黄河流域洪水对入海泥沙通量的影响

利用1950～1985年大样本洪水资料,研究了黄河流域洪水过程中三黑小所控制的流域水沙条件与入海泥沙通量和通量系数的关系,分析了泥沙通量与流域水量、沙量和平均流量的关系。在三黑小沙量与入海泥沙通量的关系中,从量上看,黄河下游河道具有“多来多排”的特性;从比例上看,具有“多来多淤”的特性。不同来源区洪水对泥沙通量和通量系数具有不同的影响,平均每场洪水泥沙通量按大小排序依次是:多沙粗沙区、下少沙区、上少沙区和多沙细沙区。通量系数按大小排序依次是:下少沙区、上少沙区、多沙细沙区和多沙粗沙区。

Effects of the flood events in the Yellow River basin on the sediment flux to the sea

Based on the data of 278 flood events of the Yellow River from 1950 to 1985, this paper reveals the relationships among the sediment fluxes and the conditions of water and sediment of the Yellow River at Sanheixiao, and the impacts of flood events from different source areas on sediment flux and flux ratio. From the aspect of the sediment amount, the more the sediment comes from the basin during a flood event, the more the sediment fluxes go to the sea. And from the aspect of sediment silt proportion, the more the coming sediment amount, the smaller the sediment flux ratio. Given coming sediment conditions, the sediment fluxes of flood events with lower sediment concentration are larger than that of higher sediment concentration, and the higher the coming sediment load, the more obvious of this phenomena. And given sediment flux, the flood event with higher sediment concentration has the larger amount of coming sediment but the lower flux ratio, which means there has more sediment silted in the channel. The flood events from different source areas have different impacts on sediment flux and flux ratio. The flood events from the coarser sediment_producing area have the most important impact on sediment flux, and when the floods come from this area, the more the quantity of sediment, the lower the flux ratio. When the floods come from the lower sediment_producing area, the more the amount of sediment, the higher the flux ratio. The sediment flux of flood events becomes lower in the order from the coarser sediment producing area, the lower area, and the upper area, to the finer area; and the flux ratio of flood event becomes lower in the order from the lower sediment producing area, the upper area, and the finer area, to the coarser area.