Estimation of Soil Erosion in Small Watershed of the Three Gorges Reservoir Region Based on GIS and RUSLE

Lingjiao pond small watershed in the Three Gorges Reservoir Region(TGRR)was chosen as the study area,quantification and analysis for each factor in the Revised Universal Soil Loss Equation(RUSLE)were carried out through Geographic Information System(GIS),Remote Sensing(RS)as well as field investigation.Soil erosion amount for Lingjiao pond small watershed in the TGRR was evaluated by RUSLE.Meanwhile,soil erosion intensity was classified according to criterion.Then the spatial distribution characteristics of soil erosion for different slope grades and different land use types were analyzed.Results indicate that the annual soil erosion amount is 208.32t/a,and the soil erosion modulus is 1987.75t/(km2·a)and the erosion intensity is classified as slight degree erosion.The moderate erosion,strong erosion and extremely strong erosion area account for 28.62% of the small watershed area,thus its soil erosion amount was account for 82.36%for the total soil erosion amount.Soil erosion is mainly occurred on slope degree between 15°and 35°.The soil erosion for 15°-25°slope grades belongs to moderate degree erosion.Soil erosion for sloping cultivated land is the most serious among different land use types.The soil erosion amount for 15°-25°sloping cultivated land accounts for 57.15% of the total soil erosion amount,indicating that sloping cultivated land is the critical area for soil and water loss in the small watershed.Compared with soil erosion modulus estimated by 137 Cs technique for sloping cultivated land as well as forestland,our results agree with the 137 Cs-estimated soil erosion modulus.Therefore,RUSLE has high accuracy and is reliable for the study area and it has good popularization value under block scale in the TGRR.