Current reversals in a large tidal river

摘要: Abstract A tidal river is a special zone where the basic hydrodynamic process interaction between riverine flow and tides. Existing studies focus mainly on water level fluctuations, while effort limited regarding regime uni- bi-directional currents. Along river, current direction reverses landward meets with seaward flow. So far, occurrence movement of reversal not fully investigated, number location points are well understood. In this study, in Yangtze was simulated using model, phenomenon reversals were investigated. It found that dry season up to three may occur simultaneously, including two convergence one divergence point, separating entire into seaward-current reaches landward-current reaches. These multiple result from co-existence preceding present flood waves. During spring tide peak flux wave can reach 10,000 m3/s, about same magnitude as discharge length occupation large 120 km. also point always coexists zero-gradient level, downstream point. The shift mouth consecutively, could finally disappear farther at upper river. bidirectional extend 550 200 km upstream wet seasons, respectively. influenced by regulation Three Gorges Dam. movements furtherly have significant impact local material transportation.