潮滩围垦对近海潮流及污染物输移的影响研究

摘要

为研究潮滩围垦对潮流和污染物输移的影响,基于二维嵌套的水动力水质模型,以通州湾为例分别模拟了不同潮滩围垦工程前后的潮流场及污染物浓度场,并用实测资料对模型进行验证,据此分析潮滩围垦作用下的流速变化和以COD为污染指标的物质输运特征.研究结果表明:通州湾围垦工程具有一定的阻水作用,且在围垦一、围垦二的堤头出现了局部挑流现象,其余海域的流速流向基本没有变化;潮滩围垦阻碍了通州湾南侧海域高浓度污染物的输移扩散,改变了该海域的污染物浓度场,且随着围垦范围的扩大,局部污染物浓度有所增加.综上所述,潮滩围垦改变了潮滩地形、水动力环境特征和污染物输移扩散能力,进而影响到潮滩的水文状况和水质环境.%To study the influence of tidal flat reclamation on tidal current and pollutant transport, we simulated the current tidal field and pollutant concentration field before and after the reclamation of Tongzhou Bay based on nested two-dimensional hydrodynamics and water quality model.The simulation results are in well accordance with the measured data, then we studied the variation characteristics of tidal current flow rate and pollutant transport using COD as pollution indicator under the influences of tidal flat reclamation.The results show that the reclamation projects have some resistance effects to the flow at Tongzhou Bay area, and the phenomenon of deflecting flow appears in the dike head of reclamation projects, while the flow velocity and direction in other sea areas don't have significant changes;the tidal flat reclamation hinders the transport of highly concentrated pollutant from the south of Tongzhou Bay, which changes the pollutant concentration field, and the pollutant concentration becomes higher with the expanding of reclamation areas.In conclusion, the tidal flat reclamation changes topography, hydrodynamic characteristics and pollutant transport capacity and influences the hydrological conditions and water quality of tidal flat.