黄河口现行入海流路的摆动规律及其趋势研究

Evolution Process and Trend of Current Flow Paths into Sea in the Huanghe Estuary

为研究多沙河流入海流路的摆动规律及其变化趋势,根据1976~2015年黄河口实测地形资料分析黄河口改道清水沟后入海流路的摆动过程。结果表明:行河河道整体上不断淤积延伸,受径流与海洋动力的综合作用;不行河河道呈侵蚀状态,主要受海洋动力的影响;行河河道的淤积存在洪枯季变化,年内洪季淤积幅度大于枯季,自然出汊的时机一般发生在汛期。1996年出汊以后,年入海水量较之前减少42%,年入海沙量减少78%,而河道的平均淤积速率降低了81%,入海沙量的变化与河道淤积长度明显相关;预测入海流路的出汊摆动频率及幅度将会降低,未来清水沟流路的出汊摆动延伸在1976年的入海流路与目前的入海流路之间。

In order to study evolution processes of riverine flow paths in high-sediment-load estuaries,we conducts a case study of the evolution of current Qingshuigou flow path in Huanghe Estuary based on the measured topographic data from 1976 to 2015.The results show that the deposition patterns of current flow paths vary between flood and dry seasons.The deposition rates in flood seasons are larger than that in dry seasons and the avulsions of flow paths always occur in flood periods.Current flow paths deposits and extends,which is controlled by runoffs and ocean hydrodynamics.The old flow paths are eroded and dominated by ocean power.The runoffs and sediment into sea reduce by 42%and 78%after 1996,respectively.As a result,the averaged deposition rate reduces by 81%.The avulsion rate of the flow path into sea is also decreased.Our study suggests that Qingshuigou flow path will wander and extend between the flow path in 1976 and the present flow path.