渤海湾连片开发对湾内水沙通量的影响研究

Study on the impacts of contiguous development of Bohai Bay on the tidal current and suspended sediment fluxes

渤海湾内海岸的连续开发导致岸线、海床发生较大变化,同时影响着湾内的水沙通量。根据不同时期的遥感影像、实测地形和水文泥沙资料,统计分析了渤海湾岸线、面积和海床冲淤变化,构建了渤海潮流泥沙数学模型,模拟了1984年、2006年和2015年三个时期的水沙分布,探究了海岸连续开发对水沙分布和通量引起的累积效应。结果表明:渤海湾岸线和海湾面积变化主要发生于2005年后,与1984年相比,2020年的岸线长度增长超过185%,海湾面积减少近19%;曹妃甸港区南侧海域冲刷基本在2 m等深线以内,而近岸和港池水域基本呈现淤积状态,淤积幅度在2 m以内;海湾的连续开发利用使得湾内分潮波振幅增大、传播速度减缓,近岸海域的余流变化较为明显,南部较北部海域更甚;西北湾顶0.2 kg/m^(3)悬沙分布区域不断缩小,西南近岸0.15 kg/m^(2)悬沙分布区域向中部海域推进;悬沙通量变化与潮流通量并不完全一致,呈外海增加、近岸整体降低的变化特征,湾内向外海输移泥沙的能力减弱。

The continuous development of the inner coast of Bohai Bay has caused major changes in the coastline and seabed, affected the tidal current and suspended sediment fluxes in the bay. Based on remote sensing images, measured topography, and hydrological and sediment data in different periods, the shoreline, area, and seabed erosion and deposition changes of the Bohai Bay were analyzed. The mathematical model of tidal current and sediment in the Bohai Sea is developed to simulate the water and sediment distribution in 1984, 2006 and 2015, exploring the cumulative effect of continuous coastal development on tidal current and suspended sediment fluxes. The results show that the changes in the coastline and bay area of Bohai Bay mainly occurred after 2005. Compared with 1984, the coastline length increased by more than 185% and the bay area decreased by nearly 19% in 2020. The south side of Caofeidian port area is basically eroded within 2 m, while the coastal waters and harbor basins show siltation within 2m. The continuous development and utilization of the bay makes the amplitude of tidal wave in the bay increase and the propagation speed slow down. The residual current in the coastal waters changes more obviously than offshore areas, especially in the south than in the north. The 0.2 kg/m~3suspended sediment distribution area at the top of the northwest bay is shrinking, and the 0.15 kg/m~3suspended sediment distribution area near the southwest coast is advancing to the central sea area. The changes of the suspended sediment fluxes are not consistent with the tidal current fluxes, showing an increase in the open sea and an overall decrease in the nearshore, and the ability of the bay to transport sediment out into the sea is weakened.