Abstract: In Three Gorges reservoir area, concentrated rainstorm with short duration and high intensity is an important factor causing soil erosion. In the aim of investigating rainfall infiltration and characteristics of runoff and sediment yield in small watershed of Three Gorges reservoir area, we establish a miniature model for the area and simulate rainfall in the presence of different rainfall intensities(60, 90, 120 mm/h) to analyze rainfall infiltration of small watershed erosion and runoff process characteristics. Research results show that : 1) runoff yield increases with rainfall intensity, and the impact of rainfall intensity on increase of infiltration is effective only within a certain range; 2) infiltration rate and runoff yield intensity gradually tend to be stable, infiltration rate is in agreement with law of logarithmic function, whereas runoff yield intensity varies according to power function; 3) relationship between cumulative sediment yield and cumulative runoff in the three rainfalls can be fitted by power function, and there is a good linear relationship between sediment concentration and erosion yield. The results provide important scientific basis for the prevention and control of soil and water loss in the area.

Key words: Three Gorges reservoir area, rainfall simulation, small watershed, rainfall infiltration, soil erosion