【作者】 李璐；

【导师】 蔡崇法； 史志华；

【作者基本信息】 华中农业大学 ， 资源环境信息工程， 2010， 博士

【摘要】 作为南水北调中线工程的水源区,丹江口库区的生态环境状况在水质安全和净化上具有重要作用,对整个南水北调工程及汉江盆地的经济发展也具有重要意义。本研究针对南水北调中线水源区生态环境的特征及生态环境主要问题,借鉴集成研究思路,基于丹江口水库水源区土地利用、森林植被现状及时空变化特征,结合地形、地质、地貌、土壤、降雨等自然环境因子,从“水源区—库区—小流域”多尺度、多方位、多角度、采用不同的方法研究生态环境状况、林地变化、土壤侵蚀、非点源污染的时空特征、土地利用的水文响应,全面了解研究区生态环境状况,并提出相关综合整治对策和措施,加强水源区生态环境建设,确保水源区水质安全,为中线水源区生态环境建设以及可持续发展提供科学依据。本研究取得以下主要结论和成果：(1)本文以南水北调中线水源区为研究对象,建立了水源区环境信息数据库,在此基础上,提出一种模糊层次分析法和GIS相结合的生态环境脆弱性评价方法。根据水源区生态环境状况及人为影响,生态环境脆弱性分为潜在脆弱性、轻度脆弱性、中度脆弱性、强度脆弱性、极强度脆弱性5个等级。结果显示：水源区整体生态环境处于中度脆弱性；轻度脆弱性区域主要分布在西北部秦岭山区、南部大巴山区及东部环丹江水库周边区域,极强度脆弱性区域主要分布在河南省内丹江口水库北部以及山西省西部。(2)以水源区遥感影像为主信息源,辅以DEM、植被分布图、土地利用图及相关社会经济资料,对该区域20年来森林覆盖的动态变化和区域分异特征进行了研究。采用典范对应分析(CCA)研究了林地分布及其变化与环境因子间的关系。研究结果表明水源区1980年、1990年、2000年林地面积分别为67631km2、61635km2、65051km2,斑块数依次为41790个、71276个、69632个,平均斑块面积为1.62 km2、0.86 km2、0.93 km2,呈破碎化趋势；林地分布主要由海拔、降雨和坡度等因素决定,而林地变化的主要影响因子是海拔、坡度和人口。(3)应用遥感和GIS技术,借助TM数据为信息源,在建立土壤侵蚀解译标志的基础上,对丹江口库区土壤侵蚀进行了监测研究。结果表明,1990-2007年间,丹江口库区水土流失状况逐步好转,表现在微度、轻度土壤侵蚀面积呈持续增加,中度以上土壤侵蚀面积呈减小的趋势。土壤侵蚀等级年变化率的排序为：剧烈侵蚀>极强度侵蚀>中度侵蚀>轻度侵蚀>微度侵蚀>强度侵蚀。总体而言,各个等级土壤侵蚀平均重心在经度上的变化大于在纬度上的变化。土壤侵蚀等级之间转化十分复杂,源于自然因素和人为因素的双重影响,库区土壤侵蚀仍处于边治理、边破坏的状态。(4)在已有研究的基础上,以1990、2000、2007三期TM影像为基础,解译出土地利用图,辅以DEM、气象数据及相关社会经济资料,在GIS支持下使用输出系数模型对库区三期非点源污染进行空间模拟和负荷估算。研究结果表明库区非点源污染TN、TP负荷1990～2007年间总量呈增长趋势,2000年以后增长速度加快,整体非点源污染形势恶化。旱地是库区最大TN负荷来源,人是主要TP负荷来源,人口增长、畜禽养殖业对库区TN、TP负荷贡献已经超过了土地利用。河南省淅川县非点源污染最为严重,应成为重点治理区域。(5)以丹江口库区的胡家山小流域为研究区,提取15个集水区对其土地利用结构进行分析,结果表明：胡家山流域的土地利用类型以旱地和林地为主,在各个集水区内,从上游到下游,旱地、居民地面积所占比例逐渐增大,林地所占比例逐渐减少。林地主要分布在高海拔、坡度15°-25°区域,旱地主要分布在低海拔区域,居民地主要分布在海拔350m以下较为平缓的区域。整体看来,整个流域土地利用类型距离河岸两边距离：林地>草地>居民地>农田。对整个胡家山小流域而言,呈现从上游到下游土地利用相对合理指数减少的趋势。(6)结合降雨气候资料和水质监测点的氮素输出数据,引入景观空间负荷对比指数,分析土地利用结构对氮素输出的影响。结果表明：胡家山小流域地表水非点源污染比较严重,各支流从上游到下游TN、NO3--N输出浓度呈逐渐增大趋势。林地、荒草地、水域与氮素输出浓度呈负相关；居民地、旱地等与氮素输出浓度显著正相关。在0.01显著水平上,相对高度、坡度和距离三者及其综合景观空间负荷对比指数与TN、NO3--N输出浓度均具有显著相关性,其相关程度高于加权重土地利用类型面积百分比之和Lw,高于任何单一土地利用类型。说明景观空间负荷对比指数对于发生非点源污染的空间风险具有很好的指示作用,可以作为非点源污染空间风险评价的有用方法。(7)提出以整个中线水源区为治理范围,以小流域治理为单元,以生态环境改善、水质保障为中心,采取整体规划,划整为零,再以零凑整,实现整个中线水源区的综合治理。水源区尺度侧重跨区域机构建立、开展水功能区划、建立特色生态保护区,并加强林地管理；库区尺度要做好移民安置工作,加强水土流失和非点源污染综合防治；小流域综合治理包括水土保持工程、生态农业、土地利用结构优化、农村污染资源化及植被缓冲带重建等。更多还原

【Abstract】 The Danjiangkou reservoir lies in the upper Hanjiang basin and is the source of water for the Middle Route Project (MRP) under the South-to-North Water Transfer Scheme (SNWT) in China. The eco-environment of water resource areas plays an important role in water conservation and purification and would have significant implications for the economic prosperity in Hanjiang basin as well as for the SNWT. According to the eco-environmental characteristics and primay reco-environment issues in water resource areas, referring to the ideas of integrated study, based on temporal-spatial characteristics of land use and forest vegetation, associated with natural environmental factors including terrain, topography, geology, soil, etc, multi-scale, multi-perspective, multi-approaches were included in the research involving eco-environmental vulnerability, forest change, soil erosion, non-point pollution and hydrological responses of land use from Water Resource Areas (WRA), Danjiangkou Reservoir Area.(DRA), to Hujiashan small watershed. Based on The research results above, the ending of this paper tried to bring forward several strategies and measures for comprehensive environmental rehabilitation to enhance the ecological construction and environmental protection and insure the safety of water quality, which will provide scientific basis for environmental construction and sustainable development in water resource areas. The present study came to make important results and achievements as the following.(1) This study established an environmental information system database of WRA. Based on the database, an eco-environmental vulnerability assessment method using integrated fuzzy AHP (FAHP) and GIS was developed. According to eco-environmental conditions and anthropic effects, vulnerability was classified into five levels:potential, light, medium, heavy and very heavy. The results indicated that eco-environmental vulnerability in the DRA was moderate overall. Regions with lower eco-environmental vulnerability were located in Qinling Mountain area in the northwest, Daba Mountain area in the south and the area immediately surrounding Danjiangkou Reservoir in the east. Two regions with very high eco-environmental" vulnerability were located in the north of Danjiangkou Reservoir in Henan province and in the western part of Shanxi province.(2) Based on sources of RS images, associated with DEM, vegetation distribution map, land-use map and the corresponding socio-economic data, this paper attempted to reveal the spatio-temporal dynamics of forest cover in recent 20 years, and then utilized the canonical correspondence analysis (CCA) method to study the relationship between forestland distribution or transformation and environment parameters. The results indicated that forestland area had decreased continuously from 67631 km2 in 1980 to 61635 km2 in 1990, and then it started to increase to 65051 km2 in 2000, and the average annual rate of change had gradually dropped from-9.3% during 1980 to 1990 to 5.4% during 1990 to 2000; meanwhile, the forest landscape had a fragmentation trend. The result of the CCA order showed that the major environment variables affecting forestland distribution were elevation, rainfall and slope, and the major environment variables affecting forestland transformation were elevation, slope and population.(3) Based on RS and GIS technology, the spatial and temporal variations of soil erosion were investigated for DRA. Interpretation characteristic indexes were established from remote sensing images and other data. Results showed that from 1990 to 2007, the total erosion area of the DRA was decreased; it shows concretely as follows:the area of light soil erosion has continually expanded and the area above the moderate soil erosion was reduced.The annual change in each soil erosion level was in the order of serious erosion> very strong erosion> moderate erosion> light erosion> slight erosion> strong erosion. Overall, the change ranges of the average center of gravity in longitude were far greater than latitude for each soil erosion level. Because of the dual influence of the nature factor and the artificial factor, the conversion between each soil erosion level was very complex, and soil erosiom was at management margin damage in DRA.(4) Based on the existing studies and the export coefficient model, the non-point source (NPS) pollution load in DRA was estimated and its spatial distribution in 1990, 2000 and 2007 were simulated with RS and GIS techniques. Results indicate that the pollution load of TN has a small change from 3.325 X 104 t in 1990 to 3.379X 104t in 2000, then it increased to 3.710×104t in 2007. The pollution load of TP were 167×104t, 0.169×104t and 0.186×104t respectively in 1990,2000 and 2007. The main source of TN pollution load was dry land, and most of the TP pollution load was from people produce. Xichuan country in Henan province was the worst non-point polluted, and should be the key administration area of controlling water pollution in the future.(5) With Hujiashan small watershed as the research area, we studied the structure characteristics of land use in 15 catchments. The results showed that the major land covers in the study areas are forest and upland, and the proportion upland and residential area gradually increased from upriver to downriver in each catchment, while the proportions of forest increased.forest mainly distributed in higher altitudes and in a steep slope (15°-25°); forest mainly distributed in lower altitudes; residential area mainly distributed in flat terrain below 350 m. In the whole watershed, the distances to river from the river was in the order of forest> grassland> residential area> upland. Relative rationality indices of land use showed a decreasing trend from upriver to downriver in Hujiashan watershed(6) This paper studied the effect of land use types on nitrogen export base on the dates of land use and nitrogen expoxt in Hujiashan watershed, and a landscape index named location-weighted landscape contrast index (LCI) was calculated to evaluate the effects of landscape components’spatial distribution and land use structure on nitrogen expoxt. The result showed that the nonpoint source pollution of surface water environment was very serious and in each branch the concentration of TN and NO3--N gradually increased from upriver to downriver. The concentration of TN and NO3--N were negatively correlated with forest, grassland and water body while significant positively correlated with residential area and upland. There were conspicuous correlations among the LSI related to relative elevation, slope, relative distance and integrated LSI with the concentration of TN and NO3--N at 0.01 level, which were higher than the sum of weighted area percentage of land use (Lw) and any single land use type. This tell us LCI was good indicators of nitrogen exports and thus have big potential in non-point source ponution risk evaluation. (7) Taking Water Resource Areas of MRP as the comprehensive management region, taking small watershed as basic unit, taking eco-environment improvement and water quality protection as center, the paper considered that comprehensive planning should be used to realize comprehensive improvement. At WRA scale, it was need to establish management Institution across the region, develop water function zoning, establish special ecological protection zones and enhance the construction and preservation of the forests. At DRA scale, doing migration settlement work well and strengthening comprehensive prevention of soil erosion and non-point source pollution should be placed on the prominent position. At small watershed, it was imperative to take measures of comprehensiue treatment, including soil and water conservation project, ecological agriculture, optimizing land use structure, utilization of rural disposals and vegetative environmental buffers, etc.更多还原