The Study On Spatial Variation Of Head Erosion In The Lishan Mts-Hengling Hills-Bailu Loess Tableland

The head erosion is a major erosion on gully landform development and the most active gully erosion in our country at present, which is in a close relation to soil erosion and sediment yield and landform development. There are loess tableland, loess hills, rivers and Earth-rock low mountains in the Lishan Mts-Hengling hills-Bailu loess tableland, where the terrain is complex. The head erosion is very strong in this gully area and also the characteristics of head erosion on different types of landforms are not the same. Therefore, further research to quantify features of head erosion and regional characteristics in this area is not only helps to reveal the characteristics of gully evolution and development, but also has a great value on soil and water conservation, protection and utilization of land resources in the area.This study summarized the previous research results and based on the previous experience. According to the relevant subject knowledge such as geomorphology, hydrology and spatial statistics, integrating the digital terrain analysis, geostatistical analysis and remote sensing image interpretation which are laboratory experiment and other methods that dominated by the GIS technology, combining the fieldwork on gully head, and also using the ARCGIS software as the main technology platforms, the research analyzed the regional difference and spatial variation of head erosion in the Lishan Mts-Hengling hills-Bailu loess tableland.This paper firstly introduced the relevant theory of gully head, through combining the geomorphological features, the author made a definition of its scope, and further developed the extraction methods that based on the DEM data in 5m resolution, and then conducted an extraction experiment of the gully head that obtained a better result. What’s more, four quantitative indicators were chosen to characterize the intensity, residual volume and potency of the head erosion, that is, the frequency of gully head is manifested the erosion intensity, the degree of approximation is represented the residual volume, relative elevation and average gradient of gully head are characterized the potency of the head erosion.Through analyzed the four indicators above that extracted in the experimental sample area and found that the selected quantitative indicators could well reflect the head erosion features of different landforms in the study area. On this basis, after studying on spatial variation of quantitative indicators that 28 experimental sample areas evenly distributed in the Lishan Mts-Hengling hills-Bailu loess tableland, and found that head erosion had a certain distribution rule:the frequency of gully head tend to increase from south to north in the study area; meanwhile, the degree of approximation showed a decreasing trend; the trend of these two indicators correspond to the different landscape features and characteristics of head erosion in the study area. The relative elevation and average gradient of gully head were showed a distribution rule that the Lishan Mts and Bailu loess tableland are slightly higher, the middle region that Hengling hills is slightly lower, which is consistent with the different landscape features and characteristics of head erosion in the study area.This study is an innovation that to extract on gully head and quantitative research in the head erosion, it has a certain reference significance for further research on landform development and the head erosion even though there are still some deficiencies.