【作者】 王魁；

【导师】 蔡德所；

【作者基本信息】 广西大学 ， 结构工程， 2013， 博士

【摘要】 水土流失是目前最严重的世界性环境问题之一,给全球和区域生态环境带来严重的影响。我国西南岩溶区是世界上最大的岩溶裸露连片区,面积约6.2×105km2,区域内地质条件复杂,岩溶极为发育,构成了独特的“二元结构”,地貌类型多种多样,生态环境脆弱,抗干扰能力差；同时西南岩溶区是我国少数民族和贫困人口的集中区域,长期的社会经济落后影响当地的生态环境保护和建设；脆弱的生态环境加上不合理的人类活动,使得区域内水土流失状况十分严重,很多地方甚至出现“无土可流”的石漠化状况,使得当地的生态环境和生态安全受到严重的挑战,对该区域社会经济发展造成了严重危害。为探索广西水土流失与石漠化分布规模、水土流失过程和形成演化机制,对水土流失进行科学预测、评价,广西区水土保持监测总站与岩溶地质研究所合作开展了“漓江上游流域水土流失遥感监测研究与生态基地建设”项目；本研究以此为契机,选取寨底地下河流域为研究对象,开展水土流失监测研究工作。本论文通过对寨底地下河流域水土流失的监测,采用传统监测和改进的模型监测相结合的方法,对岩溶区水土流失影响因素进行了详细的分析,采用实地监测和3S技术提取各监测指标,从而计算出流域水土流失量,并对区域水土流失敏感性进行了分析,构建了岩溶小流域水土流失监测体系。本文的主要结论如下：(1)通过河流产沙量的传统方法对流域水土流失进行了监测,结果表明：寨底地下河总出口2010年泥沙输出量2013.6t,而流域内地下河出口泥沙泥沙总输出量2922.81t,两者之间有909.21t的差距；可以说明岩溶区水土流失产生的泥沙并不能完全从地下河出口带出,其原因应该是有部分的泥沙在地下河中产生沉淀；从寨底地下河流域计算的数据上来看,约30%的泥沙留在地下河系统中。(2)针对岩溶小流域的土壤可蚀性因子的计算方法进行了改进,以土地利用方式为依据进行K因子的计算；通过RUSLE模型方法对流域水土流失进行了监测,结果表明：寨底地下河流域年均土壤流失总量为16655.44t,年均侵蚀模数为504.71t/(kn2·a);按照《岩溶地区水土流失综合治理技术标准》(SL461-2009)的划分,寨底地下河流域土壤侵蚀强度属于中度,其年均土壤侵蚀模数约为岩溶地区容许土壤流失量(50t/(km2·a))的10倍。(3)两种方法的结果相差较大,基于泥沙输出量的计算结果仅为基于RUSLE模型计算结果的12%-18%；基于地下河出口的水土流失量计算,寨底地下河流域土壤侵蚀强度属于轻度,而基于RUSLE方程的水土流失估算,寨底地下河流域土壤侵蚀强度属于中度；基于RUSLE方程的水土流失估算比较符合2005年7月至2007年5月期间的“中国水土流失与生态安全综合考察”结果。(4)对岩溶区水土流失空间格局的分析过程中,提出了“单位因子影响率”的概念,以数值的大小来表示影响土壤侵蚀的因子,如高程、坡度、植被覆盖、土地利用等对岩溶区水土流失的影响程度。(5)通过对寨底地下河流域水土流失敏感性分析,得到了流域内地下河出口处为水土流失最敏感性区域,在水土流失的分区治理和区域生态保护中,应注意对地下河出口区域的水土保持和生态环境的保护。(6)基于水土流失传统监测和模型监测的实施,以及对寨底地下河水土流失的分析,从目标、指标和实施三个层面对水土流失监测体系进行了讨论,通过对基于数据库技术的水土流失监测信息平台的论述,提出了完整的岩溶小流域水土流失监测体系。本文主要创新点如下：(1)通过对岩溶小流域水土流失的监测,得出了水土流失过程中约30%的泥沙(相对于小流域土壤流失总量)留在地下河系统中；(2)以土地利用方式为基础,结合试验方法,改进了RUSLE方程中土壤可蚀性因子K值的计算方式,使RUSLE在岩溶区的应用更具有适用性；(3)为表示各种环境因子对土壤侵蚀的影响程度,提出土壤侵蚀的单位因子影响率的概念,可以用数字的大小来表征不同因子对土壤侵蚀影响程度；(4)应用多因子分析方法,结合RS和GIS技术对研究区水土流失的敏感性进行了评价,充分考虑了不同生态环境因子组合下水土流失的潜在危险性,具有较高的可信度。更多还原

【Abstract】 Soil erosion is one of the most serious global environmental problems, have serious repercussions to the global and regional ecological environment. The southwest China karst area is the world’s largest karst exposed even Area, an area of about6.2×105km2, with complex geological conditions in the region, karst is well developed, constitutes a unique "dual structure", a variety of landforms, a fragile ecological environment anti-jamming capability; karst Areas of Southwest China’s ethnic minorities and the poor are concentrated, long-term socio-economic backwardness of the local ecological environment protection and construction; fragile ecological environment and irrational human activities, making the region the situation is very serious soil erosion, and many places even the soilless flow rocky desertification situation, the local ecological environment and ecological safety of the serious challenges caused serious harm to the regional socio-economic development.As one of the Karst Areas of Southwest Guangxi region in hilly red soil and karst landform widespread soil erosion in an area of2.81km2, accounting for 11.87%of the total land area, severe soil erosion leading to a lot of land surface soil have been depleted not usein some areas has been a direct threat to the survival of the local people, facing a dual crisis of ecology and the poverty and backwardness; soil erosion brought about by sediment causing siltation of rivers, channels and reservoirs, exacerbated by the occurrence of floods and droughts; soil erosionhas become a serious constraint to economic and social sustainable development of Guangxi. The size distribution of the Guangxi Water Resources Department to explore Guangxi soil erosion and rocky desertification and soil erosion processes and the formation and evolution mechanism, scientific prediction of soil erosion, evaluation, carried out in cooperation with the Institute of Karst Geology of the Lijiang River Basin Soil Erosion Remote Sensing Research and ecological base construction projects; this study as an opportunity to select Zhaidi underground river basin study, carried out the study of soil erosion monitoring.Through the Zhaidi underground river basin soil erosion monitoring in this paper, the use of traditional monitor and improve the model to monitor a combination of methods, carried out a detailed analysis of the influencing factors of soil erosion in karst areas, the use of field monitoring and3S technology to extract the monitoring indicatorsin order to estimate watershed soil erosion, and regional soil erosion sensitivity analysis, build the karst small watershed soil erosion monitoring system.The main conclusions are as follows:(1) Through the traditional method of river sediment yield to watershed soil erosion monitoring results showed that:in2010, Zhaidi underground river basins total exports sediment output2013.6t, Basin Mainland export of sediment sediment output2922.8lt between909.2lt gap; description of the karst and of soil erosion, sediment and can not be fully brought out from the underground river exports, the reason should be part of the sediment to precipitate in the underground river; from the data calculated by the underground river basin, about30percent of the sediment left in the underground river system.(2) Calculated for the karst small watershed soil erodibility factor improved land use patterns as a basis for the calculation of the K factor; monitoring the watershed soil erosion through the RUSLE model approach, the results show that:Zhaidi underground river basin, average annual total soil loss for16655.44t, the average annual erosion modulus504.7lt/(km2·a); in accordance with the division of the karst area comprehensive soil erosion control technical standards (SL461-2009), Zhaidi underground river basin soil erosion intensity is moderate, the average annual soil erosion modulus of about karst areas of soil loss tolerance (50t/(km2·a))10times.(3) The results of the two methods quite different results based on the calculation of the sediment output is only calculated based on the RUSLE model results from12%to18%; soil erosion based on exports of the underground river, Soil erosion of Zhaidi underground river basin is mild intensity, while soil erosion estimates based on the RUSLE equation Zhaidi underground river basin soil erosion intensity is moderate; RUSLE equation-based soil erosion estimates more in line with the results of the Chinese water and soilloss and ecological safety inspection (from July2005to May2007)".(4) In the karst area of soil erosion spatial pattern analysis, the concept of "unit factor affecting the rate" to value the size of the impact of soil erosion factors, such as elevation, slope, vegetation cover, land use,extent of the effects of erosion of karst areas.(5) Through the sensitivity analysis on t Zhaidi underground river basins soil erosion, has been the most sensitive areas of the basin Mainland lower river at the exit for soil erosion, soil erosion in the area of governance and regional ecological protection should be noted that exports to the underground riverthe region’s soil and water conservation and protection of ecological environment.(6) Based on monitoring the implementation of soil erosion in the traditional monitoring and modeling, and analysis of soil erosion on Zhaidi underground river basin, from the goals, targets and implementation of three levels of soil erosion monitoring system is discussed through the land and water based on database technologyloss of monitoring information platform for the discussion of karst small watershed soil erosion monitoring system.The main innovations are as follows:(1) Karst small watershed soil erosion monitoring, obtained about30%of the sediment in the process of soil erosion (relative to the total loss of small watershed soil) to stay in the underground river system;(2) Based on land use, with the experimental method,improved the RUSLE equation soil erodibility factor K value calculated RUSLE more applicable in the karst area;(3) To represent a variety of environmental factors, the impact on soil erosion, soil erosion the unit factors affect rate concept can be used to characterize the size of the number of different factors impact on soil erosion;(4) The application of multi-factor analysis, combined with RS and GIS technology to evaluate the sensitivity of the study area soil erosion, give full consideration to the potential risk of soil erosion in the different ecological environments combination of factors, a high level of credibility.更多还原