黄河三角洲工程防护区海床侵蚀过程与不稳定性评估

Seabed Erosion Process and Instability Assessment in the Engineering Protection Zone of the Yellow River Delta

近年来受入海水沙减少、海岸带高强度开发和海洋动力作用等的影响,黄河三角洲近岸海床侵蚀凸显。基于实测地形和波浪资料,研究了黄河三角洲工程防护区海床侵蚀过程及稳定性变化。工程防护区海床侵蚀主要分布在近岸10 km内,2007-2015年距岸8 km区域内表现强烈侵蚀,堤前海床较2000-2007年时段侵蚀量增大,海床侵蚀向岸加剧。随着现行河口沙嘴的淤积延伸和孤东浅水区的不断侵蚀,孤东南大堤外海逐渐形成了"近岸区深,远岸区浅"的反剖面形态。随着工程防护区近岸持续侵蚀,等深线不断向岸移动,堤前海床不稳定性逐渐加剧,2015年84.20%的堤前海床处于强或极强不稳定状态。本研究可为新形势下黄河三角洲综合治理提供科学依据。

The seabed erosion in the coastal area of the Yellow River Delta has become more prominent due to the influence of decrease in water and sediment entering into the sea,the high intensity development of coastal zone and the ocean dynamical action in recent years.The seabed erosion process and the stability change in the engineering protection zone of the Yellow River Delta are studied based on the measured topographic and wave data.The seabed erosion in the engineering protection zone is mainly distributed within 10 km near shore.From 2007 to 2015,strong erosion occurred mainly within the area 8 km away from the shore.Compared with that in the period from 2000 to 2007 the erosion amount of the seabed in front of the dike increased,and the seabed was eroded intensively toward the coast.With the extension of accretion at the current estuary sand mouth and the continuous erosion in the shallow area of the Gudong dike,a reverse profile of“deep nearshore and shallow offshore”was gradually formed in the offshore waters of the southern Gudong dike.With the continuous erosion of nearshore in the engineering protection zone,the contour lines shifted continuously toward the coast and the instability of the seabed in front of the dike intensified gradually.In 2015,84.20%of the seabed in front of the dike was in a strong or extremely strong unstable state.This study can provide a scientific basis for the comprehensive management of the Yellow River Delta in the new situation.