Simulation on the spatial-temporal changes of soil erosion in the Three Gorges Reservoir Area between the pre- and post-storage periods

Abstract

利用三峡库区水土流失预测模型和250m的MODIS-NDVI数据,模拟三峡库区蓄水运行前后水土流失时空变化,结果表明:三峡库区2000-2008年水土流失波动较大,总体上水土流失面积、总量和强度都呈减弱趋势,2006-2008年年均水土流失总量和面积分别比2000-2002年减少4.10×10⁶t和1129.6km²;强度、极强度和剧烈等级水土流失主要分布在秭归、巫山、巫溪、石柱和武隆等坡度15°以上的林地和耕地,水土流失减弱主要集中分布在奉节、云阳、万州和忠县等坡度10°以上的耕地和林地;库区水土流失时空变化主要受降水强度与分布、移民与蓄水运行和生态工程实施影响.库区水土流失总体虽然呈好转趋势,但库区水土保持与治理工作还需进一步加强,尤其是对库首秭归、兴山和巴东及库中武隆等区域,需严禁坡耕地退耕还林反弹.;Spatial and temporal changes of soil erosion in the Three Gorges Reservoir Area(TGKA) between the pre- and post-storage periods were simulated with the soil erosion model using 250m MODIS-NDVI remote sensing data. Hie results showed that:Total amount, area and intensity of soil erosion were all generally at the reducing trends during 2000-2008 with great fluctuations. The average annual total amount and area of soil erosion decreased by 4.10×10⁶t and 1129.6km² from 2000-2002 to 2006-2008, respectively. The high, very-high and severe types of soil erosion mainly centralized at the forest and cropland above 15° in Zigui, Wushan, Wuxi, Shizhu and Wulong, and soil erosion intensity with lower levels from 2000-2002 to 2006-2008 mainly centralized at the cropland and forest above 10° in Fengjie, Yunyang, Wanzhou and Zhongxian. Spatial and temporal changes of soil erosion in the TGRA were mainly influenced by rainfall intensity and distribution, the resettlement and the operation of the Three Goi^es Project, and the implementation of a series of ecological projects. Although the soil erosion in the TGRA was reduced, the management of soil and water conservation in the TGRA need to be further strenghthened, especially in the area of Zigui, Xingshan, Badong and Wulong.