黄河口冲淤演变及治理研究综述

Review on the Evolution and Management of the Yellow River Delta

综述了黄河口来水来沙条件的变异特点、河口演变的大小循环、河口改道后的滞后响应特征及近期河口冲淤演变的新特点,总结了以往关于黄河口演变对下游河道的影响、河口冲淤的临界水沙条件、未来河口水沙条件及河口生态等方面的研究成果。以往多数研究认为河口延伸引起的溯源淤积可影响到下游艾山或泺口河段,而对艾山以上河道是否受溯源淤积的影响争议较大,仍需深入研究不同时间尺度黄河口演变对下游河道的影响;以往研究认为维持黄河口造陆与侵蚀平衡的临界来沙量为2.74亿~4.21亿t/a,维持清水沟冲淤平衡的临界来沙量约为1.5亿t/a,后续研究需从径流、潮汐、海洋、海岸和河口河道边界条件等各因素相互作用的物理机理出发,建立统一的临界水沙量的计算方法。此外,需深入开展自然和人为因素影响下黄河口未来水沙通量的预测研究及河口生态响应研究。

This paper reviewed the changes in the water discharge and sediment load to the Yellow River delta,the major and minor cycles of delta evolution,the delayed response of delta channel to avulsions and the recent aggradation and degradation processes of the delta. It summarized the studies on the impacts of retrogressive aggradation caused by delta extension on the Lower Yellow River（ LYR）,the critical water discharge and sediment load for the balance of erosion and aggradation at the delta,the future water volume and sediment load and the ecological evolution at the delta. Most studies had argued that the channel reaches at the downstream of Aishan or Luokou stations were impacted by the retrogressive aggradation caused by delta extension. Nevertheless,consensus had not yet been reached on the issue that whether the channel reaches at the upstream of Aishan was impacted by the retrogressive aggradation or not. Thus,future study was needed to investigate the impacts of delta evolution on the LYR. Present studies have shown that the sediment load of 0.15 billion t/a is required per year to keep the erosion and aggradation balance at the Qingshuigou channel,while the critical sediment load for the balance of the erosion and accretion of the delta land is between 0.274 billion-0.421 billion t/a. A unified calculation method for the critical water and sediment conditions needs to be developed in the future based on the physical mechanics of interplays among river flow,tides,waves and the boundaries of river channel and shoreline,etc. In addition,further study should be devoted to the prediction of the future water and sediment fluxes to the delta under the impacts of natural and anthropogenic factors and the ecological response of the delta.