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为得到三峡水库实际运行后库区泥沙的淤积糙率,基于三峡水库运行10余年库区实测淤积资料、日均来流量与水位序列,采用一维水流模型推算了三峡水库正常蓄水运行以来库区沿程的综合糙率。结果表明,常年回水区峡谷段淤积较少,糙率随流量、运行时间变化较小,糙率相对较大;常年回水区宽谷段泥沙在主槽落淤后床面阻力减小,糙率逐年降低;常年回水区弯曲分汊段泥沙淤积严重,糙率逐年减小;变动回水段天然河道特性起控制作用,糙率相对稳定。同一洪水流量情况下,随运行时间推移和淤积发展,糙率总体减小。常年回水区糙率的降低值明显大于变动回水区糙率的降低值。三峡水库淤积过渡期糙率与河道部位、断面形态、河道形态等参数均存在一定关系。研究成果为三峡水库淤积与糙率的关系研究奠定了基础。
In order to get siltation roughness of sediment in the Three Gorges Reservoir after actual operation, based on the measured siltation data, average daily flow and water level sequence in the Three Gorges Reservoir over a period of more than 10 years, a one-dimensional flow model was used to calculate the normal water storage operation of the Three Gorges Reservoir Comprehensive roughness of the reservoir area along the way. The results show that the silt accumulation in the canyon section of perennial backwaters is less, the roughness changes little with the flow and operating time, and the roughness is relatively large. , The roughness decreases year by year; the sediment deposition in the curved sub-section of perennial backwater area is serious, and the roughness decreases year by year; natural channel characteristics of fluctuating backwater section play a controlling role, and the roughness is relatively stable. With the same flood flow rate, the roughness decreases with the passage of time and deposition. The reduction of the roughness of perennial backwater area is obviously larger than the decrease of the roughness of the backwater area. The roughness of transitional period of Three Gorges Reservoir has some relations with the parameters such as the part of the river channel, the shape of the section and the shape of the river. The research results laid the foundation for the study of the relationship between siltation and roughness of the Three Gorges Reservoir.