Study on hydrodynamic simulation and improvement scheme of urban wetlands in tidal reaches

Wetlands play crucial roles in carbon sequestration, oxygen release, and water conservation. Enhancing water exchange capacity is a key focus in wetland research. However, there is a relative scarcity of studies on wetland water regulation measures under varying tidal water levels. To address this gap, a two-dimensional hydrodynamic model was developed, using the Lvshuiwan Wetland in the Nanjing section of the Yangtze River as a case study. The model was employed to simulate and propose improvement strategies for urban wetlands in tidal areas. The study involved calculating the wetland flow patterns under different hydrological conditions and sluice pump scheduling schemes. It also examined the impact of tidal level changes on the hydrodynamics of Lvshuiwan Wetland, and evaluated the effectiveness of different sluice pump scheduling measures on water flow. The findings indicate that combined sluice-pump operations can significantly enhance the hydrodynamic forces in most areas during the dry season. However, certain stagnant areas, such as pits outside the main trough, require improvement in the self-purification capacity of the water through wetland vegetation reconstruction. During the months of April and May, characterized by frequent algae outbreaks, the combined operation of sluice pumps can improve the hydrodynamic conditions in the upstream area of Lvshuiwan Wetland. In the downstream area, where the improvement effect is not as pronounced, it is advisable to introduce water refill points to mitigate the risk of water eutrophication. This study provides a scientific foundation for the design, construction, and management of Lvshuiwan Wetland.