剧烈变化的径流对九龙江河口流动特性的影响

Change of Flow Characteristics at Jiulongjiang Estuary under Different Runoff

为了认识不同径流与潮流博弈引发的河口流动特性的变化规律,采用数学模型和大型河口物理模型耦合的方法,系统研究了九龙江下游北溪浦南水文站、西溪郑店水文站以下广大河口区域的流场及水位场的变化。结果表明,天然状态下,当九龙江径流为15 540、2 896、374m3/s且河口恰遇典型日天文大潮时,潮流界分别位于甘文尾后的红树林海洋自然保护区、南北中港以及西溪河道的渡头村和北溪河道的科坑村,径流变化可使潮流界上溯约35km;不同径流条件下河口三角洲的南港、中港、北港行洪和纳潮的分流比及流动特性发生显著变化;九龙江葫芦状河口及厦门岛周边存在径流对潮位影响的分界区,厦门岛北支口门区域受九龙江北溪和西溪径流影响很小。

In order to research the variation rule of river flow characteristics caused by different runoff and tide opposability,mathematical model and the large estuary physical model coupling method was used to study the change of water level and flow field of the downstream of Jiulongjiang Beixi Punan and the downstream of Xixi Zhengdian hydrological station.The results show that when the runoff of Jiulongjiang is 15 540 m3/s,2 896 m3/s,374 m3/s respectively,tidal current limit is located in Jiulongjiang estuary Mangrove Marine nature reservest,Nangang-Beigang-Zhonggang and Xixi dutou-Bixi kekeng.Runoff change can make tidal current limit back about 35 km.Under the conditions of different runoff,the diversion ratio and flow characteristics changed significantly in Nangang,Beigang and Zhonggang.The influence of runoff boundary area exists in Jiulongjiang gourd shape estuary.The Jiulongjiang Beixi and Xixi runoff has little impacts on Xiamen northern estuary.