GIS and Remote Sensing in Hydrology, Water Resources and Environment (Proceedings of ICGRHWE held at the Three Gorges Dam, China, September 2003). IAHS Publ. 289, 2004, 101-106

Abstract To calculate soil erosion in a catchment based on land-units is a new and important method for the estimation of the impact of soil and water conservation measures. In this research, the traditional technology of a grid based flow network is improved according to the role of soil erosion, for the loess plateau of China. A land-unit based runoff and sediment flow network model was developed to simulate the flow process through a complicated geographical surface in small basins. The flow network between land-units is calculated and three major parameters for the soil erosion model are acquired: water and sediment flow order between land-units, the spatial distribution of the conflux amount among land-units and the slope length of each land-unit. The soil erosion model is connected with the land-unit flow network, and the parameters for each land-unit such as soil type, slope, elevation, cultivation measures, landform position, slope length, etc., are automatically transferred from the land-unit file to the soil erosion model. Whole basin simulation of soil erosion was carried out; the results can be put back into a GIS for spatial analysis and display.

Keywords land-unit; runoff and sediment flow networks; soil erosion