Morphodynamic Responses to the Hong Kong-Zhuhai-Macao Bridge in the Pearl River Estuary, China

Human activities such as constructing large bridges, performing land reclamation, and creating harbors in complex tidal estuaries can result in severe and undesirable morphodynamic responses. This study investigates morphodynamic responses to the construction of the Hong Kong-Zhuhai-Macao Bridge (HZMB) in Lingdingyang Bay of the Pearl River estuary (LBPRE). The LBPRE in China is an important estuary with unique geomorphic features, complex hydrodynamic sediment conditions, dense shipping routes, high ship density, and a high navigation grade. The HZMB, a major sea-crossing transportation project consisting of bridges, a tunnel, and man-made islands, is being designed to cross the LBPRE. The morphodynamic responses resulting from the HZMB are likely to be significant. Therefore, it is necessary to carry out studies to optimize the HZMB design to minimize its impacts on hydrodynamics, sediment environment, harbors, and navigational channels as much as possible. In this article, the natural hydrodynamic and sediment conditions are first analyzed on the basis of in situ data. Next, a numerical model of tidal current, sediment movement, and seabed deformation based on TK-2D software is set up with an irregular triangular grid. The model is calibrated with in situ data, and the results show that the calculated tidal levels, tidal currents, suspended load concentrations, and seabed deformations are all in good agreement with field data. The model is then applied to carry out high-resolution simulations for design optimization of the HZMB from the perspective of its impacts on morphodynamics and hydrodynamics, as well as on harbors and channels. The study shows that the proposed HZMB design is feasible in terms of the morphodynamic responses. The conclusions provide an important foundation for the construction of the HZMB project.