Coastal Floods Induced by Mean Sea Level Rise—Ecological and Socioeconomic Impacts on a Mesotidal Lagoon

Coastal floods are currently a strong threat to socioeconomic activities established on the margins of lagoons and estuaries, as well as to their ecological equilibrium, a situation that is expected to become even more worrying in the future in a climate change context. The Ria de Aveiro lagoon, located on the northwest coast of Portugal, is not an exception to these threats, especially considering the low topography of its margins which has led to several flood events in the past. The growing concerns with these regions stem from the mean sea level (MSL) rise induced by climate changes as well as the amplification of the impacts of storm surge events, which are predicted to increase in the future due to higher mean sea levels. Therefore, this study aims to evaluate the influence of MSL rise on the inundation of Ria de Aveiro habitats and to assess the changes in inundation patterns resulting from frequent storm surges (2-year return period) from the present to the future, assessing their ecological and socioeconomic impacts. For this, a numerical model (Delft3D), previously calibrated and validated, was used to simulate the lagoon hydrodynamics under different scenarios combining MSL rise and frequent storm surge events. The numerical results demonstrated that MSL rise can change the vertical zonation and threaten the local habitats. Many areas of the lagoon may change from supratidal/intertidal to intertidal/subtidal, with relevant consequences for local species. The increase in MSL expected for the end of the century could make the lagoon more vulnerable to the effect of frequent storm surges, harming mostly agricultural areas, causing great losses for this sector and for many communities who depend on it. These extreme events can also affect artificialized areas and, in some cases, endanger lives.

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Extremes floods of Venice: characteristics, dynamics, past and future evolution

10.5194/nhess-2020-359 ◽

2020 ◽

Author(s):

Piero Lionello ◽

David Barriopedro ◽

Christian Ferrarin ◽

Robert J. Nicholls ◽

Mirko Orlic ◽

...

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Large Range ◽

Storm Surges ◽

City Centre ◽

Atlantic Sector ◽

Mean Sea Level ◽

Sea Levels ◽

Extreme Sea Levels ◽

The Future

Abstract. Floods in the Venice city centre result from the superposition of several factors: astronomical tides, seiches and atmospherically forced fluctuations, which include storm surges, meteotsunamis, and surges caused by planetary waves. All these factors can contribute to positive sea-level anomalies individually and can also result in extreme sea-level events when they act constructively. The largest extreme sea level events have been mostly caused by storm surges produced by the Sirocco winds. This leads to a characteristic seasonal cycle, with the largest and most frequent events occurring from November to March. Storm surges can be produced by cyclones whose centers are located either north or south of the Alps. The most intense historical events have been produced by cyclogenesis in the western Mediterranean, to the west of the main cyclogenetic area of the Mediterranean region in the Gulf of Genoa. Only a small fraction of the interannual variability of extreme sea levels is described by fluctuations in the dominant patterns of atmospheric circulation variability over the Euro-Atlantic sector. Therefore, decadal fluctuations of sea-level extremes remain largely unexplained. In particular, the effect of the 11-year solar cycle appears to be small, non-stationary or masked by other factors. The historic increase in the frequency of extreme sea levels since the mid 19th Century is explained by relative sea level rise, with no long term trend in the intensity of the atmospheric forcing. Analogously, future regional relative mean sea level rise will be the most important driver of increasing duration and intensity of Venice floods through this century, overwhelming the small decrease in marine storminess projected during the 21 century. Consequently, the future increase of extreme sea levels covers a large range, partly reflecting the highly uncertain mass contributions to future mean sea level rise from the melting of Antarctica and Greenland ice-sheets, especially towards the end of the century. In conclusion, for a high emission scenario the magnitude of 1-in-100 year sea level events at the North Adriatic coast is projected to increase up to 65 % and 160 % in 2050 and 2100, respectively, with respect to the present value, and subject to continued increase thereafter. Local subsidence can further contribute to the future increase of extreme sea levels. This analysis shows the need for adaptive planning of coastal defenses with solutions that can be adopted to face the large range of plausible future sea-level extremes.

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Flooding Conditions at Aveiro Port (Portugal) within the Framework of Projected Climate Change

Journal of Marine Science and Engineering ◽

10.3390/jmse9060595 ◽

2021 ◽

Vol 9 (6) ◽

pp. 595

Author(s):

Américo Soares Ribeiro ◽

Carina Lurdes Lopes ◽

Magda Catarina Sousa ◽

Moncho Gomez-Gesteira ◽

João Miguel Dias

Keyword(s):

Climate Change ◽

Sea Level ◽

Climate Change Impacts ◽

Storm Surges ◽

Historical Period ◽

Return Periods ◽

Wave Regime ◽

Mean Sea Level ◽

Sea Levels ◽

Far Future

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures' resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges.

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Numerical Investigation of Storm Surge in Kong Port in the Persian Gulf

10.31224/osf.io/3x95p ◽

2019 ◽

Author(s):

Amir Hossein Mahdavi ◽

Hamid Ansari Sharghi

Keyword(s):

Sea Level Rise ◽

Engineering Design ◽

Sea Level ◽

Storm Surge ◽

Storm Surges ◽

Wave Model ◽

Water Level Fluctuations ◽

Extreme Value Analysis ◽

Value Analysis ◽

Mean Sea Level

Storm surge is generated by the integration of waves, tide and wind setup that is resulted in unwanted mean sea level rise and coastal flooding. The estimation of accurate storm surge is essential for the engineering design of coastal structures. In this study, we estimated the respond of mean sea level winds, tide, waves, and sea-level rise using a local coastal model. A fully coupled hydrodynamic and wave model was implemented to obtain storm surge from different phenomena. The simulations of water level fluctuations due to these parameters were analyzed with the wind forces identified with tidal observations in the Port of Kong. Extreme value analysis was performed to determine the fluctuations associated with different return periods. These data were combined by sea-level rise projections are combined with resulted value. The worst and best scenario of storm surges for each return period were determined for engineering design purposes.

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Geospatial Risk Assessment of Marine Terminal Infrastructure to Storm Surge Inundation and Sea Level Rise

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118774234 ◽

2018 ◽

Vol 2672 (11) ◽

pp. 19-29 ◽

Cited By ~ 3

Author(s):

George M. McLeod ◽

Thomas R. Allen ◽

Joshua G. Behr

Keyword(s):

Risk Assessment ◽

Sea Level Rise ◽

Sea Level ◽

Storm Surge ◽

Storm Surges ◽

Risk Tolerance ◽

Water Levels ◽

Rapid Screening ◽

Tidal Flooding ◽

The Future

Planning resiliency and sustainability of port operations and critical infrastructure requires risk assessment of storm surge exposure and potential sea level rise. An approach for rapid, screening-level assessment is developed to estimate the current and future risk of exposure to severe storm surges posed to marine terminal facilities in Norfolk, Virginia. The approach estimates the vertical elevation of local mean sea level fifty years into the future and attendant increases in potential storm surge heights. Inundation models are designed for baseline water levels and storm surges for category 1–3 hurricanes across five precautionary future sea level rise scenarios. In addition, tidal flooding poses an emerging threat because sea level rise will also force tides to higher elevations, suggesting that today’s extreme high tides may be the future mean high tide and today’s “nuisance” tidal flooding may in the future recur with chronic regularity. Potential tidal flooding levels are also modeled for each sea level scenario. This approach allows a port to assess relative risk tolerance across the range from lesser to more severe flooding events. Maps and tabular information in linked scenarios are used to summarize the extent, pattern, and depth of potential flooding. The methodology and data developed in this study may be applied to inform the timing and placement of planned assets and can be leveraged in the broader pursuit of optimization in support of long-term master planning at marine terminals.

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Impact of rising sea levels on Australian fur seals

PeerJ ◽

10.7717/peerj.5786 ◽

2018 ◽

Vol 6 ◽

pp. e5786 ◽

Cited By ~ 1

Author(s):

Lachlan J. McLean ◽

Steve George ◽

Daniel Ierodiaconou ◽

Roger J. Kirkwood ◽

John P.Y. Arnould

Keyword(s):

Sea Level ◽

Storm Surge ◽

Storm Surges ◽

Sea Levels ◽

Marine Predator ◽

Fur Seal ◽

Eastern Australia ◽

Rising Sea Levels ◽

Pup Mortality ◽

The Impact

Global warming is leading to many unprecedented changes in the ocean-climate system. Sea levels are rising at an increasing rate and are amplifying the impact of storm surges along coastlines. As variability in the timing and strength of storm surges has been shown to affect pup mortality in the Australian fur seal (Arctocephalus pusillus doriferus), there is a need to identify the potential impacts of increased sea level and storm surges on the breeding areas of this important marine predator in Bass Strait, south-eastern Australia. Using high-resolution aerial photography and topographic data, the present study assessed the impacts of future inundation levels on both current and potential breeding habitats at each colony. Inundation from storm surges, based on a predicted rise in sea level, was modeled at each colony from 2012 to 2100. As sea level increases, progressively less severe storm surge conditions will be required to exceed current inundation levels and, thus, have the potential for greater impacts on pup mortality at Australian fur seal colonies. The results of the present study indicate that by 2100, a 1-in-10 year storm will inundate more habitat on average than a present-day 1-in-100 year storm. The study highlights the site-specific nature of storm surge impacts, and in particular the importance of local colony topography and surrounding bathymetry with small, low-lying colonies impacted the most. An increased severity of storm surges will result in either an increase in pup mortality rates associated with storm surges, or the dispersal of individuals to higher ground and/or new colonies.

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Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

Natural Hazards and Earth System Science ◽

10.5194/nhess-21-2705-2021 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2705-2731 ◽

Cited By ~ 3

Author(s):

Piero Lionello ◽

David Barriopedro ◽

Christian Ferrarin ◽

Robert J. Nicholls ◽

Mirko Orlić ◽

...

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Emission Scenario ◽

Storm Surges ◽

City Centre ◽

Northern Adriatic ◽

Mean Sea Level ◽

Wide Range ◽

The Future ◽

Water Height

Abstract. Floods in the Venice city centre result from the superposition of several factors: astronomical tides; seiches; and atmospherically forced fluctuations, which include storm surges, meteotsunamis, and surges caused by atmospheric planetary waves. All these factors can contribute to positive water height anomalies individually and can increase the probability of extreme events when they act constructively. The largest extreme water heights are mostly caused by the storm surges produced by the sirocco winds, leading to a characteristic seasonal cycle, with the largest and most frequent events occurring from November to March. Storm surges can be produced by cyclones whose centres are located either north or south of the Alps. Historically, the most intense events have been produced by cyclogenesis in the western Mediterranean, to the west of the main cyclogenetic area of the Mediterranean region in the Gulf of Genoa. Only a small fraction of the inter-annual variability in extreme water heights is described by fluctuations in the dominant patterns of atmospheric circulation variability over the Euro-Atlantic sector. Therefore, decadal fluctuations in water height extremes remain largely unexplained. In particular, the effect of the 11-year solar cycle does not appear to be steadily present if more than 100 years of observations are considered. The historic increase in the frequency of floods since the mid-19th century is explained by relative mean sea level rise. Analogously, future regional relative mean sea level rise will be the most important driver of increasing duration and intensity of Venice floods through this century, overcompensating for the small projected decrease in marine storminess. The future increase in extreme water heights covers a wide range, largely reflecting the highly uncertain mass contributions to future mean sea level rise from the melting of Antarctica and Greenland ice sheets, especially towards the end of the century. For a high-emission scenario (RCP8.5), the magnitude of 1-in-100-year water height values at the northern Adriatic coast is projected to increase by 26–35 cm by 2050 and by 53–171 cm by 2100 with respect to the present value and is subject to continued increase thereafter. For a moderate-emission scenario (RCP4.5), these values are 12–17 cm by 2050 and 24–56 cm by 2100. Local subsidence (which is not included in these estimates) will further contribute to the future increase in extreme water heights. This analysis shows the need for adaptive long-term planning of coastal defences using flexible solutions that are appropriate across the large range of plausible future water height extremes.

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“Grey swan” storm surges pose a greater coastal flood hazard than climate change

Ocean Dynamics ◽

10.1007/s10236-021-01453-0 ◽

2021 ◽

Author(s):

Kevin Horsburgh ◽

Ivan D. Haigh ◽

Jane Williams ◽

Michela De Dominicis ◽

Judith Wolf ◽

...

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Storm Surges ◽

Natural Variability ◽

Major Incident ◽

Dynamical Response ◽

Mean Sea Level ◽

Coastal Flood ◽

Extreme Storm ◽

Observational Record

AbstractIn this paper, we show that over the next few decades, the natural variability of mid-latitude storm systems is likely to be a more important driver of coastal extreme sea levels than either mean sea level rise or climatically induced changes to storminess. Due to their episodic nature, the variability of local sea level response, and our short observational record, understanding the natural variability of storm surges is at least as important as understanding projected long-term mean sea level changes due to global warming. Using the December 2013 North Atlantic Storm Xaver as a baseline, we used a meteorological forecast modification tool to create “grey swan” events, whilst maintaining key physical properties of the storm system. Here we define “grey swan” to mean an event which is expected on the grounds of natural variability but is not within the observational record. For each of these synthesised storm events, we simulated storm tides and waves in the North Sea using hydrodynamic models that are routinely used in operational forecasting systems. The grey swan storms produced storm surges that were consistently higher than those experienced during the December 2013 event at all analysed tide gauge locations along the UK east coast. The additional storm surge elevations obtained in our simulations are comparable to high-end projected mean sea level rises for the year 2100 for the European coastline. Our results indicate strongly that mid-latitude storms, capable of generating more extreme storm surges and waves than ever observed, are likely due to natural variability. We confirmed previous observations that more extreme storm surges in semi-enclosed basins can be caused by slowing down the speed of movement of the storm, and we provide a novel explanation in terms of slower storm propagation allowing the dynamical response to approach equilibrium. We did not find any significant changes to maximum wave heights at the coast, with changes largely confined to deeper water. Many other regions of the world experience storm surges driven by mid-latitude weather systems. Our approach could therefore be adopted more widely to identify physically plausible, low probability, potentially catastrophic coastal flood events and to assist with major incident planning.

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Mean Sea Level as a Reference for Geodetic Leveling

The Canadian Surveyor ◽

10.1139/tcs-1974-0095 ◽

1974 ◽

Vol 28 (5) ◽

pp. 524-530 ◽

Cited By ~ 3

Author(s):

G. W. Lennon

Keyword(s):

Sea Level ◽

World Ocean ◽

Equipotential Surface ◽

Scientific Discipline ◽

Mean Sea Level ◽

Sea Levels ◽

Coastal Sea ◽

Long Time ◽

Marine System

The use of mean sea level as a surface of reference that might provide an independent control for geodetic leveling has been a long term goal arising from the classical analogy between the geoid as an equipotential surface and the surface assumed by a hypothetical undisturbed world ocean. The problems associated with this aim are now known to be vast, and are associated with the dynamics of the marine system, notably its response to meteorological forces, to variations in density and to the effects of basic circulation patterns. In consequence the mean sea level surface varies rapidly in both time and space. This identifies in fact a distinctive scientific discipline, coastal geodesy, in which contributions are required by both geodesists and oceanographers. It has come to be recognized that the coastal zone is a hazardous environment for all observational techniques concerned. On the one hand, the difficulties of measurement of coastal sea levels have only recently been understood; on the other hand, precise leveling procedures are now known to be influenced by the attraction of marine tides and by crustal deformation of tidal loading. Much of the data available for study are therefore inadequate and, moreover, it should be noted that long-time series are required. It is now possible to lay plans for both geodetic and oceanographic procedures to remedy these deficiencies in the long-term interests of the study.

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Extreme Storm Surge estimates and projection through the Metastatistical Extreme Value Distribution

10.5194/egusphere-egu21-10706 ◽

2021 ◽

Author(s):

Maria Francesca Caruso ◽

Marco Marani

Keyword(s):

Sea Level ◽

Extreme Value Distribution ◽

Storm Surges ◽

Extreme Value ◽

Value Distribution ◽

Generalized Extreme Value Distribution ◽

Sample Sizes ◽

Mean Sea Level ◽

Gev Distribution ◽

Calibration Sample

Storm surges caused by extreme meteorological conditions are a major natural risk in coastal areas, especially in the context of global climate change. The increase of future sea-levels caused by continuing global warming, may endanger human lives and infrastructure through inundation, erosion and salinization. Hence, the reliable estimation of the occurrence probability of these extreme events is crucial to quantify risk and to design adequate coastal defense structures. The probability of event occurrence is typically estimated by modelling observed sea-level records using one of a few statistical approaches. The traditional Extreme Value Theory is based on the use of the Generalized Extreme Value distribution (GEV), &#160;fitted either by considering block (typically yearly) maxima, or values exceeding a high threshold (POT). This approach does not make full use of all observational information, and thereby does not minimize estimation uncertainty. The recently proposed Metastatistical Extreme Value Distribution (MEVD), instead, makes use of most of the available observations and has been shown to outperform the classical GEV distribution in several applications, including hourly and daily rainfall, flood peak discharge and extreme hurricane intensity. Here, we comparatively apply the MEVD and the GEV distribution to long time series of sea-level observations distributed along European coastlines (Venice (IT), Hornbaek (DK), Marseille (FR), Newlyn (UK)). A cross-validation approach, dividing available data in separate calibration and test sub-samples, is used to compare their performances in high-quantile estimation. The MEVD approach is based on the definition of an &#8220;ordinary values&#8221; distribution (here a Generalized Pareto distribution), whose parameters are estimated using the Probability Weighted Moments method on non-overlapping sub-samples of fixed size (5 years). To address the problems posed by observational samples of different sizes, we explore the effect on uncertainty of different calibration sample sizes, from 5 to 30 years. In this application, we find that the GEVD-POT and MEVD approaches perform similarly, once the above parameter choices are optimized. In particular, when considering short samples (5 years) and events with a high return time, the estimation errors show no significant differences in their median value across methods and sites, all approaches producing a similar underestimation of the actual quantile. When larger calibration sample sizes are considered (10-30 yrs), the median error of MEVD estimates tends to be closer to zero than those obtained from the traditional methods. Future projections of sea-level rise until 2100 are also analyzed, with reference to intermediate and extreme representative concentration pathways (RCP 4.5 and RCP 8.5). The probability of future storm surges along European coastlines are then estimated assuming a changing mean sea-level and an unchanged storm regime. The projections indicate future changes in mean sea-level lead to increases in the height of storm surges for a fixed return period that are spatially heterogeneous across the coastal locations explored.

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APPLICABILITY OF THE VERTICAL TELESCOPIC BREAKWATER USING THE PAST TYPHOON IN TOKYO BAY

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.structures.35 ◽

2020 ◽

pp. 35

Author(s):

Yako Harada ◽

Yukihisa Matsumoto ◽

Kazuho Morishita ◽

Nobuyuki Oonishi ◽

Kazuyoshi Kihara ◽

...

Keyword(s):

Climate Change ◽

Storm Surge ◽

Storm Surges ◽

Numerical Calculations ◽

Numerical Analyses ◽

Tokyo Bay ◽

Worst Case ◽

Sea Levels ◽

Long Period ◽

The Past

The vertical telescopic breakwater(VTB), which is a new breakwater that permits the navigation of ships, remain at the bottom of the sea during calm and rise to the surface during tsunamis or storm surges. Kawai et al. (2017) and Arikawa et al. (2019) found that it is effective not only for swell waves, but also for long-period waves simulating tsunamis and storm surges by previous experiments and numerical analyses. However, there have been few studies on the performance of VTB by numerical calculations in actual ports using actual typhoons. In addition, sea levels and changes in characteristics of typhoon due to climate change are predicted to occur; hence, we are concerned about the damage in all quarters caused by storm surge inundation, especially at Tokyo. Therefore, in this study, we used hypothetical typhoons under worst-case scenarios and quantitatively evaluated the protection performance of VTB against hypothetical typhoons with different aperture rates of VTB in Tokyo Bay by the numerical simulation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/qof5ixKqIiA

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