Soil Erosion Assessment In Lvergouu Watershed, Tianshui City

Soil erosion has become China’s most serious environmental problems, and China is also one of the most serious soil erosion regions in the world, especially in the Loess Plateau, where the total area of soil erosion accounted for62%of the total drainage area. The Lvergou watershed this paper studied is a first class branch gully by the right bank of Jihe River which is a tributary of the Weihe River. It is located in the Loess Plateau which is the most serious soil erosion regions. The watershed was studied mostly in sediment and hydrology in the past, and also had few systematic soil erosion assessments based on GIS and RS. Therefore, this article utilized revised universal soil loss equation (RUSLE) studied more mature in the international to make qualitative, quantitative and located soil erosion assessment, and provide a reference in data and method for water and soil conservation in this watershed. This paper used ArcGIS, ERDAS and other software to take some processing such as interpolation, interpretation and calculation for rainfall data, image data and soil data for2010, and acquired soil erosion modulus, soil erosion intensity and soil erosion intensity maps. Detailed evaluation and analysis was made for each factor’s selection and treatment. And finally the distribution characteristics of soil erosion intensity in the Lvergou watershed ware got:in this watershed, moderate and below erosion accounts for62.61%, mainly concentrated in the ridge, the main channel and the higher vegetation coverage regions; severe erosion is21.91%, mainly distributed in lower vegetation coverage, larger slope and slope length areas. Rainfall erosivity factor, slope factor and slope length factor have greater impact on the region’s soil erosion intensity while soil erosion modulus performance low sensitivity on soil erodibility factor. Also soil and water conservation project in the basin in recent years to curb soil erosion has player a certain effect.