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一、长江流域的水土流失现状 长江是我国第一大河,干流全长约6300km,流域面积180万km~2,遍及我国18个省、市、自治区。宜昌以上为上游,长4504km,面积100万km~2;宜昌至湖口为中游,长948km,面积68万km~2;湖口以下为下游,长830km,面积12万km~2。流域内地貌类型以山地、丘陵为主。山地高原约占60％,主要分布在流域西部和边缘分水岭地带;丘陵、盆地约占25％,主要分布于四川盆地,湘、赣两省中部及巢湖水系中游地带;平原和水面占15％,主要分布于川西、
I. Current Status of Soil and Water Loss in the Yangtze River Basin The Yangtze River is the largest river in China. The total length of the main stream is about 6,300km and the drainage area is 1.8 million km ~ 2, covering 18 provinces, municipalities and autonomous regions in our country. Yichang is above the upper reaches, with a length of 4504km and an area of 1 million km2. The middle reaches of Yichang-Hukou are 948km long and 680,000 km2 in area. The lower reaches are 830 km downstream and 120,000 km2. The landscape types in the basin are mainly mountains and hills. About 60% of the mountainous plateau is mainly distributed in the western and marginal watershed watershed watersheds; hilly, about 25% of the basin, mainly in the Sichuan Basin, Hunan and Jiangxi provinces and the middle reaches of the Chaohu Lake; plain and water 15% Mainly located in western Sichuan,