The Spatio-temporal Pattern Change Of Eroded Landscape In Degraded Red Soil Region

A small watershed as the basic unit for integrated watershed management is being recognized and introduced by more and more countries. In recent 20 years, due to the rapid development of socioeconomic situation, large area of land is destroyed by exploitation projects, therefore, new soil erosion occurs, and the complexity and diversity of soil erosion presents. Based on the topographic contour map (scale=1:10000) and SPOT5 image data, supported by ArcGIS9.0,ArcView3.3,ERDAS IMAGINE8.7,ENVI4.2, with their respective processing technologies, take the landscape pattern analysis, investigation and practice as the research methods, the development and application of high spatial resolution data in the small watershed of Zhuxi River were studied. The results indicated that:1) The availability of high resolution data, including those of topography, hydrography, soil erosion, land use and so on, for watersheds, is an increasing concern. The case study can serve as a model for building high resolution spatial data and provide a means to solicit detailed information for decision marking in the planning, management or monitoring of watersheds. Issues about error minimization, data quality control, and how to improve data accuracy, are also identified.2) The structure of quantity and spatial distribution of soil erosion was analyzed in the study region. The soil erosion status has been improving, particularly since the 2000s, with the erosion rate showing an evident decline over the past 7 years. The slight and light erosion was doubly increased while the moderate and more serious erosion were decreased. The Soil Erosion Intensity Index (SEII) and the Soil Erosion Intensity Coefficient (SEIC) in 2007 were lower than that in 1999 under different terrain gradients such as elevation, slope and aspect.3) The spatio-temporal pattern of eroded landscape in the small watershed of Zhuxi River obviously changed, too. The homogenization of eroded landscape was ascensive. The compositions of eroded landscape in different slope grades were quite different, and the variations from 1999 to 2007 were also quite different. Human activity is the main driving factor for the dynamic changes of spatial pattern of eroded landscape in this study region.4) Resorting to the powerful function of RegionManager5.5, and the field survey, the soil and water conservation monitoring in the small watershed of Youwuzhen River in 2007 were carried out.