Simulation of the spatial differentiation and dynamic variation of watershed erosion intensity

The spatial differentiation of erosion intensity is one of important part of the research on sediment source of small watershed. Based on simulation experiments of small watershed model, using artificial simulation rainfall, high precise photogrammetry and GIS technology, the erosion intensity of different parts of watershed model and dynamic variation of erosion intensity were studied. Results show that the development process of watershed model of twenty-five simulation rainfalls is divided into early phase, active phase and stable phase according to relative erosion modulus. Erosion intensity of valleys is much more than that of slopes during the whole development process of watershed model. During the early phase and previous period of active phase, the erosion intensity of chief gully is more than that of branch gullies; the erosion intensity of upside part of watershed model is more than that of middle and downside part of watershed model. During late active phase, the erosion intensity of chief gully is less than that of branch gullies; erosion intensities of middle and downside part of watershed model increase rapidly and reach peak value. During stable phase, the erosion intensity variation of chief gully and branch gullies tends to synchronization, the erosion intensity of upside part of watershed model is higher than that of middle and downside part. The spatial and temporal distribution characteristics of erosion intensity is significant for the comprehensive controlling of soil erosion of small watershed.