Tidal Dynamics Research Articles

Impact of trends in river discharge and ocean tides on water level dynamics in the Pearl River Delta

The spectrum of tidal and subtidal water level variations in river deltas responds to river discharge variation, ocean tides, and human activities of many kinds. It remains a contemporary challenge to identify the main sources of changes in tidal dynamics in deltas, because of nonlinear interactions between tides and the river discharge in a changing setting. Understanding the main forcing factors controlling the evolution of mean water levels and the associated amplitudes and phases of tidal constituents can help to understand the causes of floods and the occurrence of low flows hindering navigation. Here, a nonstationary harmonic analysis tool (NS_TIDE) is applied to hydrological data from 14 stations in the Pearl River Delta (PRD) spanning the period 1961–2012. The water levels and main tidal constituent properties are decomposed into contributions of external forcing by river discharges and ocean tides, providing insight into the nonstationary tidal-fluvial processes. Significant temporal trends in mean water levels and tidal properties are observed in the PRD. Results indicate that there is spatial variability in the response of mean water levels and tidal properties to river discharge variation in the delta. The abrupt changes in bathymetry in the delta due to intensive sand excavation are likely responsible for the observed spatial variations in tidal response, which reduce the flood-dominant tidal asymmetry in this area.

Coastal ocean dynamics reduce the export of microplastics to the open ocean

Huge amounts of plastic waste are dumped into the ocean every year, forming large Garbage Patches. Countless microplastics, originating from fragmentation, weathering of larger objects or primary sources, pose a widespread ecological risk. In this study, the dispersion of suspended and floating microplastic particles in the East China Seas (ECSs) and adjacent seas was investigated via a coupled numerical model that included a Lagrangian particle tracking module. The role of tidal dynamics was considered in transporting the microplastic particles in the ECSs and adjacent seas. The results highlighted significant differences between the transport of suspended and floating microplastic particles. Although microplastic particles originating from different source areas followed different pathways, the Taiwan Strait, the Tokara Strait and the Tsushima Strait were identified as the major delivery channels. Of these, the Taiwan Strait played the most important role in the export of near-surface floating microplastic particles from the ECSs. The results showed that only a small fraction of the microplastic particles produced from the coastal waters of China (~18%) and Korea (~14%) entered the Pacific Ocean. However, nearly all of the microplastic particles originating from the west and south coasts of Kyushu Island entered the Pacific Ocean.

Microbial diversity and related secondary metabolite gene assortment at an estuarine mangrove ecosystem

Mangrove ecosystems are a major biodiversity hotspot of the world. The world heritage site Sundarbans is an archipelago with an estuarine mangrove ecosystem. It is assumed that each individual Island of the Sundarbans possess a unique biodiversity due to the seasonal variation of physicochemical parameters, along with tidal dynamics of Bay of Bengal. This study unfolds a time series analysis of microbial diversity using high-resolution 16S rRNA tag pyrosequencing. Eight soil samples were collected over three years at a pristine temperate estuarine site located at the sea mangrove interface at the island of Kalash. Apart from the predominant phyla such as Proteobacteria [31.6%], Chloroflexi [10.7%], Firmicutes [7%] Bacteroidetes [7%] and Actinobacteria [1.2%], soil from Kalash also contained a significant amount of rare phyla NC10 and WS3 categorized as microbial dark matter (MDM). Variation in bacterial community composition occurs mainly as a result of the seasonal changes and consequent alterations of physicochemical parameters leading to microbial adaptations. Further we performed functional metagenomics to estimate the possibility of the synthesis of new natural compounds by diverse Polyketide Synthase (PKS). The data indicated diverse microbial origins of keto synthase sequences from polyketide synthase genes. Presence of this unique keto synthases confirmed the existence of a potential microbiome which may be capable of producing novel small molecules. This is the pioneering report to correlate the microbial community structure of Sundarbans with their potential to produce essential bioactive compounds.

The significance of coastal bathymetry representation for modelling the tidal response to mean sea level rise in the German Bight

Abstract. Due to climate change an accelerated mean sea level rise is expected. One key question for the development of adaptation measures is how mean sea level rise affects tidal dynamics in shelf seas such as the North Sea. Owing to its low-lying coastal areas, the German Bight (located in the southeast of the North Sea) will be especially affected. Numerical hydrodynamic models help to understand how mean sea level rise changes tidal dynamics. Models cannot adequately represent all processes in overall detail. One limiting factor is the resolution of the model grid. In this study we investigate which role the representation of the coastal bathymetry plays when analysing the response of tidal dynamics to mean sea level rise. Using a shelf model including the whole North Sea and a high-resolution hydrodynamic model of the German Bight we investigate the changes in M2 amplitude due to a mean sea level rise of 0.8 and 10 m. The shelf model and the German Bight Model react in different ways. In the simulations with a mean sea level rise of 0.8 m the M2 amplitude in the shelf model generally increases in the region of the German Bight. In contrast, the M2 amplitude in the German Bight Model increases only in some coastal areas and decreases in the northern part of the German Bight. In the simulations with a mean sea level rise of 10 m the M2 amplitude increases in both models with largely similar spatial patterns. In two case studies we adjust the German Bight Model in order to more closely resemble the shelf model. We find that a different resolution of the bathymetry results in different energy dissipation changes in response to mean sea level rise. Our results show that the resolution of the bathymetry especially in flat intertidal areas plays a crucial role for modelling the impact of mean sea level rise.

Dynamic programming and feedback analysis of the two dimensional tidal dynamics system

In this work, we consider the controlled two dimensional tidal dynamics equations in bounded domains. A distributed optimal control problem is formulated as the minimization of a suitable cost functional subject to the controlled 2D tidal dynamics equations. The existence of an optimal control is shown and the dynamic programming method for the optimal control of 2D tidal dynamics system is also described. We show that the feedback control can be obtained from the solution of an infinite dimensional Hamilton-Jacobi equation. The non-differentiability and lack of smoothness of the value function forced us to use the method of viscosity solutions to obtain a solution of the infinite dimensional Hamilton-Jacobi equation. The Bellman principle of optimality for the value function is also obtained. We show that a viscosity solution to the Hamilton-Jacobi equation can be used to derive the Pontryagin maximum principle, which give us the first order necessary conditions of optimality. Finally, we characterize the optimal control using the adjoint variable.

Hydrodynamics modeling with MIKE system in the Semak Daun Lagoon, Seribu Islands Indonesia

At low tide condition, the Semak Daun Lagoon (SDL) barrier reef is drowned during high tide and appeared to the surface during low tide. How are hydrodynamics in low tide and tidal conditions? This study aims to examine the pattern and current velocity in the SDL under four tidal conditions. The two-dimension model is built based on two motion generations namely wind pressure and tides. The discretization of the equation uses the finite volume method. Domain discretization is divided into 14,575 triangular elements with a grid area of 1,000 m2. The results of the model, verified with observational data in the field, show the similarity of tidal patterns and current velocity as indicated by the MAPE value of 7.9%, meaning that the model is well constructed. Current patterns generally move from southwest to northeast at high tide to low tide condition and vice versa at low tide to high tide condition. At low tide, there is a buildup of water mass in the lagoon because the only channel north is functioning as an outlet. This causes a slowing of current flow inside the lagoon and acceleration in the northern canal. Current velocity ranges from 0.02-0.51 m.s−1. The pattern and speed of the current in the lagoon are dominantly influenced by tidal dynamics. Residual current velocity varies in the range of 0.01-0.04 m.s−1.

Intertidal sedimentary dynamics in Mont-Saint-Michel bay, a study of its natural evolution and man-made modifications

Due to its exceptional tidal range and the immensity of its intertidal zones, Mont-Saint-Michel is a favored model for research on coastal hydro-sedimentary processes, present-day sedimentary dynamics and the reconstruction of coastal paleo-environments. The purpose of this article is to analyze the erosion/sedimentation processes which govern the sedimentary dynamics and the recent evolution of the characteristic sedimentary environments of the bay. The western bay head is made up of tidal sand and silt deposits, where the extent of the surface sediment reworking is less than 10 cm and linked to the nature of the substrate and the wind direction. Added to these tidal dynamics are the dynamics of the swell, which set coarse bioclastic sands in motion as the waves wash away the shore. These sands migrate on the tidal flat at rates of several dozen m/year and accumulate on the upper tidal flat, forming a relatively stable non-continuous coastal barrier of large shell banks. The eastern part of the bay is an estuarine zone, where the morpho-dynamics of the sandy tidal flat are constrained by shifting channels. Studies of the interaction between vegetation and sedimentation around Mont-Saint-Michel show sedimentary accretion rates varying from 0.2 to 10 cm/year, depending on the morpho-dynamic context of the salt marsh front. The volume of sediment deposited by the tide leads to cyclical deposition of calcareous muds followed by the steady advance of salt marshes at a rate of about 17 ha/year between La Chapelle Sainte-Anne and the Roche Torin point. The bay has filled for thousands of years to the rhythm of sea level oscillations, leading to the gradual infilling of the Dol marsh and the advance of the shoreline. In addition to this natural evolution, human activities have developed in the bay, both on the western tidal flat (fixed fisheries and shellfish farming) and on the eastern estuarine side (polder formation, construction of dikes and a dam) and have altered the landscapes, the historical evolution of which was reconstructed from old documents.

Supporting Coastal Resiliency by Investigating Tidal Reach and Inter-Connected Factors in Coastal Georgia

Increasing our understanding of the tidal dynamics, the extent of tidal reach, and storm surge impacts on near-coastal areas of Georgia and South Carolina rivers is a significant research opportunity. It has the potential to yield benefits to sustainable planning, ecosystem protection, and risk management for regulators and state agencies, local municipalities, coastal residents, and other regional stakeholders. This study leveraged existing United States Geological Survey (USGS) water level data for the Savannah River, added additional water level gauges in key areas for less than one year, and analyzed these combined large data sets with modified wavelet analysis and Fourier analysis. One significant outcome of the research included confirmation of river mile 45, historically referred to as Ebenezer Landing, as the head of tide. We also provide information on the dynamics of wave propagation through the near-coastal area of the Savannah River, give indication of critical areas of concern for flooding resulting from interactions between the interconnected factors affecting elevated upstream flows and storm tides, and discuss relevance of study results for various stakeholders.

Role of Stomata in Adaptation of Plantago maritima L. Plants to Tidal Dynamics on the White Sea Coast

Structural and functional traits in leaves of sea plantain (Plantago maritima L.) inhabiting intertidal and supratidal zones of the White Sea coast were studied. At the intertidal, the plants were found to have smaller and thicker leaves with more frequent stomata and thinner cover tissues in comparison with the plants collected from the supratidal. Leaf fluorescence and stomatal conductance obeyed the circadian rhythm in plants residing in the supratidal. The tested parameters considerably changed according to tidal dynamics in the intertidal plants. Two stable states (high and low tides) and two transition states (while water level ascends or descends) were defined. In both stable states, the plants demonstrated high functional parameters of fluorescence (Fv/Fm, Y(II), and ETR) and open stomata. In the transitional states, the stomata were partly closed, and the functional activity was inhibited. Leaf structural peculiarities, leaf gas films, the inducible CO2-concentrating mechanism, and the determining role of the stomata are considered in terms of the hypotheses explaining the responses of sea plantain to tidal dynamics on the White Sea coast.

Tidal dynamics along the western coast of the Saudi Arabia, the Red Sea

The tidal dynamics along the coastal region has more influence in the in the coastal physical and biological processes. The identifications of major tidal components can use to assess the influences of tides and can use to predict the tide along the coast. The present study focuses on comprehensive tidal analysis in the western coast of the Red Sea, Saudi Arabia. The harmonic analysis carried out to extract tidal constituents in spatially along the coast. Time series data collected from the coastal stations along the western coast of the Saudi Arabia used for tidal analysis. T_TIDE analyses were performed for extracting the tidal constituents. The study reveals the variations of tidal constituents in amplitudes and phases. The analysis well predicted water levels and it verified with field conditions.

Can Barrier Islands Survive Sea‐Level Rise? Quantifying the Relative Role of Tidal Inlets and Overwash Deposition

AbstractBarrier island response to sea‐level rise depends on their ability to transgress and move sediment onto and behind the barrier, either through flood‐tidal delta deposition or via overwash. Our understanding of these processes over decadal or longer timescales, however, is limited. Here we use a recently developed barrier island model (BRIE) to better understand the interplay between tidal dynamics, overwash fluxes, and sea‐level rise on barrier coasts and barrier island stratigraphy. Model results suggest that in microtidal environments with large alongshore sediment transport fluxes, tidal inlets are ephemeral and migrate rapidly. These conditions lead to effective deposition of flood‐tidal deltas and allow inlets to constitute most of the landward sediment flux. Whether barrier islands can survive sea‐level rise depends on the combined landward sediment flux from overwash and flood‐tidal delta deposition, likely making barrier islands with artificially stabilized inlets (via jetty construction or maintenance dredging) more vulnerable to sea‐level rise.

The Study of Tidal Current Dynamics and Impact of Bathymetry in Training the Currents along the Coast of Karachi, Pakistan

The Study of Tidal Current Dynamics and Impact of Bathymetry in Training the Currents along the Coast of Karachi, Pakistan

Non-linear aspects of the tidal dynamics in the Sylt-Rømø Bight, south-eastern North Sea

Abstract. This study is dedicated to the tidal dynamics in the Sylt-Rømø Bight with a focus on the non-linear processes. The FESOM-C model was used as the numerical tool, which works with triangular, rectangular or mixed grids and is equipped with a wetting/drying option. As the model's success at resolving currents largely depends on the quality of the bathymetric data, we have created a new bathymetric map for an area based on recent studies of Lister Deep, Lister Ley, Højer Deep and Rømø Deep. This new bathymetric product made it feasible to work with high-resolution grids (up to 2 m in the wetting/drying zone). As a result, we were able to study the tidal energy transformation and the role of higher harmonics in the domain in detail. For the first time, the tidal ellipses, maximum tidally induced velocities, energy fluxes and residual circulation maps were constructed and analysed for the entire bight. Additionally, tidal asymmetry maps were introduced and constructed. The full analysis was performed on two grids with different structures and showed a convergence of the results as well as fulfilment of the energy balance. A great deal of attention has been paid to the selection of open-boundary conditions, model validation against tide gauges and recent in situ current data. The tidal residual circulation and asymmetric tidal cycles largely define the circulation pattern, transport and accumulation of sediment, and the distribution of bedforms in the bight; therefore, the results presented in the article are necessary and useful benchmarks for further studies in the area, including baroclinic and sediment dynamics investigations.

Effects of Thermal Discharge from Coastal Nuclear Power Plants and Thermal Power Plants on the Thermocline Characteristics in Sea Areas with Different Tidal Dynamics

The thermal discharge from coastal nuclear power plants and thermal power plants (CNATPP) not only increases the water temperature, but it also stratifies the seawater. Comprehending the characteristics of stratification that is caused by thermal discharge constitutes the basis for developing a comprehensive understanding of how thermal discharge affects marine organisms. The spatial and temporal characteristics of seawater stratification induced by thermal discharge were analyzed on the basis of measured data while using two study areas with different tidal dynamics as examples. The results showed the following. (1) Thermal discharge influenced the area within 3 km of the outlet. (2) In the East China Sea (which has strong tidal dynamics), the most significant stratification occurred 0.5 km–1.0 km from the outlet; however, in the South China Sea (which has weak tidal dynamics), the degree of stratification decreased with increasing distance from the outlet. (3) In the East China Sea (i.e., strong tidal dynamics), the depth of the thermocline during ebb tide gradually moved upward, while that during flood tide gradually moved downward, and the opposite was observed in the South China Sea (i.e., weak tidal dynamics). Finally, (4) the thermocline that was caused by thermal discharge mostly occurred at water depths above 7 m.

Depocentre transfer in the Lingdingyang estuary: Interferences from natural and anthropogenic forcings

Estuarine morphodynamic processes caused by the combined effects of global and coastal environmental processes and human activities significantly influence the sustainable development of estuaries. Based on the bathymetric and boundary data extracted from multi-year digital charts for the Lingdingyang estuary (LE), South China, and in situ observations of the main hydrological stations, the spatiotemporal variations of depocentres in the LE and possible contributing factors are analysed. The results indicate that the spatial evolution of the morphology of the LE features shoal-deposition and channel erosion, and that the temporal evolution (1955–2015) presents a general pattern of alternating erosion and sediment deposition. A pattern of multi-depocentres exists in the LE, and the evolution of the depocentres can be divided into three general stages: i) a stage dominated by natural processes (1955–1989), ii) a stage dominated by highly-intensive reclamation (1989–2006), and iii) a stage dominated by large-scale channel dredging or sand mining (2006–2015). The transfer path of depocentres in the eastern and middle shoals traversed mainly from a north-westerly to south-easterly direction, while the transfer path of depocentres in the western shoal shows a clockwise spiral transfer feature. The large reduction of sediment supply from upstream river after the 1980s, resulted in an overall decrease in the mean annual sediment deposition volume in the LE from ~0.61 million m3/year (1989–1998) to ~0.29 million m3/year (2012–2015). The mean annual sediment deposition rate of the LE over time (i.e. 1955–2015) fluctuates in an oscillating manner rather than a linearly declining trend. Large to extreme flood (e.g. flood events of ‘94.6’, ‘98.6’ and ‘08.6’) led to higher sediment deposition rates and larger deposition volumes in the LE during the periods 1989–1998 and 2006–2008. The position of the four outlets were significantly pushed outwards by highly-intensive reclamation between 1989 and 2006, thus resulting in the bifurcation of runoff (in the Jiaomen and Hengmen outlets) and the formation of new artificial ‘outlets’ in the new channels. These great variation of the outlets induced the depocentres to transfer southeast or southwest during the period 1989–2006. A large number of temporary depocentres formed as a result of large-scale sand mining, were located in the middle shoal from 2006 to 2015. In addition, the enhancement of tidal dynamics combined with the great reduction of sediment supply from upstream river, actuated the continued transfer of the depocentres in the eastern, middle, and western shoals to the northwest or northeast after 2006. It is expected that our findings can provide a scientific foundation for port engineering construction, channel development, and the use of the tidal flat zone in the LE. Our conclusions provide a reference for other estuaries that are subject to similar anthropogenic activities.

Intratidal and Subtidal Circulation in a Tropical Estuary during Wet Season: The Maroni, French Guiana

Observations of water level, current velocity, river discharge, wind and salinity were collected in the Maroni estuary, on the border of French Guiana and Suriname during the wet season of 2018 to explore subtidal circulation patterns. Measurements are complimented by the application of analytical models with an aim to diagnose forcing mechanisms responsible for producing subtidal flows during the day of data collection and to extrapolate these findings to other time periods with variable wind and river forcing. Subtidal along-channel flows were found to be dominated by river discharge, with seaward directed velocities found throughout the channel section reaching 40 cm s − 1 . This pattern was altered with strong southwesterly winds, which produced and inverse gravitational circulation pattern despite the elevated river discharge. Secondary, or cross-channel flows, displayed a three-layer vertical structure in the main channel due to a combination of channel curvature and tidal asymmetry in the lateral baroclinic pressure gradient. The pressure gradient was produced by a salinity intrusion front that only manifested in the channel during flood tide. This is the first comprehensive study of tidal and subtidal flow dynamics in the Maroni estuary.

Spatial and seasonal variability in grain size, magnetic susceptibility, and organic elemental geochemistry of channel-bed sediments from the Mekong Delta, Vietnam: Implications for hydro-sedimentary dynamic processes

Understanding the relationship between depositional processes and their products in the fluvial–marine transition zone in tide-dominated depositional systems is fundamental to improving environmental and stratigraphic interpretations of long-term sedimentary records. The distributary channels of the Mekong Delta represent a typical example of a complex sedimentary environment characterized by strong fluvial and tidal interactions, and seasonal variability in hydro-sedimentary dynamic processes, particularly the migration of a salt wedge front linked to seasonal fluctuations in freshwater discharge. For this study, we analyzed grain size, magnetic susceptibility, and organic elemental geochemistry of channel-bed surficial sediments collected in 2015 from all distributary channels during the dry season and from the Mekong–Co Chien River during the flood season. This paper reports spatial and seasonal differences in the characteristics of channel-bed surficial sediments, which are closely linked to sediment sources and depositional processes during the dry and flood seasons.Distributary channels are characterized by coarse-grained sediments in the upper reaches and fine-grained sediments in the lower reaches, in both dry and flood seasons, reflecting the difference between the upstream fluvial-dominated environment and the downstream tide-dominated environment. Flood season samples from the Co Chien River show higher magnetic mineral contents and a terrestrial source of organic carbon compared with dry season samples, indicating sourcing from the drainage basin and trapping of suspended materials in the distributary channel due to the barrier effect of the saltwater wedge at the river mouth. Compared with the flood season, during the dry season the mud content was lower in the downstream reach close to the river mouth and higher in the upstream reach of the Co Chien River, and the content of magnetic minerals was lower in both reaches, indicating dissolution of magnetic minerals during early diagenesis. Furthermore, the lower C/N ratios (<10) and slightly enriched δ13C values of the dry season samples from the Co Chien River imply an additional contribution of organic carbon from a marine source. These various features imply a landward import of mud into the Co Chien River induced by stronger salinity intrusion during the dry season. Along the downstream tract of the Bassac River, two mud-dominated reaches were identified during the dry season. The magnetic mineral contents, C/N ratios and δ13C values indicate that the mud-dominated reach near the Bassac River mouth is also supplied from resuspended sediments by estuarine circulation and tidal pumping, whereas the mud in the reach that is transitional from fluvial to tide dominance has a riverine supply. The results suggest that the Mekong distributary channels are important sinks for suspended sediments during both the flood and dry seasons, controlled by a sediment trapping mechanism provided by either estuarine processes or the morphological configuration of the channels, both of which are controlled by fluvial–tidal dynamics. These depositional processes may be compensating for the incision of channels induced by sand mining in recent decades.

Wave effects on seedling establishment of three pioneer marsh species: survival, morphology and biomechanics.

It is important to have an in-depth mechanistic understanding of tidal marsh establishment and dynamics to ensure the long-term persistence of these valuable ecosystems. As wave forcing may be expected to impact seedling establishment, we studied the effect of water-imposed drag forces on seedling survival, morphology and biomechanical properties of three marsh pioneer species that are dominant along the salinity gradient in many areas around the world: Spartina anglica (salt to brackish), Scirpus maritimus (brackish) and Phragmites australis (brackish to fresh). Using a newly developed plant-shaking mesocosm (PSM) that mimicked water-imposed wave drag forces, the effect of wave stress on seedling survival was examined, together with impacts on morphology and biomechanical properties. After 7 weeks of exposure to wave stress, lowered seedling survival and growth for all species was revealed. Wave treatments increased the root/shoot biomass ratio to enhance anchorage and made seedlings more flexible (i.e. reduced flexural rigidity), which might be regarded as a mixed outcome between a stress avoidance and stress tolerance strategy. The different biomechanical responses between the three dominant marsh pioneer species, overall, make them less resistant to external stress. Therefore, our results indicate that the likelihood of marshes becoming established is reduced if wave energy increases. Despite the different biomechanical response of these three pioneer species to waves, the seedlings of all species were found to have low resistance to external stresses.

Assessing the relative contributions of the flood tide and the ebb tide to tidal channel network dynamics

ABSTRACTFlood and ebb currents provide different contributions to the initiation and evolution of tidal channel networks, generating diverse network structures and channel cross‐sections. In order to separate the effects of these contributions, a physical model of a sloping tidal‐flat basin was set up in the laboratory. Depending on the degree of tidal asymmetry imposed offshore, either flood or ebb currents can be enhanced. The experimental results show that the ebb current has a higher capability to initiate and shape tidal networks than the flood current. Headward erosion is mainly induced by the ebb flow. The slightly inclined flat surface tends to reduce the energy of the flood current and to enhance the ebb current, thus prolonging the duration of morphodynamic activity as well as sediment motion. Overall, flood‐dominated tides favour the formation of small‐scale channel branches in the upper basin zone, while long lasting ebb‐dominated tides result in more complex, wider and deeper tidal networks. © 2019 John Wiley &amp; Sons, Ltd.

Tidal Responses to Future Sea Level Trends on the Yellow Sea Shelf

AbstractQuantifying how tides evolve with coupling between future sea level rise (SLR) and different coastline configurations is imperative for proposing appropriate coastal defense strategies. By using numerical models, we investigated tidal changes and determined a realistic trend of SLR on the Jiangsu coastal area and adjacent sea on the Yellow Sea shelf. A notable decrease in tidal range occurs in the northern shelf, and the tide increases mainly in the southern shelf. Tidal changes are of both signs, while the increase in sea level is unidirectional. Thus, the SLR effect on tide is not additive in all locations. We also explored the nonlinearity and spatial similarity in tidal range in response to the SLR considering uniform SLR scenarios with multiple levels and allowing inundation of the natural coastline. The patterns of change in tide evolution on the study domain remain linear until the SLR exceeds 2.0 m. Simulations and comparisons are further conducted between the responses of hardened and natural shoreline configurations to SLR. Hardened shoreline introduces both local and remote spatial variability in tidal responses. On the regional scale, SLR induces a shift in the tidal system in the offshore region, which controls the net energy flux into the embayment upon the coast. On the local scale, tidal dynamics are mainly a competition between net energy flux and tidal dissipation and are plausibly influenced by tidal reflection, which depends on whether a basin is tidally reflective.