Dynamic evolution of tidal networks under the combined effect of de-reclamation and decrease of sediment supply

IF 2.1 3区地球科学 Q2 OCEANOGRAPHY

Continental Shelf Research Pub Date : 2024-07-05 DOI:10.1016/j.csr.2024.105274

Shang Yu , Fan Xu , Zhong Peng , Leicheng Guo , Xianye Wang , Weiming Xie , Chunyan Zhu , Zhengbing Wang , Qing He

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引用次数: 0

Abstract

De-reclamation is a common strategy used for the restoration of tidal flats. In this study, we investigate the morphodynamic response of tidal channel networks and tidal flats after de-reclamation initiatives using the Delft3D numerical model. We find that tidal channel networks that have undergone reclamation and retreat projects have a lower drainage density (8.95 km⁻¹) than that of channel networks that formed naturally (11.33 km⁻¹), and the drainage efficiency of natural formed channel networks is almost three times greater than restored channel networks. These findings indicate that de-reclamation alone cannot fully erase the imprinting of the previous reclamation. We also find that the ultimate effectiveness of de-reclamation is affected by the geographical layout and unchanneled path length of the inchoate main creek system. In addition, following the implementation of de-reclamation, the immediate opening of previously enclosed areas amplifies the tidal prism, thereby intensifying tidal scouring and resulting in significant erosion, with erosion rate reaching hundreds of millimeters per day. Such losses can be remediated under sufficient sediment supply and prevented through the construction of artificial channels. However, this severe erosion may escalate under an insufficient sediment supply or a heightened tidal prism, potentially leading to permanent loss. These findings constitute an important reference for future engineering practices that support the safety and sustainability of coastal resources.

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在围垦和沉积物供应减少共同作用下潮汐网络的动态演变

填海是恢复滩涂的常用策略。在本研究中，我们利用 Delft3D 数值模型研究了退垦后潮汐河道网和滩涂的形态动力学响应。我们发现，经过填海和撤退工程的潮汐河道网的排水密度（8.95 km-1）低于自然形成的河道网（11.33 km-1），而自然形成的河道网的排水效率几乎是经过修复的河道网的三倍。这些研究结果表明，仅靠开垦并不能完全消除先前开垦留下的印记。我们还发现，开垦的最终效果受到地理布局和不完整主溪流系统的无渠道长度的影响。此外，在实施填海工程后，原先封闭的区域立即开放，扩大了潮汐棱镜，从而加剧了潮汐冲刷，造成严重侵蚀，侵蚀速度可达每天数百毫米。这种损失可以在有足够沉积物供应的情况下得到补救，也可以通过修建人工河道加以防止。然而，在沉积物供应不足或潮汐棱镜增加的情况下，这种严重的侵蚀可能会加剧，从而可能导致永久性损失。这些研究结果为今后的工程实践提供了重要参考，有助于沿海资源的安全和可持续发展。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Continental Shelf Research 地学-海洋学

CiteScore

4.30

自引率

4.30%

发文量

136

审稿时长

6.1 months

期刊介绍： Continental Shelf Research publishes articles dealing with the biological, chemical, geological and physical oceanography of the shallow marine environment, from coastal and estuarine waters out to the shelf break. The continental shelf is a critical environment within the land-ocean continuum, and many processes, functions and problems in the continental shelf are driven by terrestrial inputs transported through the rivers and estuaries to the coastal and continental shelf areas. Manuscripts that deal with these topics must make a clear link to the continental shelf. Examples of research areas include: Physical sedimentology and geomorphology Geochemistry of the coastal ocean (inorganic and organic) Marine environment and anthropogenic effects Interaction of physical dynamics with natural and manmade shoreline features Benthic, phytoplankton and zooplankton ecology Coastal water and sediment quality, and ecosystem health Benthic-pelagic coupling (physical and biogeochemical) Interactions between physical dynamics (waves, currents, mixing, etc.) and biogeochemical cycles Estuarine, coastal and shelf sea modelling and process studies.