前言 天然河流的河床形态是流经河床上的水流和泥沙与河床长期相互作用、不断自动调整后形成的。这种自动调整作用的最终结果在于使河流能够保持一定的平衡,这时河床断面、比降、糙率及物质组成正好具有使来自流域的泥沙能够在这样的容重和粘性的水流中输移下泄的流速。

In rivers with heavy sediment load, the river channel will adjust itself temporarilyin accordance with the variations in sediment concentration and composition for eachflood. When the amount of sediment coming from upstream increased, the result of selfadjustment is in the direction of increasing the sediment transport capacity such thatthe outgoing load from the reach will be increased too. This is the so called "the moreit comes, the more it goes" which is well known in the Lower Huang He (the YellowRiver).In this article the modified Einstein Bed-Load Function is used as a tool for thestudying of the mechanism of short-period adjustment in rivers with high concentrations.The result of analysis indicates that for Hua-Yuan-Kou reach of the Lower Huang He, thechannel bed is usually silted up for high oncoming load (and yet the concentration issmaller than 400 kg. per cu. m.) As a consequence, the bed composition will becomefiner and it is essentially through this process that the sediment transport capacity israised. However, when the on coming load surpasses 400 kg. per cu. m., the channel will bedeeply eroded instead. In this case, the change in physical properties of the flow due tothe presence of high sediment concentration and the adjustment in channel shape are thetwo major factors in raising the sediment transport capacity.