藏东南工程扰动小流域泥沙来源的复合指纹解析  

A composite fingerprinting analysis of sediment sources in a construction-disturbed small watersheds of Southeast Tibet

作　　者：李鑫[1] 施明明 曹龙熹 陈果[2] 王云[3] 姚连福 LI Xin;SHI Mingming;CAO Longxi;CHEN Guo;WANG Yun;YAO Lianfu(College of Earth Sciences,Chengdu University of Technology,610059,Chengdu,China;College of Ecology and Environment,Chengdu University of Technology,610059,Chengdu,China;China Academy of Transportation Sciences,100029,Beijing,China)

机构地区：[1]成都理工大学地球科学学院,成都610059 [2]成都理工大学生态环境学院,成都610059 [3]交通运输部科学研究院,北京100029

出　　处：《中国水土保持科学》2023年第4期113-122,共10页Science of Soil and Water Conservation

基　　金：第二次青藏高原综合科学考察研究任务“青藏地区高等级公路多年冻土段生态风险评估”(2021QZKK0203)。

摘　　要：工程建设在推动社会发展的同时也易导致严重的水土流失和流域环境问题。为明确工程扰动土壤侵蚀对流域水环境的影响范围和程度,选取西藏米林县派镇附近的公路建设扰动小流域,测定流域内潜在侵蚀源地和河道沉积泥沙的18种物化指标,使用复合指纹识别技术解析各侵蚀源地的泥沙贡献率及其空间分异特征。结果表明:流域内3类主要侵蚀源地的平均泥沙贡献率表现为道路及边坡(61.61%)>渣场(21.15%)>自然林草地(17.24%),说明工程扰动土壤侵蚀是河流沉积泥沙的主要来源。不同工程扰动类型泥沙贡献率的空间分异特征表现出集中分布的渣场泥沙贡献率沿沟道向下游呈线性衰减趋势,在本研究条件下的有效影响距离约为2800 m;与河流平行分布的道路边坡全程均产生泥沙贡献,其中在距道路约220 m范围内的影响最为显著,随着路河距离增大其泥沙贡献率呈指数函数衰减趋势。该研究成果可用于辅助预测工程扰动泥沙影响范围和贡献率,为研究区工程规划和修复措施布设等实践工作提供参考。[Background]Construction activities such as transport projects may promote social development.However,it could also lead to serious soil erosion and environmental problems.In recent years,intensive engineering and construction activities have been conducted in the middle Yarlung Zangbo River basin in southeastern Tibet,China.Consequently,the local fragile ecological environment has been seriously disturbed.Quantitative analysis and theoretical support for erosion control and engineering disturbance evaluation is urgently needed.A composite fingerprint study about the contribution of soil loss from construction disturbance and its spatial variation can be helpful in engineering planning and assist the optimal deployment of conservation measures.[Methods]Soil samples were taken from potential erosion sources including woodland,grassland,slag,road cutting and unpaved roads.Sediment samples were taken from riverbeds,and totally 18 physical and chemical parameters were measured.The best fingerprint combination of K 2 O,Na 2 O,CaO and Cr was selected using Kruskal-Wallis H test and multivariate stepwise discriminant analysis.A multivariate linear mixed model was used to analyze sediment contribution rate of each erosion source.The quantitative relationship between sediment transport distance and contribution rate was established to reveal its spatial variation.[Results]The best fingerprint factors combination reached an overall correctly classified percentage of 94%for the total source soil samples.The average sediment contribution of the three main soil loss sources was ranked as:Road and side slope(61.61%)>slag site(21.15%)>natural woodland and grassland(17.24%).The average value of goodness of fit(GOF)was calculated as 0.867.The results showed that soil erosion from engineering disturbance was the main source of sediment that deposited in riverbeds of the small watershed.The sediment contribution rates of the two engineering disturbance sources showed different spatial variability.Sediment from the spoil site follow

关 键 词：复合指纹法 公路建设 小流域 泥沙来源 藏东南地区 

分 类 号：S157[农业科学—土壤学]