硕士论文摘要-基于GIS的全国典型水蚀区侵蚀后果危险度评价研究

摘要
水土流失的研究和实践表明，仅仅依靠水土流失强度不能够全面反映某地区的水土流失严重性和危险程度，同时也不能对未来的趋势做出良好的判断，开展全国水土流失危险度研究，可以为客观分析和评价区域水土流失程度及其变化趋势提供基础数据，为国家水土保持生态建设决策提供科学依据。

本研究是在2005年由水利部、中国科学院和中国工程院联合开展的“中国水土流失与生态安全综合科学考察”活动的背景下开展。

作为本次考察活动水土流失状况与基础数据集成专题研究组的一个子专题，研究成果将直接为评价全国水土流失状况提供基础数据。

根据我国土壤侵蚀类型分区，将全国水蚀区划分为东北黑土区、北方土石山区、西北黄土区、长江上游及西南诸河流域区、南方红壤区、西南石漠区和北方水蚀风蚀交错区等7个类型区，在每个类型区内，进行水土流失类型二级分区，共划分30个样区，对每个样区选取典型地段，进行水土流失危险度分析，进而反映全国的水土流失危险度状况。

在每个样区的典型地段选取一幅1：10000地形图作为调查单元，野外实地调查获取土地利用、植被盖度和有效土层厚度等数据，利用地形图矢量化生成DEM获取的地形坡度；遵照水利技术标准《土壤侵蚀分类分级标准》（SL 196—96）规定的水力侵蚀分级标准，利用GIS软件将土地利用类型、植被盖度、地面坡度等水土流失因子数据进行空间叠加，分析评价每个调查单元每个地块（图斑）的水土流失强度和侵蚀后果危险度状况，综合分析评估各样区的水土流失危险度状况。

通过5个类型区、20个样区的水蚀强度和危险度分析可知：（1）每个样区存在水土流失危险性的土地面积（指轻险型及轻险型以上面积）均比较大，大部分样区的面积占到本区土地总面积的一半以上；（2）5个类型区中，西南石漠区存在水土流失危险性的土地面积所占比例最大，占类型区总面积的82.6%，北方土石山区、西北黄土区、长江上游及西南诸河流域区和南方红壤区4个类型区的比例相当，为60％左右；（3）在超过50％的轻险型以上的土地中，除西北黄土区外，危险型及其以上危险程度的土地在各类型区中均占到一定比例，北方土石山区、南方红壤区、西南石漠区、长江上游及西南诸河流域区的危险型及其以上危险程度的比例分别占到26.1％、6.73％、43.03％和10.72％。

本研究，在全国水蚀后果危险度分析评价抽样调查区划、利用GIS技术评价水蚀
后果危险度方法等研究方面，具有一定的独创性。

同时，第一次按照国家技术标准，进行了全国水蚀后果危险度评价，为“中国水土流失与生态安全综合科学考察”提供了基础数据，为国家生态建设决策提供了科学依据。

关键词：中国水土流失侵蚀后果危险度地理信息系统抽样调查
ABSTRACT
Potential Hazard Degree Evaluation of Representative Water
Erosion Region in China Based on GIS
Master Candiadate: Luo Zhidong
(Specialty of Forest Management)
Directed by Associate Professor Shi Mingchang,Senior Engineer Li Zhiguang
ABSTRACT
The study and practice on soil and water have manifested that it can’t reflect the serious and hazard of soil and water erosion in its entirety only depend on soil and water erosion intension. At the same time, it can’t make a good evaluation of tendency in future. Developing study on countrywide hazard degree of soil and water erosion can provide basic data for analyzing and evaluating the degree and tendency of region soil and water erosion objectively, science basis for national Eco-construction of soil and water conservation decision-making. This study is developed under the background of integrated science review of Chinese soil and water erosion and ecological safe, which was developed by Ministry of Water Resources, Chinese Academy of Sciences and Chinese Academy of Engineering. As a sub-topic of the subject group who study soil and water erosion and basic data integration, its result will provide basic data for evaluating the status of countrywide soil and water erosion directly.
According to the subarea of soil erosion type in our country, water erosion region is caved up into seven type regions, which contains Black Soil Region in Northeastern China, Soil Stone Mountain Region in Northern China, Loess Plateau Region in Northwestern China, Upper Reaches of Yangtze River and Reaches of Southwest River Region, Red Soil Region in Southern China, Rocky desertification Region in Southwestern China, Wind-Water Interaction Region in Northern China, and so on. In each type region, soil and water erosion type is divided secondly into 30 typical regions. We select typical land sections in each typical region, analyze the hazard degree of soil and water erosion, and reflect the hazard degree status of countrywide soil and water erosion. In each typical land section of typical regions, we select a breadth of relief map in scale of 1 to 10000 as a survey cell, get data of land use, vegetation cover, effective thickness of soil layer through field survey, get terrain grade information through vectoring the relief maps, then complied the water erosion classification standard of water resources technical standard《soil erosion classification》（SL 196-96), overlay the layers of land use, vegetation cover, terrain grade and other soil and water erosion factors with GIS software, analyze and evaluate the intension and hazard degree of soil and water erosion of each survey cell and typical region.
Through the analysis of water erosion intension and hazard degree of the five regions and 20 typical regions, we can reach conclusions as following:
（1）The area of land which exists soil and water erosion hazard in each typical region is large. In a。