Challenges of Sea-level Rise on Estuarine Tidal Dynamics

2022 ◽  
pp. 45-58
Author(s):  
Danial Khojasteh ◽  
Jamie Ruprecht ◽  
Katrina Waddington ◽  
Hamed Moftakhari ◽  
Amir AghaKouchak ◽  
...  
2020 ◽  
pp. 103166 ◽  
Author(s):  
Danial Khojasteh ◽  
William Glamore ◽  
Valentin Heimhuber ◽  
Stefan Felder

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Caroline Rasquin ◽  
Rita Seiffert ◽  
Benno Wachler ◽  
Norbert Winkel

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.


2020 ◽  
Vol 4 (1) ◽  
pp. 93-105
Author(s):  
Ali Abdulridha Lafta ◽  
Samer Adnan Altaei ◽  
Noori Hussain Al-Hashimi

2019 ◽  
Author(s):  
Caroline Rasquin ◽  
Rita Seiffert ◽  
Benno Wachler ◽  
Norbert Winkel

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 flat coastal areas, especially the German Bight (located in the south-east of the North Sea) will be affected. Numerical hydrodynamic models help to understand how mean sea level rise changes tidal dynamics. By definition models cannot 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 m and 10 m. To the mean sea level rise of 0.8 m the shelf model and the German Bight Model react in different ways. In the shelf model the M2 amplitude 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 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 in the order of 1 m. For higher mean sea level rise scenarios (10 m) the resolution of the bathymetry is less important.


2021 ◽  
Author(s):  
Tara Mahavadi ◽  
Elisabeth Rudolph ◽  
Rita Seiffert ◽  
Norbert Winkel

<p>Future mean sea level rise will influence tidal dynamics and storm surge events in estuaries. The bathymetry in estuaries and coastal areas will also be affected by mean sea level rise, since it is in a morphodynamic equilibrium with hydrodynamic forces. Tidal flats, which are an important component of coastal protection, will grow to a certain extent with mean sea level rise in case of sufficient sediment availability.</p><p>With the help of a highly resolved hydrodynamic-numerical model of the German Bight (North Sea), we analyse the potential influence of mean sea level rise and vertical growth of tidal flats on tidal dynamics and storm surge events in the Elbe estuary.</p><p>The results show an increase of tidal amplitude and storm surge water levels due to mean sea level rise. A bathymetric rise of tidal flats in the German Bight and the mouth of the Elbe estuary leads to a decrease in storm surge water level and tidal amplitude compared to the scenario with sole mean sea level rise without a change in bathymetry. Further analyses show, how geometric parameters of the Elbe estuary are changing due to mean sea level rise and tidal flat growth. These changes in geometry influence tidal dynamics and can therefore be an explanation for the observed changes in tidal amplitude and storm surge water levels.</p><p>These findings enable a better understanding of future changes in the Elbe estuary and support coastal managers in decision making processes concerning adaptation options to reduce the impacts of climate change.</p>


2014 ◽  
Vol 44 (5) ◽  
pp. 1439-1455 ◽  
Author(s):  
Rusty C. Holleman ◽  
Mark T. Stacey

Abstract With the global sea level rising, it is imperative to quantify how the dynamics of tidal estuaries and embayments will respond to increased depth and newly inundated perimeter regions. With increased depth comes a decrease in frictional effects in the basin interior and altered tidal amplification. Inundation due to higher sea level also causes an increase in planform area, tidal prism, and frictional effects in the newly inundated areas. To investigate the coupling between ocean forcing, tidal dynamics, and inundation, the authors employ a high-resolution hydrodynamic model of San Francisco Bay, California, comprising two basins with distinct tidal characteristics. Multiple shoreline scenarios are simulated, ranging from a leveed scenario, in which tidal flows are limited to present-day shorelines, to a simulation in which all topography is allowed to flood. Simulating increased mean sea level, while preserving original shorelines, produces additional tidal amplification. However, flooding of adjacent low-lying areas introduces frictional, intertidal regions that serve as energy sinks for the incident tidal wave. Net tidal amplification in most areas is predicted to be lower in the sea level rise scenarios. Tidal dynamics show a shift to a more progressive wave, dissipative environment with perimeter sloughs becoming major energy sinks. The standing wave southern reach of the bay couples more strongly back to the central portion of the bay, in contrast to the progressive wave northern reach of the bay. Generation of the M4 overtide is also found to vary between scenarios and is a nonnegligible contributor to net changes in high water elevation.


2021 ◽  
Vol 8 ◽  
Author(s):  
Christian Jordan ◽  
Jan Visscher ◽  
Torsten Schlurmann

This study explores the projected responses of tidal dynamics in the North Sea induced by the interplay between plausible projections of sea-level rise (SLR) and morphological changes in the Wadden Sea. This is done in order to gain insight into the casual relationships between physical drivers and hydro-morphodynamic processes. To achieve this goal, a hydronumerical model of the northwest European shelf seas (NWES) was set-up and validated. By implementing a plausible set of projections for global SLR (SLRRCP8.5 of 0.8 m and SLRhigh−end of 2.0 m) by the end of this century and beyond, the model was run to assess the responses of the regional tidal dynamics. In addition, for each considered SLR, various projections for cumulative rates of vertical accretion were applied to the intertidal flats in the Wadden Sea (ranging from 0 to 100% of projected SLR). Independent of the rate of vertical accretion, the spatial pattern of M2 amplitude changes remains relatively stable throughout most of the model domain for a SLR of 0.8 m. However, the model shows a substantial sensitivity toward the different rates of vertical accretion along the coasts of the Wadden Sea, but also in remote regions like the Skagerrak. If no vertical accretion is assumed in the intertidal flats of the Wadden Sea, the German Bight and the Danish west coast are subject to decreases in M2 amplitudes. In contrast, those regions experience increases in M2 amplitudes if the local intertidal flats are able to keep up with the projected SLR of 0.8 m. Between the different scenarios, the North Frisian Wadden Sea shows the largest differences in M2 amplitudes, locally varying by up to 14 cm. For a SLR of 2.0 m, the M2 amplitude changes are even more amplified. Again, the differences between the various rates of vertical accretion are largest in the North Frisian Wadden Sea (> 20 cm). The local distortion of the tidal wave is also significantly different between the scenarios. In the case of no vertical accretion, tidal asymmetry in the German estuaries increases, leading to a potentially enhanced sediment import. The presented results have strong implications for local coastal protection strategies and navigation in adjacent estuaries.


Author(s):  
Danial Khojasteh ◽  
Steve Hottinger ◽  
Stefan Felder ◽  
Giovanni De Cesare ◽  
Valentin Heimhuber ◽  
...  

Worldwide, hundreds of millions of people who live on or near estuarine environments are vulnerable to sea level rise (SLR). Using clustering techniques and moving beyond static models and case studies, this study used a large ensemble of idealised estuary models of varying scale, geometry, level of entrance constriction, and SLR scenarios. It was found that tidal forcing, degree of entrance restriction, and estuarine length can primarily control the tidal dynamics of prismatic estuaries under SLR. Further, restricting an entrance can be presented as a potential solution to offset SLR induced tidal amplification if the associated impacts on entrance stability, navigation, and flooding are considered.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vOptOAbqN3U


Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Kate Wheeling

Researchers identify the main sources of uncertainty in projections of global glacier mass change, which is expected to add about 8–16 centimeters to sea level, through this century.


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