Salt marshes are ecologically and physically essential habitats in coastal intertidal flats. In addition to providing nursery grounds for various wildlife, vegetation in marshes acts as a buffer zone that slows flooding waters. Extensive marsh platforms can also attenuate wave energy to protect coastal communities. Complex geometries make it challenging for models to capture the spatiotemporal variabilities in the transport of lateral water and sediment over tidal creek-marsh complexes. To study water exchange processes between tidal creeks and marshes, field observations were conducted within tidal creeks in the Chongming Dongtan Shoal of the Changjiang Estuary, an area dominated by Phragmites australis, Scirpus mariqueter, and Spartina alterniflora. A coupled wave-current-sediment-vegetation model that parameterized the three vegetation species was developed and applied to the tidal creek complex of Chongming Dongtan. Validated with the observational data, the modeling results were used to examine the influence of vegetation on flooding/draining processes within tidal creeks and mudflats. The model showed that vegetation not only modified the flow pattern at high tide in the high-elevation marsh but also significantly intensified the tidal flows in tidal creeks in the low-elevation regions. Both the observations and model detected significant transport of water and sediment from the marsh to tidal creeks, seaward sediment export over tidal cycles. The simulated salinity exhibited a considerable spatial gradient, matching well with the salt tolerances of the major vegetation types. This model can be potentially used to determine how future scenarios of hydrodynamics could affect vegetation zonation.

中文翻译：

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植被对盐沼-潮汐溪系统横向交换的影响

盐沼是沿海潮间带生态和物理上必不可少的栖息地。除了为各种野生动物提供苗圃外，沼泽中的植被还可以作为缓冲带，减缓洪水泛滥。广泛的沼泽平台还可以减弱波浪能以保护沿海社区。复杂的几何形状使模型难以捕捉潮汐小溪 - 沼泽复合体上横向水和沉积物运输的时空变化。为了研究潮汐小溪与沼泽之间的水交换过程，在长江口崇明东滩滩的潮汐小溪内进行了实地观察，该地区以芦苇、马鞭草和互花米草为主。. 开发了一种对三种植被物种进行参数化的波-流-沉积物-植被耦合模型，并将其应用于崇明东滩潮汐河群。通过观测数据验证，建模结果用于检查植被对潮汐小溪和泥滩内洪水/排水过程的影响。该模型表明，植被不仅改变了高海拔沼泽高潮时的水流格局，而且显着增强了低海拔地区潮汐小溪的潮汐流动。观测和模型都检测到水和沉积物从沼泽到潮汐小溪的显着迁移，潮汐循环中向海的沉积物输出。模拟的盐度表现出相当大的空间梯度，与主要植被类型的耐盐性很好地匹配。