东江咸潮上溯特征及盐度输运机理浅析

Analysis of saltwater intrusion characteristics and salinity transport mechanism in the Dongjiang River

针对东江咸潮入侵问题,基于三维数值模拟成果,分析了东江南支流咸潮上溯特征及盐度输运机理。结果表明:东江咸潮上溯与潮位相位变化基本一致,在一个大、中、小潮周期内,盐度最大值出现在大潮期间;东江南支流总体处于盐度充分混合至部分混合状态,盐度垂向分布均匀;东江咸潮上溯主要是径流和潮流动力强弱对抗的结果,基本不存在垂向环流的输运,增大下泄径流量是减轻东江咸潮入侵的最有效措施。

To solve the problem of saltwater intrusion,the saltwater intrusion characteristics and salinity transport mechanism in the south branch of the Dongjiang River were analyzed based on three-dimensional numerical simulation.The results show that the change of saltwater intrusion in the Dongjiang River has the same periodicity as that of tidal level,and the maximum salinity occurs during the spring tide in a period of spring,moderate,and neap tides.The south branch of the Dongjiang River is generally in a state of full mixing to partial mixing of salinity,and the salinity distribution is uniform in the vertical direction.The occurrence of saltwater intrusion in the Dongjiang River depends on the contrast between the effects of runoff and tidal current,and there is almost no vertical circulation transport.Therefore,increasing the runoff discharge is the most effective measure to reduce the saltwater intrusion in the Dongjiang River.