近十年来渤海湾围填海工程对渤海湾水交换的影响

IMPACT OF RECLAMATION ON WATER EXCHANGE IN BOHAI BAY IN RECENT DECADE

近十年来我国海岸带地区快速城市化,对土地的需求持续高涨,导致沿海地区围海造地现象愈演愈烈,海湾纳潮海域面积持续萎缩,对海湾的水交换带来了较大压力。为此,选取我国海岸带快速城市化的典型区域——渤海湾为例,研究近十年来渤海湾海岸带城市化对渤海湾水交换的影响。基于国际流行的MIKE3水动力模型耦合粒子追踪模块,应用2000年和2010年两个典型年份的渤海湾岸线资料,分别计算了2000年和2010年渤海湾环流系统及其驱动下的水质点运移规律和变化特征。研究将渤海湾划分为8个区块,定量化研究和对比了近十年来由于渤海湾持续围填海导致的海湾水存留时间和不同区块水交换能力的变化。结果表明,随着近十年来渤海湾沿岸快速城市化产生的岸线变化,导致湾内环流涡旋增多,决定湾内水交换的流场结构发生了显著变化,导致各区块的水交换能力和平均水存留时间不仅存在较大差异,而且发生了显著的变化。与2000年相比,2010年天津港、黄骅港和曹妃甸港区海域的平均水存留时间明显增加,水交换率下降,对区域水质的改善十分不利。

Coastal reclamation has been increasing due to rapid urbanization in coastal zone in China in recent decade, resulting in continuous tidal prism decrease and large pressure on water exchange in coastal bays. To study the effect of coastal zone urbanization on water exchange in recent decade, Bohai Bay in North China was taken as an example. The MIKE 3 hydrodynamic model coupled with particle tracing module was applied in Bohai Bay with 2000 and 2010 coastline data. For detail understanding of in-bay water exchange, Bohai Bay was divided into eight parts in natural and anthropological features. Changes in average residence time, water exchange pattern, and water movement dynamics in the eight parts were calculated. Results reveal significant change in water current regime of the bay in hydrodynamics due to coastline alteration. Modifications in the bay water exchange and average residence time have been changed remarkably, especially in Tianjin Harbor, Huanghua Harbor, and Caofeidian Harbor in 2010 as compared to the situation in 2000, which is detrimental to the regional water quality improvement and shall be taken with effective countermeasures.