Modeling Hydrodynamic and Hydrological Processes in Tidal Wetlands

Hydrologic processes in tidal wetlands are important regulators controlling the growth and productivity of salt marsh plants. Understanding hydrodynamic and hydrological processes is therefore critical to sustaining ecosystem functions and productivity in tidal wetlands. We used remote sensing and geographic information system to determine the spatial distributions of Suaeda heteroptera and Phragmites australis plants on the tidal-flats of Liao River Estuary (LRE), China. Next, hydrodynamic modelling was performed to characterize the water levels and tidal currents in these wetland waters. After extensive calibration and validation against field data, we proposed a 2D circulation structure for the LRE that can be used to calculate the hydrological parameters in different areas of the tidal wetlands. The simulation results showed that the hydrological characteristics of the tidal wetlands were primarily dependent on local topography and water level. The prevalent plant community in the LRE, dominated by Suaeda heteroptera, was abundant across a large range of flood times (0.79 ~ 3.22 h/day), inundation frequencies (11 ~ 52 times/month), and max flooding depths (0.42 ~ 0.81 m). However, certain hydrological conditions did appear to limit the spatial distributions of wetland plant communities. These findings have provided detailed methods of a novel approach to quantitatively assess habitat status in tidal-flat wetlands.