershed will be also improved. (4) Combining theory with practice, in order to improve the water environment of watershed and control effectively non-point source pollution, the future land use should attain the best condition that slope field above 15°should completely return to forests, allowing a few farming land in the slope field under 15°, unused land inexistence, vegetation cover being well. Under the scene of land use, the non-point source pollution nitric unit-load of forest land is 0.67kg/ (hm2·a), the non-point source pollution phosphorous unit-load of forest land is 0.11kg/ (hm2·a), the non-point source pollution nitric unit-load of cultivated land is 2.73kg/ (hm2·a) and the non-point source pollution phosphorous unit-load of cultivated land is 1.38kg/ (hm2·a).5. The reasearch on regional land use change trends and non-point sources pollution. Combining model simulation with landscape ecology, this study discusses the impacts of land use to non-point source pollution in recent 25 years, which draws such conclusion: (1)The trends of land use change are developing towards the more reasonable and more advantageous direction in protecting water environment. (2) Forest land areas have been expanding every year. The cultivated land and unused land are reducing gradually. The rationalization degree of land use is advanced greatly, but the change of land use distributing proportions in the different slope grades is not obvious. And the areas of resident and industry-mining land are increasinggradually. The water environment faces a potential danger. To protect water source region, population removing police should be carried out, the efforts of tree planting and water source protection should be intensified, mining industry and man-made effect should be limited, and government should exert continually leading action to lead dweller using land more advisablely, especially above 15°.6. The watershed optimization method about land-use, economic and environment is set up. On the base of scence simulating of land use, considered the local economical produce, the optimization method about land use, economy and environment is set up. The calculation results indicate that the sloping field above 15°will be completely returned to forest, the farm land in slope field below 15°is not more than 4.24km2 , unused land is not existent, and the vegetation coverage is very well.7. As far as land use and management of watershed is concerned, the measures of non-point source pollution control are put forward. Based on the trait non-point source pollutant load being closely related to human activities, the measures of non-point pollution control are proposed.更多还原