To investigate the influences of 12.5m deep-water channel project and sea level rise (SLR) on the hydrodynamic factors in Fujiangsha waterway of the Yangtze River, a two-dimensional Delft3D-FLOW hydrodynamic model was established. This model performed well to reproduce the tide level and flow velocity. Simulations were then conducted by putting the dams into the verified numerical model and adding 1m water depth to the open sea. Results demonstrated that both regulation project and SLR have significant influences on the hydrodynamic factors in Fujiangsha waterway. This study will be beneficial to the management and planning of the waterway.
The construction project of 12.5m deep water channel of the Yangtze River below Nanjing city is one of the major projects with the largest investment scale and the most complicated technology in China's inland water transportation during the 12th Five Year Plan period. The first-stage construction project covers Taicang to Nantong, which was completed in December 2015. And the second phase from Nantong to Nanjing has been fulfilled in May 2019. The Fujiangsha waterway section presents the pattern of "two levels of split and compresence of three navigable branches" on the plane (Qu and Ma, 2019). Because of its complex terrain conditions and the severe evolution of the shoals and troughs, it is one of the key waterway sections in the project. Relying on the implementation of the engineering arrangement, the hydrodynamic of the Fujiangsha waterway section has changed a lot. Therefore, it is instrumental in the planning and development of Fujiangsha waterway through analyzing the hydrodynamic in the field and evaluating the effect of the regulation project.
As Fujiangsha waterway is a typical tidal reach, its regulation and management need to consider the influence of sea level rise (SLR). SLR is a critical and uncertain climate change risk. It is a serious consequence of ongoing climate change, and its confident projection into the remainder of this century (and beyond) is important for mitigating and managing risk in the coastal zone. It will not only increase the probability of occurrence of storm surge, huge wave, saltwater tide and soil salinization, but also increase the average sea level and characteristic tide level together with enhancing the wave action near the shore as well as intensify the impact of disasters. Therefore, it is of great significance for its risk management and future planning to analyze the hydrodynamic changes in Fujiangsha waterway section caused by SLR.