Author(s): Wang Pu; Gu Zhitong; Ye Shengbo; Liu Feng

Linked Author(s):

Keywords: Microtidal estuary; Saltwater intrusion; The mouth bar; Numerical simulation; Mechanism analysis

Abstract: The estuary's topography, especially the mouth bar, is crucial for preventing saltwater intrusion. This study focuses on the mouth bar's impact on saltwater intrusion in the Modaomen Estuary. It employs the Delft3D numerical model to construct two estuary models -- with and without the mouth bar -- to explore its impact on saline intrusion during the dry season and reveal the mechanisms. The model results show that, under the effect of river flow and tide, the mouth bar has a significant effect on reducing the saltwater intrusion distance by 54.5% on spring tide and 25% on neap tide. The intensity of the mouth bar's weakening effect on the saltwater intrusion is different at different tides, which is mainly caused by the inconsistent changes of stable shear flux and tidal oscillation flux during spring and neap tides. During neaps, mouth bar will increase stable shear while weakening the tidal action intensity, resulting in a smaller weakening effect on salt water intrusion than that at spring tides. This study deepens the understanding of saltwater intrusion mechanisms in complex estuarine topography, with practical significance for water security and salt tide prevention in the estuarine area.

DOI: https://doi.org/10.3850/iahr-hic2483430201-181

Year: 2024