Influence of Topographic and Shoreline Changes on Tidal Current Asymmetry in Lingding Bay

LIU Ming-lin, JI Xiao-mei, HUANG Li-ming, ZHANG Wei

Journal of Changjiang River Scientific Research Institute ›› 2026, Vol. 43 ›› Issue (1) : 86-94.

PDF(18196 KB)
PDF(18196 KB)
Journal of Changjiang River Scientific Research Institute ›› 2026, Vol. 43 ›› Issue (1) : 86-94. DOI: 10.11988/ckyyb.20241034
Hydraulics

Influence of Topographic and Shoreline Changes on Tidal Current Asymmetry in Lingding Bay

Author information +
History +

Abstract

[Objective] Topographic and shoreline changes caused by human activities such as tidal flat reclamation, channel deepening by dredging, and seabed sand mining further interfere with tidal wave propagation in estuarine and coastal areas. These changes have significant impacts on key environmental and engineering issues, including channel maintenance and management, the safety and stability of coastal hydraulic structures, the transport patterns of sediment and pollutants, and saltwater intrusion. Previous studies on tidal asymmetry in the Pearl River Estuary have mostly focused on tidal asymmetry itself; however, tidal current asymmetry induced by topographic and shoreline changes exerts a greater influence on material transport. To systematically evaluate the disturbance mechanisms of such human activities on the tidal dynamic system, this study investigates the tidal current asymmetry in the Lingding Bay area caused by topographic and shoreline changes using the skewness method. [Methods] A high-resolution hydrodynamic numerical model covering the river network, estuary, and adjacent sea areas of the Pearl River Delta was established based on Delft3D-Flow Flexible Mesh. The model was rigorously calibrated and validated using observed water levels and current velocity data from multiple stations. The simulated results agreed well with the observations, indicating that the model had reliable predictive capability. On this basis, sensitivity experiments with different shoreline and topographic configurations were conducted. Using the T-Tide harmonic analysis tool, the variations in amplitude and phase of the main astronomical tidal constituents O1, K1, M2, and S2 and the shallow-water constituents M4 and MS4 between the 1970s and the 2010s were analyzed and summarized. The skewness method was adopted to calculate the flow velocity asymmetry (FVA) and flow duration asymmetry (FDA), to reveal the spatial distribution patterns of FVA and FDA in different decades, and to explore the contributions of major tidal constituent combinations to FVA and FDA. [Results and Conclusion] (1) The tidal dynamics in the Lingding Bay area exhibited a distinct tidal current asymmetry. Shoreline extension caused by reclamation and topographic incision resulting from channel dredging led to a general increase in the amplitudes of major shallow-water constituents and a northward shift of tidal wave phases, while the phase difference between the bay mouth and bay head decreased. These changes collectively weakened the ebb dominance and shortened the ebb duration, thereby enhancing the overall tidal current asymmetry in this region. (2) For different types of tidal current asymmetry, FVA was mainly controlled by topographic changes, with the combinations of K1/O1/M2 tidal constituents and the residual current term playing a dominant role. The FVA generally exhibited ebb dominance, favoring seaward sediment transport. The skewness values of FVA within Lingding Bay still showed a spatially decreasing trend along the bay. (3) In contrast, FDA was more sensitive to shoreline changes. Its variation was mainly controlled by the combinations of tidal constituents such as M2/M4 and M2/S2/MS4. Topographic and shoreline changes induced by human activities further enhanced the contribution of these tidal constituent combinations to FDA. Overall, the FDA exhibited a shorter ebb duration, with its asymmetry increasing from the bay mouth toward the bay head.

Key words

tidal current asymmetry / Lingding Bay / topographic and shoreline changes / combinations of tidal constituents

Cite this article

Download Citations
LIU Ming-lin , JI Xiao-mei , HUANG Li-ming , et al. Influence of Topographic and Shoreline Changes on Tidal Current Asymmetry in Lingding Bay[J]. Journal of Changjiang River Scientific Research Institute. 2026, 43(1): 86-94 https://doi.org/10.11988/ckyyb.20241034

References

[1]
陈道信, 陈木永, 张弛. 围垦工程对温州近海及河口水动力的影响[J]. 河海大学学报(自然科学版), 2009, 37(4):457-462.
(CHEN Dao-xin, CHEN Mu-yong, ZHANG Chi. Influence of Reclamation Projects on Hydrodynamic Force in Offshore and Estuary of Wenzhou[J]. Journal of Hohai University (Natural Sciences), 2009, 37(4): 457-462.) (in Chinese)
[2]
方强, 黄赛花, 许雪峰, 等. 围垦工程群对杭州湾南岸累积水动力影响分析[J]. 科学技术与工程, 2020, 20(13): 5338-5344.
(FANG Qiang, HUANG Sai-hua, XU Xue-feng, et al. Analysis of the Influence of Reclamation Engineering Group on the Accumulated Hydrodynamics in the South Coast of Hangzhou Bay[J]. Science Technology and Engineering, 2020, 20(13):5338-5344.) (in Chinese)
[3]
冯曦, 丁志伟, 冯辉, 等. 南黄海辐射沙洲潮流不对称性对岸线变动的响应[J]. 海洋学报, 2022, 44(6):1-9.
(FENG Xi, DING Zhi-wei, FENG Hui, et al. Responses of Tidal-current-asymmetry to Shoreline Variation in Radial Sand Ridges in the South Yellow Sea[J]. Haiyang Xuebao, 2022, 44(6): 1-9.) (in Chinese)
[4]
CHANT R J, SOMMERFIELD C K, TALKE S A. Impact of Channel Deepening on Tidal and Gravitational Circulation in a Highly Engineered Estuarine Basin[J]. Estuaries and Coasts, 2018, 41(6): 1587-1600.
[5]
陈小文, 刘霞, 张蔚. 珠江河口滩涂围垦动态及其影响[J]. 河海大学学报(自然科学版), 2011, 39(1): 39-43.
(CHEN Xiao-wen, LIU Xia, ZHANG Wei. Shore Reclamation in Pearl River Esturay and Its Impact Analysis[J]. Journal of Hohai University (Natural Sciences), 2011, 39(1): 39-43.) (in Chinese)
[6]
LUO X L, ZENG E Y, JI R Y, et al. Effects of In-channel Sand Excavation on the Hydrology of the Pearl River Delta, China[J]. Journal of Hydrology, 2007, 343(3/4):230-239.
[7]
郑金海, 鲍仕昱, 张蔚, 等. 河床下切对珠江三角洲峰值水位演变的影响[J]. 河海大学学报(自然科学版), 2022, 50(4): 1-6.
(ZHENG Jin-hai, BAO Shi-yu, ZHANG Wei, et al. Effect of Channel Deepening on the Evolution of Peak Water Level in the Pearl River Delta[J]. Journal of Hohai University (Natural Sciences), 2022, 50(4): 1-6.) (in Chinese)
[8]
宫清华, 周晴, 李平日, 等. 珠江口伶仃洋地貌特征演变与纳潮能力变化研究[J]. 海洋学报, 2019, 41(1):98-107.
(GONG Qing-hua, ZHOU Qing, LI Ping-ri, et al. Morphological Change and Tidal Prism Variation in the Lingdingyang, Zhujiang River Estuary[J]. Haiyang Xuebao, 2019, 41(1): 98-107.) (in Chinese)
[9]
王宗旭, 乔煜, 季小梅, 等. 珠江河口岸线变化对潮动力的影响[J]. 科学技术与工程, 2020, 20(3):1171-1180.
(WANG Zong-xu, QIAO Yu, JI Xiao-mei, et al. The Influence of Coastline Changes on Tidal Dynamics in the Pearl River Estuary[J]. Science Technology and Engineering, 2020, 20(3): 1171-1180.) (in Chinese)
[10]
童朝锋, 司家林, 张蔚, 等. 伶仃洋洪季潮波传播变形及不对称性规律分析[J]. 热带海洋学报, 2020, 39(1):36-52.
Abstract
珠江河口伶仃洋水域潮波传播变形及其不对称性关系对河口动力环境和物质输运产生影响。研究根据珠江口伶仃洋及东四口门19个潮位站2011年6月实测逐时潮位, 利用收缩河型沿程潮幅解析理论, 阐释伶仃洋从桂山岛上行沿程潮汐传播规律特征; 在调和分析基础上, 应用偏度理论和分潮组合分析方法, 阐明了伶仃洋东西岸及洪奇门、蕉门内潮汐不对称性分布特征, 对照数值研究结果, 指出伶仃洋至虎门之间水域导致潮汐不对称性的主控因素及响应规律。研究表明, 河口平面形态呈近似指数收缩特征的伶仃洋, 沿程潮幅的变化符合指数收缩型河口波幅解析变化规律, 东岸潮幅高于西岸的主要原因是东岸水深大于西岸, 其次是科氏力影响; 行进潮波虽受地形摩擦耗能及非线性作用下不同频率分潮间能量迁移的影响, 但收缩河口能量汇聚效应可以保证收缩段天文分潮潮幅减缓衰减甚至增加, 半日分潮能量汇聚效果强于全日分潮, 各非线性项作用促使浅水分潮产生并持续增能, 保证一定距离内沿程潮幅的增大; 潮汐不对称性的偏度由湾口落潮占优向湾顶涨潮占优发展, 在伶仃洋中部赤湾至金星港一线转为涨潮占优, 产生该现象的原因是自湾口向湾顶不同频率间天文分潮K<sub>1</sub>-O<sub>1</sub>-M<sub>2</sub>的相互作用, 导致表现为落潮优势潮的不对称性减弱, 而天文分潮M<sub>2</sub>和其对应的浅水分潮倍潮M<sub>4</sub>组合作用使涨潮优势偏度值的不对称性增强; 收缩河口形态属性要素中, 水深是影响潮不对称性的最主要因素。
(TONG Chao-feng, SI Jia-lin, ZHANG Wei, et al. Analysis of Tidal Wave Propagation Distortion and Asymmetry in Lingding Bay during Wet Season[J]. Journal of Tropical Oceanography, 2020, 39(1):36-52.) (in Chinese)

Tidal wave propagation and tidal asymmetry in the Pearl River Estuary and Lingding Bay water areas affect estuarine dynamic environment and material transport in the areas. Based on tidal level statistics during June 2011 to July 2011 measured by stations set up in four east estuaries in the Pearl River and Lingding Bay, the theory of convergent estuarine tidal amplitude along the way is used for obtaining an analytic solution, and characteristics of tidal wave propagating from Guishan Island toward upstream is illustrated. Based on harmonic analysis, theory of skewness and method of constituent combination, tidal asymmetry distribution characteristics of east and west coasts in Lingding Bay, Hongqi outlet and Jiao outlet are explained; contrasts with analytical results, main control factors and response regulation of water area between Lingding Bay to Hu Estuary are noted. Our research shows that in Lingding Bay, which is approximately consistent with exponential convergent estuary, the tidal amplitude nearly accords with the change rule of the tidal amplitude analytical solution in exponential convergent estuary. The reason why tidal amplitude in the east coast being higher than in the west coast is that the water depth of the east coast is larger than that of the west coast; secondly, tidal amplitude is impacted by the Coriolis force. Although propagating wave is influenced by roughness consumes energy, and by energy transfer among constituents with different frequencies caused by nonliner effect, the convergence effect of convergent estuary can make sure that amplitudes of astronomical constituents keep steady even rise up in convergent segment, and the impact extent of convergence effect in semi-diurnal constituent is larger than that in diurnal constituent. Each nonliner term’s effect promotes the generation of shallow water constituent and increases energy continuously, making amplitude of shallow water constituent rising within a distance. Skewness of tidal asymmetry changes from ebb dominance in bay mouth to flood dominance in bay bottom, and transform to flood dominance at the line of Chiwan to Jinxing Port, which is located in the middle of Lingding Bay. It suggests that the decrease of ebb dominance asymmetry, which is caused by interaction of astronomical constituents K1-O1-M2 with different frequency, and the increase of flood dominance asymmetry, which is caused by interaction of astronomical constituent M2 with its shallow water overtide M4, leads to the phenomenon. Water depth is the most important factor, which influences tidal asymmetry in properties of a convergent estuary.

[11]
YANG Q, HU S, FU L, et al. Responses of Tidal Duration Asymmetry to Morphological Changes in Lingding Bay of the Pearl River Estuary[J]. Frontiers in Marine Science, 2022, 9: 983182.
Tidal asymmetry is one of the main factors for generating net transport for waterborne materials in tidal estuaries, and thus, this phenomenon has significant influences on controlling morphological development and the ecological environment. Tidal propagation is sensitive to changes in the coastline and geometry of estuarine regions. Moreover, tidal waveforms vary with various factors, such as coastline changes and bathymetry evolution due to local anthropogenic activities. The topography of Lingding Bay (LDB) of the Pearl River Estuary (PRE) has greatly changed since the 1960s because of human interventions, but the response of tidal duration asymmetry (TDA) to morphological changes is still poorly understood. Utilizing the two-dimensional Delft-3D flexible mesh numerical model, the spatial pattern of TDA and its primary contributors in LDB of the PRE were reproduced for 1964, 1989, and 2016, accounting for the changes in both shoreline and bathymetry owing to human interventions. The results reveal that as the tidal wave propagates upstream, the tidal skewness increases from negative values to positive values longitudinally, indicating the transition from a shorter ebb-duration state to a shorter flood-duration state. Additionally, a prominent shift in TDA and its primary contributors takes place approximately in the period of 1989. In 1964-1989, the tidal skewness increased by at least 0.1 throughout the LDB, indicating that the flood duration of the entire bay was shortened significantly. However, in 1989-2016, the tidal skewness decreased by at most 0.15 throughout the LDB, representing a longer flood duration in the entire LDB. The scenario simulations reveal that reclamation-induced shoreline changes control the increase in TDA and its primary contributors by enhancing width convergence of estuary in the period of 1964-1989. Conversely, the increase in water depth plays a vital role in the decrease of TDA in the period of 1989-2016. The results obtained from this study are particularly useful for understanding the controlled factors contributing to net sediment transport and the associated long-term morphological evolution in estuaries heavily impacted by human interventions.
[12]
崔伟中. 珠江河口滩涂湿地的问题及其保护研究[J]. 湿地科学, 2004, 2(1):26-30.
(CUI Wei-zhong. Study on Protection of Mudflat Wetland in the Pearl River Estuary[J]. Wetland Science, 2004, 2(1): 26-30.) (in Chinese)
[13]
赵焕庭. 珠江三角洲的形成和发展[J]. 海洋学报, 1982, 4(5): 595-607.
(ZHAO Huan-ting. The Formation and Development of the Pearl River Delta[J]. Acta Oceanologica Sinica, 1982, 4(5): 595-607.) (in Chinese)
[14]
侯庆志, 陆永军, 王志力, 等. 河口湾水动力环境对滩涂利用的累积响应:以珠江口伶仃洋为例[J]. 水科学进展, 2019, 30(6):789-799.
(HOU Qing-zhi, LU Yong-jun, WANG Zhi-li, et al. Cumulative Response of Estuarine Bay Hydrodynamic Environment to Human Activities: Example of Lingding Bay of the Pearl River Estuary[J]. Advances in Water Science, 2019, 30(6):789-799.) (in Chinese)
[15]
Deltares. D-flow FM User Manual[M]. Delft: Deltares, 2016.
[16]
EGBERT G D, EROFEEVA S Y. Efficient Inverse Modeling of Barotropic Ocean Tides[J]. Journal of Atmospheric and Oceanic Technology, 2002, 19(2): 183-204.
[17]
NIDZIEKON J. Tidal Asymmetry in Estuaries with Mixed Semidiurnal/Diurnal Tides[J]. Journal of Geophysical Research: Oceans, 2010, 115(C8):C08006.
[18]
ALLENJ I, SOMERFIELD P J, GILBERT F J. Quantifying Uncertainty in High-resolution Coupled Hydrodynamic-ecosystem Models[J]. Journal of Marine Systems, 2007, 64(1/2/3/4): 3-14.
[19]
HOITINKA J F, HOEKSTRA P, VAN MAREN D S. Flow Asymmetry Associated with Astronomical Tides: Implications for the Residual Transport of Sediment[J]. Journal of Geophysical Research: Oceans, 2003, 108(C10):3315.
[20]
ZHANG W, CAO Y, ZHU Y, et al. Unravelling the Causes of Tidal Asymmetry in Deltas[J]. Journal of Hydrology, 2018, 564: 588-604.
PDF(18196 KB)

Accesses

Citation

Detail

Sections
Recommended

/