河床下切对磨刀门水道咸潮上溯的影响
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摘要
为研究河床下切对磨刀门水道咸潮上溯的影响,基于珠江河口三维数值模型,结合珠江三角洲网河区河床演变情况,设置合理算例进行了数值模拟计算,并对计算结果从纵向、垂向和时间三个维度进行分析。结果表明,不同潮汐条件下河床下切对磨刀门水道咸潮上溯的影响结果有所差异,河床下切有利于盐度垂向分层和盐水楔活动,相对而言,河床下切对小潮期咸潮灾害强度加剧作用更为明显,其次为中潮期,大潮期影响相对较小。
In order to study the hydrodynamics of saltwater intrusion in the Modaomen River Channel and its response to the riverbed degradation,based on three-dimensional numerical model for the Pearl River Estuary,case studies were carried out according to the evolution of riverbed.The dynamic process of saltwater intrusion at the longitudinal,vertical direction and time domain was analyzed according to simulation results from different cases.The results indicate that riverbed degradation can obviously lead to the enhancement of saltwater intrusion and its contribution was different during different tidal period.During neap tide,the density-reduced current plays the key role and high-salinity water continuously intrudes upstream with a saline wedge.As a result,riverbed degradation leads to an obviously increase of salinity at the bottom layer.With the increase of tidal range during the following middle tide,riverbed degradation leads to the increase of salinity at both surface and bottom layer.
In order to study the hydrodynamics of saltwater intrusion in the Modaomen River Channel and its response to the riverbed degradation,based on three-dimensional numerical model for the Pearl River Estuary,case studies were carried out according to the evolution of riverbed.The dynamic process of saltwater intrusion at the longitudinal,vertical direction and time domain was analyzed according to simulation results from different cases.The results indicate that riverbed degradation can obviously lead to the enhancement of saltwater intrusion and its contribution was different during different tidal period.During neap tide,the density-reduced current plays the key role and high-salinity water continuously intrudes upstream with a saline wedge.As a result,riverbed degradation leads to an obviously increase of salinity at the bottom layer.With the increase of tidal range during the following middle tide,riverbed degradation leads to the increase of salinity at both surface and bottom layer.
引文
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[2]陈文龙,邹华志,董延军.磨刀门水道咸潮上溯动力特性分析[J].水科学进展,2014,25(5):713-723.
[3]孔兰,陈晓宏.珠江口咸潮影响因素分析[J].水资源保护,2015,31(6):94-97,134.
[4]张蔚,严以新,诸裕良,等.人工采砂及航道整治对珠江三角洲水流动力条件的影响[J].水利学报,2008,39(9):1 098-1 104.
[5]李春初.珠江河口咸潮问题之我见[J].热带地理,2013,33(4):496-499.
[6]包芸,刘杰斌,任杰,等.磨刀门水道盐水强烈上溯规律和动力机制研究[J].中国科学(G辑),2009,39(10):1 527-1 534.