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2002 年 5 月 21 日至 6 月 2 日间, 利用 ADP 等仪器对重庆至宜昌段三峡河床进行了纵剖面流速及地形的测试. 工作期间的流量小于 15000 m3/s. 结果表明重庆至万县段流速与河宽成正比, 最高流速达3.0~4.0 m/s, 一般出现在河宽大于 1000 m, 水深小于20 m, 由巨砾和卵石滩组成的碛滩部位, 过水断面面积很小. 相反, 低流速出现在水深较大的河床部位, 河宽小于500 m, 河谷呈准“U”字型, 过水断面面积较大. 万县往下至奉节河段, 最大流速基本都出现在水深大于 50 m 的峡谷河床部位, 流速大于上部碛滩河段, 河宽较小(小于 600 米), 河床呈“V”字型, 过水断面面积较小. 奉节至秭归河段, 水深大的部位, 河宽小(小于 500 m), 河床呈“W”字型, 过水断面面积较大, 流速变小. 研究表明过水断面控制着流速分布. 秭归~葛洲坝之间出现缓流区(包括西陵峡), 流速小于 1.0 m/s, 为葛洲坝建坝后效应. 另外, 葛洲坝建坝 25 年来河床明显淤积, 库区河床淤积抬高达 20 m, 并且出现水面壅水现象, 向上游可延伸 150 km. 坝下底床出现 15~20 m 的冲刷现象.
Between May 21 and June 2, 2002, the longitudinal flow velocity and topography of the Three Gorges riverbed from Chongqing to Yichang were measured by means of ADP and other instruments.The flow during operation was less than 15000 m3 / s.The results showed that from Chongqing to Wanxian The velocity of the section is proportional to the width of the river, and the maximum velocity is 3.0-4.0 m / s. Generally it occurs in a moraine beach composed of boulders and pebbles with a river width of more than 1000 m and a water depth of less than 20 m. On the contrary, the low flow rate appeared in the part of the river with larger water depth, the river width was less than 500 m, the river valley was quasi “U”, and the cross section area was larger. In the part of canyon where the water depth is more than 50 m, the flow velocity is greater than that of the upper moraine bank, the river width is smaller (less than 600 meters), the riverbed is “V” and the cross section area is small. Large area, the river width is small (less than 500 m), the riverbed is “W” shape, the cross section of the water area is larger, the velocity of flow is smaller.Research shows that the cross section control the flow velocity distribution. District (including Xiling Gorge), the flow rate is less than 1.0 m / s, for the Gezhouba Dam In addition, the riverbed of Gezhouba Dam has been obviously silted in the past 25 years, and the siltation in the riverbed of the reservoir area has risen up to 20m, and the phenomenon of water splashing can occur, extending up to 150km upstream and erosion of 15-20m in the bottom of the dam.