Using methods such as RUSLE, investigation reduction and submergence analysis, the quantity of average annual intercepted silt and the spatial distribution of soil erosion in Huangtuwa watershed are analyzed. The results show that the average soil erosion modulus of the silt arrester and upstream hilly and gully erosion region is 8 116.14 t/(km2·a) during the period of 2000—2010, which is 7 714.73 t/(km2·a) simulated by RUSLE, and the simulation accuracy is 95% by comparing the calculated and measured values. In the watershed, erosion areas with strong, very strong and violent eroded, account for 53.18% of the watershed area, which indicate watershed erosion modulus is relatively high. Loess sediments lying within the natural dam come mainly from beam hilly farming area, inter-gully and dam edge whose slope is greater than 15°.The erosion modulus is decreased by 26.15% under the artificial water and soil conservation condition. Natural check dam can interception all sediments in the control area, and the contribution rate to the sediment interception in Huangtuwa watershed could be up to 77%, and the effects of the soil and water conservation are apparent. The sedimentation volume of Huangtuwa natural check dam is about 2.303×106 m3.

Huangtuwa watershed; natural check dam; revised universal soil loss equation(RUSLE); soil erosion modulus; soil and water conservation