Abstract: In recent years, the implementation of many projects in the north branch of the Yangtze River estuary, such as the regulation project of Xincun shoal and the reclamation project in the middle and lower reach of Haimen reach, have narrowed the river width, changed the boundary condition and river-tidal dynamics of the north branch. In the aim of understanding the characteristics of tidal bores in the north branch, we observed the tidal bores by collecting tide level using self-recording tide gauge, visually observing tide rip on bank, observing flow velocity by buoys, and observing tidal bores on speed boat. We found that tidal bore mainly happens in shallow shoal area including the upper reach of Qinglong harbor and Chonghai ferry dock, with the height of tidal bore reaching 0.63 m and 0.74 m, respectively. In addition, one-line bore still exists in the reach from Lingdian shoal to the upstream shoals of Chonghai ferry dock. By recording the approximate locations of tidal bore’s generation, development, damping and vanishing, and analyzing the origin, type and characteristics of tidal bore, we can provide basic data for researching the interactions between river bed erosion/deposition and special hydrodynamic conditions in the middle and upper reaches of the north branch, and also would offer technical support for further stabilizing the river regime and utilizing the navigation channel in the north branch reasonably.

Key words: tidal bore, tidal level, tide rip, tidal wave, tide gauge, Yangtze River estuary, north branch