长江上游泥沙负荷变化与人类活动退耦研究
文献类型：学位论文
| 作者 | 韦杰 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 贺秀斌 |
| 关键词 | 泥沙负荷 流域侵蚀 人类活动 长江上游 嘉陵江流域 |
| 其他题名 | Decoupling between sediment load and anthropic impacts in the Upper Yangtze River Basin |
| 学位专业 | 自然地理学 |
| 中文摘要 | 在全球变化和人类活动日益增强的背景下，严重的土壤侵蚀不仅导致耕地面积减少、土壤质量退化、流域内农业生产力下降等源地效应，还会产生水体污染、下游河道淤积引发水患等异地效应，引起一系列的生态和环境问题。人类活动对侵蚀产沙影响类型多样，作用机理复杂。对中、小尺度流域而言，河流泥沙负荷对单项人类活动的响应比较敏感，而大尺度上不同人类活动相互作用，影响互相平衡，很难识别河流泥沙变化的驱动力。论文以长江上游地区为案例，利用文献调研、核素示踪、退耦理论和通径分析等方法研究侵蚀产沙对人类活动的响应，推导基于降雨侵蚀力的侵蚀产沙人类活动系数简易算法，判识侵蚀产沙与人类活动时间序列上的退耦过程，分析经济活动、水土保持措施、社会发展与侵蚀产沙演变的动态关系，综合评价区域侵蚀产沙动态的驱动力贡献。取得的主要成果有： 一、采用滑动平均、双累积曲线和距平累积等数学方法研究了长江上游泥沙负荷特征及演变。长江上游泥沙负荷主要有单站时间尺度的“水大沙多，水小沙少”和区域空间尺度的“水沙异源”两个特征；各站泥沙负荷均出现一定波动，总趋势在减少；各流域净人类活动主导性影响差异较大，整个上游1991年后正向人类活动处于明显主导地位，且作用逐步增强；根据距平累积可将长江上游泥沙演变分为1950-1991和1992- 2005两个阶段，其中1950-1991又可以按1968、1979、1984三个节点分成四个时间段。 二、采用GIS手段研究了长江上游降雨侵蚀力空间分异和时程变化。降雨侵蚀力空间总体格局是东部高、西部小及“多中心”分布。年内分布主要在第9个半月至20个半月之间，其中7-9月分布最集中。年际变化来看，1950-2005年除个别年份外，大部分都在2500-3500 MJ·mm·hm-2·h-1，围绕3000 MJ·mm·hm-2·h-1波动，大部分站点的倾向率都为正，整个长江上游的平均倾向率为1.79％，区域平均降雨侵蚀力在增加，但增幅较小。 三、结合泥沙负荷演变和降雨侵蚀力研究，采用退耦理论研究了长江上游泥沙负荷演变与人类活动的退耦过程和人类活动对泥沙负荷演变的总体贡献。20世纪80年代中期前河流泥沙负荷较大，主要与“一五”、“大炼钢铁”、“三线建设”、农村改革前期不稳定因素等密切相关，而70年代河流泥沙负荷较小是受“农业学大寨”运动期间大搞农田基本建设和采取“挑沙面土”、“边沟背沟”等传统水土保持措施的影响，80年代中期后河流减沙明显，主要受社会经济稳定有序发展、水保工程的实施及大兴水库建设等影响；各流域人类活动对泥沙演变的贡献差别大，金沙江、乌江泥沙负荷减少主要是人类活动所致，人类活动对嘉陵江、岷江和整个长江上游泥沙负荷减少的贡献分别为91.2％、71.5％、95.1％。 四、采用文献调研、核素示踪、通径分析等方法研究了长江上游和嘉陵江两种流域尺度不同人类活动对侵蚀产沙的影响。各种人类活动中，土地利用方式的变化、水土保持措施的实施等通过影响侵蚀而减沙，水库等直接拦截淤积泥沙，而修筑公路等短期通过增加侵蚀而增沙，长期则通过拦截淤积而减沙。嘉陵江泥沙负荷总趋势在减少，总效应作用排序为：新修塘库>农村劳动力转移>累计治理面积>森林覆盖率>农村用电量>公路通车里程>旱地比例；对减沙的直接贡献顺序为：新修塘库>农村劳动力转移>累计治理面积>农村用电量>旱地比例>公路通车里程>森林覆盖率；每个因素通过其它因素的间接作用排序为：森林覆盖率>公路通车里程>农村用电量>累计治理面积>旱地比例>农村劳动力转移>新修塘库。森林覆盖率是各变量通过它对减沙产生影响的最大间接变量。 在本研究中，主要有以下创新： 一、基于降雨侵蚀力提出判识大流域侵蚀产沙变化驱动力的退耦指标(单位降雨侵蚀力的泥沙负荷)，推导出侵蚀产沙变化的人类活动系数简易算法，为定量评价人类活动与降雨变化对河流泥沙变化的影响进行了创新探索； 二、从大流域、中等流域、坡面等尺度初步分析了长江上游典型人类活动对河流泥沙变化的影响，采用通径分析对嘉陵江流域不同人类活动对泥沙负荷变化的贡献进行排序，为水土保持生态环境建设提供了科学依据和指标数据。 |
| 英文摘要 | In the context of global climatic changes and increasing intensified human activities, soil erosion is generally recognized to have both direct and indirect impacts, expressed in terms of onsite effect on agricultural production and offsite effect on floods and sedimentation. Sediment load represents an important measure of soil erosion, transportation, deposition and various intensities of human economic activities in river basins. Within the small or middle catchment, the riverine sediment load is sensitively susceptive to catchment erosion, but this is not always the truth in large basin where aggregation and buffering effects have damped and counteracted its driving forces. Even though there are significant responses, it is difficult to get a precise quantitative assessment of each driver. Therefore, attempt to elucidate the sediment response to large basin-wide human activities is in great need as to provide significant information for land management. The reach from the headstream to Yichang on the Yangtze River is chose as a case for its serious erosion and its role of ecological defence in western China. Literature and local investigations, radionuclide tracing soil erosion, conception of decoupling and path analysis are used to study responses of sediment yield to human impacts. The present paper attempts to propose the calculation method of anthropic share in sediment yield, identify the decoupling between the sediment load and human activities, and analyze the dynamic relation of the sediment load to economic activities, soil-water conservation and social development. Achievements in the paper mainly include the following: 1) Mathematic methods of rolling average, double accumulative curve and accumulative curve of anomaly are employed to study the sediment load characteristic and variations in the Upper Yangtze. Two main characteristics of the sediment load and runoff are summarized and they are same in step but different in sources. The general trend of sediment load in the study area is decreasing; however, human impacts on the sediment in the tributaries are markedly different. For the whole Upper Yangtze, the turning point of sediment load appears in 1991, therefore, the sediment load variation can be divided into two phases, that is, 1950-1991 and 1992-2005. 2) GIS is used to study spatial and temporal variations of the rainfall erosivity. Generally, rainfall erosivity in eastern part of the Upper Yangtze basin are greater than that of western region which has close relation to the ladder-shape topography. The distribution map showed several rainy centers, for example, Yaan and Huili. Except for some special years of flood or draught, the annual rainfall erosivity fluctuate around ca. 3000 MJ•mm•ha-1•h-1•a-1. Inner-annually, erosive rainfall is mainly between the 9th and 20th half-month and especially in the period from July to September. The trend line with slight increment demonstrated that the rainfall erosivity along with the calendar year increased but the variation is not significant. 3) Based on the above study on the sediment load and rainfall erosivity, the paper studies the decoupling relationship between the sediment load variation and human activities and the net anthropic impact on the sediment. Sediment increments before mid-1980s are due to the First Five Plan, the Great Leap Forward, the Great-three-line Construction and instable situation during the first several years of rural reforms. But the sediment decreases are linked to the traditional soil loss control measures, socio-economic development in order, soil conservation projects and mushrooming of reservoirs. Human impacts on the sediment variation differ from basin to basin. The sediment declines in Wu River and Jinsha River basins are almost induced by human activities. The net anthropic impacts on sediment decreases in the Min, Jialing and the upper Yangtze Rivers are respectively 71.5%, 91.2% and 95.1%. 4) The author uses the published data and data obtained by radionuclide tracing erosion to analyze the sediment load responses to various typical human activities. Among the activities, reservoirs construction for water regulation, hydroelectric power generation and flood control result in a substantial decrease in the downstream sediment through trapping sediment. Land use change and soil conservation practices controlled the sediment generation which directly reduced sediment load. For the road construction, it leads to sediment increase in the construction years but benefit soil conservation after the completion. In order to get more precise assessment, the author utilizes the path analysis to study the anthropic contribution to sediment decrease in the Jialing River basin. The results indicate that the sequence of the general human effects are followed as: reservoir construction, rural labor transfer, cumulative erosion control area, forest cover, rural electro-power consumption, road length, ratio of slopeland to cultivated land. Among of them, direct impacts of reservoirs on sediment decrease is in the first place, but whose most indirect impacts on sediment decrease is forest cover. This paper concerns two main scientific issues and they are: 1) To propose the simple calculation method of anthropic impact share in sediment yield as to identify the drivers of sediment variations and quantify climatic and anthropic impacts on sediment load in large watershed. 2) To analyze the dynamic relation of the sediment load to economic activities, soil-water conservation and social development in terms of large, middle and plot scales; and to compare impacts of various human activities on sediment load in the Jialing River as to provide information for land management and soil conservation planning. |
| 学科主题 | 水文地质学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-14 |
| 分类号 | TU8;TS7 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2183]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 韦杰. 长江上游泥沙负荷变化与人类活动退耦研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2008. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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