基于地貌演进背景的流域自然与人为侵蚀定量评估——以鲁中南山地为例

Quantitative Assessment on Natural and Human Erosion Based on the Study of Geomorphologic Evolution——A Case Study of Luzhongnan Mountainous Area, Shandong Province

在GIS软件的支持下,计算了鲁中南山地及其各流域的高程积分并判定了其地貌侵蚀阶段,对鲁中南山地第四纪平均侵蚀量作了初步估算。通过侵蚀指数、自然侵蚀指数、人为侵蚀指数等指标的构建,计算了鲁中南山地各流域水土流失的自然侵蚀背景,进而得出人为侵蚀强度的流域差异。研究表明,鲁中南山地整体的自然侵蚀速率约为0.17 mm/a,大致相当于实际侵蚀的1/4,人为侵蚀强度较大;自然侵蚀强烈的流域主要分布在研究区北部,而人为侵蚀严重的流域主要分布在研究区东南部。提出了地貌演进背景下水土流失自然(地貌)侵蚀与人为侵蚀定量评估的技术方案,对鲁中南山地水土保持工作的政策措施提出了建议。

Soil erosion is related not only to the unreasonable use of land surface, but also to the natural process of landform evolution. It is the basis for rational soil conservation policy and project to distinguish the natural erosion and man-made erosion （human erosion） The mountainous area in central and southern Shandong province （Luzhongnan mountainous area）, more than 33000 square kilometers, is the severest area of soil erosion in the province. Taking Luzhongnan mountainous area as a typical case and based on the study of regional geomorphologic evolution, the technical method on quantitative assessment on natural and human erosion is proposed in this paper. Aided by GIS software of MapInfo and ArcView, the altitude-area integral and geomorphologic evolution stage of each catchment in Luzhongnan mountainous area are all determined. The erosion amount per year during Quaternary is also estimated. By construction of Erosion Index, Natural Erosion Index and Human Erosion Index, the spatial patterns of natural erosion background and human erosion intensity are revealed. It is indicated that the natural erosion velocity is 0.17mm/a and the natural erosion intensity is only 1/3 of that of human erosion in the research area. The natural erosion is more intensive in the catchments northern of the research area while the human erosion is more intensive in the southeastern catchments. Under the circumstance of shortage of manpower and financial support, catchments that human erosion plays a more important role should be conserved over all other catchments. So, as Luzhongnan mountainous area is concerned, the catchments in the southeast of the research, named as East Wenhe River, Chaiwenhe River, Benghe River and the upper reaches of Yihe River should be conserved above all.