Articles | Volume 22, issue 1
https://doi.org/10.5194/nhess-22-187-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/nhess-22-187-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 Jan 2022
Research article |
| 28 Jan 2022
| 28 Jan 2022
Investigating the interaction of waves and river discharge during compound flooding at Breede Estuary, South Africa
Sunna Kupfer
CORRESPONDING AUTHOR
Coastal Risks and Sea-Level Rise Research Group, Department of Geography, Christian-Albrechts University, Kiel, Germany
Sara Santamaria-Aguilar
Coastal Risks and Sea-Level Rise Research Group, Department of Geography, Christian-Albrechts University, Kiel, Germany
Lara van Niekerk
Coastal Systems Research Group, Council for Scientific and Industrial Research CSIR, Stellenbosch, 7600, South Africa
Institute for Coastal and Marine Research, Nelson Mandela University, P.O. Box 77000, Port Elizabeth, 6031, South Africa
Melanie Lück-Vogel
Coastal Systems Research Group, Council for Scientific and Industrial Research CSIR, Stellenbosch, 7600, South Africa
Department for Geography and Environmental Studies, Stellenbosch University, Stellenbosch, 7600, South Africa
Athanasios T. Vafeidis
Coastal Risks and Sea-Level Rise Research Group, Department of Geography, Christian-Albrechts University, Kiel, Germany
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Pravin Maduwantha, Thomas Wahl, Sara Santamaria-Aguilar, Robert Andrew Jane, James F. Booth, Hanbeen Kim, and Gabriele Villarini
EGUsphere, https://doi.org/10.5194/egusphere-2024-1122, https://doi.org/10.5194/egusphere-2024-1122, 2024
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Most of the studies on compound flooding assume events that generate extreme rainfall and coastal water level responses originate from a single population, in reality, they originate from multiple populations each with unique statistical characteristics. This paper presents a flexible statistical framework for assessing the compound flood potential from multiple flood drivers that explicitly accounts for different event types.
Giulia Galluccio, Alexander Bisaro, Elisa Fiorini Beckauser, Rebeca Biancardi Aleu, Jochen Hinkel, Maria Florencia Casas, Océane Espin, Athanasios Thomas Vafeidis, and Pierpaolo Campostrini
State Planet Discuss., https://doi.org/10.5194/sp-2023-35, https://doi.org/10.5194/sp-2023-35, 2024
Revised manuscript accepted for SP
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The paper synthesizes scientific knowledge on SLR in Europe, guiding evidence-based policy. SLR poses challenges for coastal decision-making addressed through a mix of hard and soft strategies across sea basins: incorporation of SLR projections into spatial planning, focus on adaptation plans and nature-based solutions, priorization of early warning systems . The review stresses key coastal adaptation considerations, as flexibility, integration of SLR information, and iterative decision-making.
Joshua Kiesel, Marvin Lorenz, Marcel König, Ulf Gräwe, and Athanasios T. Vafeidis
Nat. Hazards Earth Syst. Sci., 23, 2961–2985, https://doi.org/10.5194/nhess-23-2961-2023, https://doi.org/10.5194/nhess-23-2961-2023, 2023
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Among the Baltic Sea littoral states, Germany is anticipated to experience considerable damage as a result of increased coastal flooding due to sea-level rise (SLR). Here we apply a new modelling framework to simulate how flooding along the German Baltic Sea coast may change until 2100 if dikes are not upgraded. We find that the study region is highly exposed to flooding, and we emphasise the importance of current plans to update coastal protection in the future.
Athanasios T. Vafeidis, Mark Schuerch, Claudia Wolff, Tom Spencer, Jan L. Merkens, Jochen Hinkel, Daniel Lincke, Sally Brown, and Robert J. Nicholls
Nat. Hazards Earth Syst. Sci., 19, 973–984, https://doi.org/10.5194/nhess-19-973-2019, https://doi.org/10.5194/nhess-19-973-2019, 2019
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This paper evaluates the effect of surge water level reduction due to land surface characteristics when assessing flood impacts at global scales. Our results show that uncertainties due to not accounting for water attenuation are of similar magnitude to the uncertainties regarding the total amount of sea-level rise expected by 2100, thus highlighting the need for better understanding of the spatial and temporal variation of water levels across floodplains.
Kristian Kumbier, Rafael C. Carvalho, Athanasios T. Vafeidis, and Colin D. Woodroffe
Nat. Hazards Earth Syst. Sci., 18, 463–477, https://doi.org/10.5194/nhess-18-463-2018, https://doi.org/10.5194/nhess-18-463-2018, 2018
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This study investigates compound flooding in an estuary by quantifying horizontal (flood extent) and vertical differences (inundation depth) in flood risk estimates resulting from a separation of storm surge and river flooding. Results demonstrated large underestimation of flood risk when river discharge was excluded. We recommend considering storm surge and river flooding processes jointly in estuaries with large catchment areas which are known to have a quick response time to extreme rainfall.
Athanasios T. Vafeidis, Mark Schuerch, Claudia Wolff, Tom Spencer, Jan L. Merkens, Jochen Hinkel, Daniel Lincke, Sally Brown, and Robert J. Nicholls
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2017-199, https://doi.org/10.5194/nhess-2017-199, 2017
Manuscript not accepted for further review
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Global assessments of coastal flooding are based on the assumption that water propagation follows a
bathtubpattern across the floodplain. Using a global model we find that this assumption can lead to overestimation of impacts, with an uncertainty range that can be of equal magnitude to uncertainties related to future sea-level rise. Our results highlight the importance of improving the representation of the spatial/temporal variation of water levels across floodplains of different landcover.
Related subject area
Sea, Ocean and Coastal Hazards
Brief communication: Implications of outstanding solitons for the occurrence of rogue waves at two additional sites in the North Sea
A systemic and comprehensive assessment of coastal hazard changes: method and application to France and its overseas territories
Simulating sea level extremes from synthetic low-pressure systems
Nonlinear processes in tsunami simulations for the Peruvian coast with focus on Lima and Callao
The potential of global coastal flood risk reduction using various DRR measures
Modeling tsunami initial conditions due to rapid coseismic seafloor displacement: efficient numerical integration and a tool to build unit source databases
Thresholds for estuarine compound flooding using a combined hydrodynamic–statistical modelling approach
Nearshore tsunami amplitudes across the Maldives archipelago due to worst-case seismic scenarios in the Indian Ocean
Evidence of Middle Holocene landslide-generated tsunamis recorded in lake sediments from Saqqaq, West Greenland
Investigation of historical severe storms and storm tides in the German Bight with century reanalysis data
Revisiting regression methods for estimating long-term trends in sea surface temperature
The impact of long-term changes in ocean waves and storm surge on coastal shoreline change: A case study of Bass Strait and south-east Australia
Tsunami Hazard Assessment in the South China Sea Based on Geodetic Locking of the Manila Subduction Zone
Proposal for a new meteotsunami intensity index
Total water levels along the South Atlantic Bight during three along-shelf propagating tropical cyclones: relative contributions of storm surge and wave runup
Hurricane Irma: an unprecedented event over the last 3700 years? Geomorphological changes and sedimentological record in Codrington Lagoon, Barbuda
Bayesian extreme value analysis of extreme sea levels along the German Baltic coast using historical information
Storm characteristics influence nitrogen removal in an urban estuarine environment
A new European coastal flood database for low–medium intensity events
Boulder transport and wave height of a seventeenth-century South China Sea tsunami on Penghu Islands, Taiwan
A wave-resolving modeling study of rip current variability, rip hazard, and swimmer escape strategies on an embayed beach
Human displacements from Tropical Cyclone Idai attributable to climate change
Global application of a regional frequency analysis on extreme sea levels
Estuarine hurricane wind can intensify surge-dominated extreme water level in shallow and converging coastal systems
Influence of data source and copula statistics on estimates of compound extreme water levels in a river mouth environment
Three decades of coastal subsidence in the slow-moving Nice Côte d'Azur Airport area (France) revealed by InSAR (interferometric synthetic-aperture radar): insights into the deformation mechanism
Modelling extreme water levels using intertidal topography and bathymetry derived from multispectral satellite images
Regional assessment of extreme sea levels and associated coastal flooding along the German Baltic Sea coast
Joint probability analysis of storm surges and waves caused by tropical cyclones for the estimation of protection standard: a case study on the eastern coast of the Leizhou Peninsula and the island of Hainan in China
Meteotsunami in the United Kingdom: the hidden hazard
Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region
Assessing Typhoon Soulik-induced morphodynamics over the Mokpo coastal region in South Korea based on a geospatial approach
Bayesian hierarchical modelling of sea-level extremes in the Finnish coastal region
Assessing the coastal hazard of Medicane Ianos through ensemble modelling
A predictive equation for wave setup using genetic programming
Contribution of solitons to enhanced rogue wave occurrence in shallow depths: a case study in the southern North Sea
Compound flood events: analysing the joint occurrence of extreme river discharge events and storm surges in northern and central Europe
Improvements to the detection and analysis of external surges in the North Sea
Optimal probabilistic placement of facilities using a surrogate model for 3D tsunami simulations
Enabling dynamic modelling of coastal flooding by defining storm tide hydrographs
The role of preconditioning for extreme storm surges in the western Baltic Sea
Freak wave events in 2005–2021: statistics and analysis of favourable wave and wind conditions
Probabilistic projections and past trends of sea level rise in Finland
The effect of deep ocean currents on ocean- bottom seismometers records
An interdisciplinary agent-based evacuation model: integrating the natural environment, built environment, and social system for community preparedness and resilience
Coastal extreme sea levels in the Caribbean Sea induced by tropical cyclones
Characteristics of consecutive tsunamis and resulting tsunami behaviors in southern Taiwan induced by the Hengchun earthquake doublet on 26 December 2006
Potential tsunami hazard of the southern Vanuatu subduction zone: tectonics, case study of the Matthew Island tsunami of 10 February 2021 and implication in regional hazard assessment
Detecting anomalous sea-level states in North Sea tide gauge data using an autoassociative neural network
Observations of extreme wave runup events on the US Pacific Northwest coast
Ina Teutsch, Ralf Weisse, and Sander Wahls
Nat. Hazards Earth Syst. Sci., 24, 2065–2069, https://doi.org/10.5194/nhess-24-2065-2024, https://doi.org/10.5194/nhess-24-2065-2024, 2024
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We investigate buoy and radar measurement data from shallow depths in the southern North Sea. We analyze the role of solitons for the occurrence of rogue waves. This is done by computing the nonlinear soliton spectrum of each time series. In a previous study that considered a single measurement site, we found a connection between the shape of the soliton spectrum and the occurrence of rogue waves. In this study, results for two additional sites are reported.
Marc Igigabel, Marissa Yates, Michalis Vousdoukas, and Youssef Diab
Nat. Hazards Earth Syst. Sci., 24, 1951–1974, https://doi.org/10.5194/nhess-24-1951-2024, https://doi.org/10.5194/nhess-24-1951-2024, 2024
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Changes in sea levels alone do not determine the evolution of coastal hazards. Coastal hazard changes should be assessed using additional factors describing geomorphological configurations, metocean event types (storms, cyclones, long swells, and tsunamis), and the marine environment (e.g., coral reef state and sea ice extent). The assessment completed here, at regional scale including the coasts of mainland and overseas France, highlights significant differences in hazard changes.
Jani Särkkä, Jani Räihä, Mika Rantanen, and Matti Kämäräinen
Nat. Hazards Earth Syst. Sci., 24, 1835–1842, https://doi.org/10.5194/nhess-24-1835-2024, https://doi.org/10.5194/nhess-24-1835-2024, 2024
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We study the relationship between tracks of low-pressure systems and related sea level extremes. We perform the studies by introducing a method to simulate sea levels using synthetic low-pressure systems. We test the method using sites located along the Baltic Sea coast. We find high extremes, where the sea level extreme reaches up to 3.5 m. In addition, we add the maximal value of the mean level of the Baltic Sea (1 m), leading to a sea level of 4.5 m.
Alexey Androsov, Sven Harig, Natalia Zamora, Kim Knauer, and Natalja Rakowsky
Nat. Hazards Earth Syst. Sci., 24, 1635–1656, https://doi.org/10.5194/nhess-24-1635-2024, https://doi.org/10.5194/nhess-24-1635-2024, 2024
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Two numerical codes are used in a comparative analysis of the calculation of the tsunami wave due to an earthquake along the Peruvian coast. The comparison primarily evaluates the flow velocity fields in flooded areas. The relative importance of the various parts of the equations is determined, focusing on the nonlinear terms. The influence of the nonlinearity on the degree and volume of flooding, flow velocity, and small-scale fluctuations is determined.
Eric Mortensen, Timothy Tiggeloven, Toon Haer, Bas van Bemmel, Dewi Le Bars, Sanne Muis, Dirk Eilander, Frederiek Sperna Weiland, Arno Bouwman, Willem Ligtvoet, and Philip J. Ward
Nat. Hazards Earth Syst. Sci., 24, 1381–1400, https://doi.org/10.5194/nhess-24-1381-2024, https://doi.org/10.5194/nhess-24-1381-2024, 2024
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Current levels of coastal flood risk are projected to increase in coming decades due to various reasons, e.g. sea-level rise, land subsidence, and coastal urbanization: action is needed to minimize this future risk. We evaluate dykes and coastal levees, foreshore vegetation, zoning restrictions, and dry-proofing on a global scale to estimate what levels of risk reductions are possible. We demonstrate that there are several potential adaptation pathways forward for certain areas of the world.
Alice Abbate, José M. González Vida, Manuel J. Castro Díaz, Fabrizio Romano, Hafize Başak Bayraktar, Andrey Babeyko, and Stefano Lorito
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2024-41, https://doi.org/10.5194/nhess-2024-41, 2024
Revised manuscript under review for NHESS
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Modeling the tsunami generation due to a rapid submarine earthquake is a complex problem. We propose and test, under a variety of realistic conditions in a subduction zone, an efficient solution to this problem, and a tool which can compute the generation of any potential tsunami in any ocean of the world. We will explore in the future solutions which would allow us to model the tsunami generation also by slower (time-dependent) seafloor displacement.
Charlotte Lyddon, Nguyen Chien, Grigorios Vasilopoulos, Michael Ridgill, Sogol Moradian, Agnieszka Olbert, Thomas Coulthard, Andrew Barkwith, and Peter Robins
Nat. Hazards Earth Syst. Sci., 24, 973–997, https://doi.org/10.5194/nhess-24-973-2024, https://doi.org/10.5194/nhess-24-973-2024, 2024
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Recent storms in the UK, like Storm Ciara in 2020, show how vulnerable estuaries are to the combined effect of sea level and river discharge. We show the combinations of sea levels and river discharges that cause flooding in the Conwy estuary, N Wales. The results showed flooding was amplified under moderate conditions in the middle estuary and elsewhere sea state or river flow dominated the hazard. Combined sea and river thresholds can improve prediction and early warning of compound flooding.
Shuaib Rasheed, Simon C. Warder, Yves Plancherel, and Matthew D. Piggott
Nat. Hazards Earth Syst. Sci., 24, 737–755, https://doi.org/10.5194/nhess-24-737-2024, https://doi.org/10.5194/nhess-24-737-2024, 2024
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Here we use a high-resolution bathymetry dataset of the Maldives archipelago, as well as corresponding high numerical model resolution, to carry out a scenario-based tsunami hazard assessment for the entire Maldives archipelago to investigate the potential impact of plausible far-field tsunamis across the Indian Ocean at the island scale. The results indicate that several factors contribute to mitigating and amplifying tsunami waves at the island scale.
Niels J. Korsgaard, Kristian Svennevig, Anne S. Søndergaard, Gregor Luetzenburg, Mimmi Oksman, and Nicolaj K. Larsen
Nat. Hazards Earth Syst. Sci., 24, 757–772, https://doi.org/10.5194/nhess-24-757-2024, https://doi.org/10.5194/nhess-24-757-2024, 2024
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A tsunami wave will leave evidence of erosion and deposition in coastal lakes, making it possible to determine the runup height and when it occurred. Here, we use four lakes now located at elevations of 19–91 m a.s.l. close to the settlement of Saqqaq, West Greenland, to show that at least two giant tsunamis occurred 7300–7600 years ago with runup heights larger than 40 m. We infer that any tsunamis from at least nine giga-scale landslides must have happened 8500–10 000 years ago.
Elke Magda Inge Meyer and Lidia Gaslikova
Nat. Hazards Earth Syst. Sci., 24, 481–499, https://doi.org/10.5194/nhess-24-481-2024, https://doi.org/10.5194/nhess-24-481-2024, 2024
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Storm tides for eight extreme historical storms in the German Bight are modelled using sets of slightly varying atmospheric conditions from the century reanalyses. Comparisons with the water level observations from the gauges Norderney, Cuxhaven and Husum show that single members of the reanalyses are suitable for the reconstruction of extreme storms. Storms with more northerly tracks show less variability within a set and have more potential for accurate reconstruction of extreme water levels.
Ming-Huei Chang, Yen-Chen Huang, Yu-Hsin Cheng, Chuen-Teyr Terng, Jinyi Chen, and Jyh Cherng Jan
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2023-218, https://doi.org/10.5194/nhess-2023-218, 2024
Revised manuscript accepted for NHESS
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Monitoring the long-term trends in sea surface warming is crucial for informed decision-making and adaptation. This study offers a comprehensive examination of prevalent trend extraction methods. We identify ordinary least squares as suitable for general tasks yet highlight the need to address seasonal signal-induced bias, specifically the phase-distance imbalance. Our implementation, evaluated with simulated and realist data, provides a potential solution.
Mandana Ghanavati, Ian Young, Ebru Kirezci, and Jin Liu
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2023-205, https://doi.org/10.5194/nhess-2023-205, 2024
Revised manuscript accepted for NHESS
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The paper examines the changes in shoreline position of the coast of south-east Australia over a 26 year period to determine if changes are consistent with observed changes in ocean wave and storm surge climate. The results show that in regions where there have been significant changes in wave energy flux or wave direction there have been changes in shoreline position consistent with non-equilibrium longshore drift.
Guangsheng Zhao and Xiaojing Niu
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2023-227, https://doi.org/10.5194/nhess-2023-227, 2024
Revised manuscript accepted for NHESS
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The purpose of this study is to estimate the spatial distribution of the tsunami hazard in the South China Sea from the Manila subduction zone. The plate motion data is used to invert the degree of locking on the fault plane. The degree of locking is used to estimate the maximum possible magnitude of earthquakes and describe the slip distribution. A spatial distribution map of the 1000-year return period tsunami wave height in the South China Sea was obtained by tsunami hazard assessment.
Clare Lewis, Tim Smyth, Jess Neumann, and Hannah Cloke
Nat. Hazards Earth Syst. Sci., 24, 121–131, https://doi.org/10.5194/nhess-24-121-2024, https://doi.org/10.5194/nhess-24-121-2024, 2024
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Meteotsunami are the result of atmospheric disturbances and can impact coastlines causing injury, loss of life, and damage to assets. This paper introduces a novel intensity index to allow for the quantification of these events at the shoreline. This has the potential to assist in the field of natural hazard assessment. It was trialled in the UK but designed for global applicability and to become a widely accepted standard in coastal planning, meteotsunami forecasting, and early warning systems.
Chu-En Hsu, Katherine A. Serafin, Xiao Yu, Christie A. Hegermiller, John C. Warner, and Maitane Olabarrieta
Nat. Hazards Earth Syst. Sci., 23, 3895–3912, https://doi.org/10.5194/nhess-23-3895-2023, https://doi.org/10.5194/nhess-23-3895-2023, 2023
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Total water levels (TWLs) induced by tropical cyclones (TCs) are among the leading hazards faced by coastal communities. Using numerical models, we examined how TWL components (surge and wave runup) along the South Atlantic Bight varied during hurricanes Matthew (2016), Dorian (2019), and Isaias (2020). Peak surge and peak wave runup were dominated by wind speeds and relative positions to TCs. The exceedance time of TWLs was controlled by normalized distances to TC and TC translation speeds.
Maude Biguenet, Eric Chaumillon, Pierre Sabatier, Antoine Bastien, Emeline Geba, Fabien Arnaud, Thibault Coulombier, and Nathalie Feuillet
Nat. Hazards Earth Syst. Sci., 23, 3761–3788, https://doi.org/10.5194/nhess-23-3761-2023, https://doi.org/10.5194/nhess-23-3761-2023, 2023
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This work documents the impact of Hurricane Irma (2017) on the Codrington barrier and lagoon on Barbuda Island. Irma caused two wide breaches in the sandy barrier, which remained unopened for 250 years. The thick and extensive sand sheet at the top of the lagoon fill was attributed to Irma. This unique deposit in a 3700-year record confirms Irma's exceptional character. This case study illustrates the consequences of high-intensity hurricanes in low-lying islands in a global warming context.
Leigh Richard MacPherson, Arne Arns, Svenja Fischer, Fernando Javier Méndez, and Jürgen Jensen
Nat. Hazards Earth Syst. Sci., 23, 3685–3701, https://doi.org/10.5194/nhess-23-3685-2023, https://doi.org/10.5194/nhess-23-3685-2023, 2023
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Efficient adaptation planning for coastal flooding caused by extreme sea levels requires accurate assessments of the underlying hazard. Tide-gauge data alone are often insufficient for providing the desired accuracy but may be supplemented with historical information. We estimate extreme sea levels along the German Baltic coast and show that relying solely on tide-gauge data leads to underestimations. Incorporating historical information leads to improved estimates with reduced uncertainties.
Anne Margaret H. Smiley, Suzanne P. Thompson, Nathan S. Hall, and Michael F. Piehler
Nat. Hazards Earth Syst. Sci., 23, 3635–3649, https://doi.org/10.5194/nhess-23-3635-2023, https://doi.org/10.5194/nhess-23-3635-2023, 2023
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Floodwaters can deliver reactive nitrogen to sensitive aquatic systems and diminish water quality. We assessed the nitrogen removal capabilities of flooded habitats and urban landscapes. Differences in processing rates across land cover treatments and between nutrient treatments suggest that abundance and spatial distributions of habitats, as well as storm characteristics, influence landscape-scale nitrogen removal. Results have important implications for coastal development and climate change.
Marine Le Gal, Tomás Fernández-Montblanc, Enrico Duo, Juan Montes Perez, Paulo Cabrita, Paola Souto Ceccon, Véra Gastal, Paolo Ciavola, and Clara Armaroli
Nat. Hazards Earth Syst. Sci., 23, 3585–3602, https://doi.org/10.5194/nhess-23-3585-2023, https://doi.org/10.5194/nhess-23-3585-2023, 2023
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Assessing coastal hazards is crucial to mitigate flooding disasters. In this regard, coastal flood databases are valuable tools. This paper describes a new coastal flood map catalogue covering the entire European coastline, as well as the methodology to build it and its accuracy. The catalogue focuses on frequent extreme events and relies on synthetic scenarios estimated from local storm conditions. Flood-prone areas and regions sensitive to storm duration and water level peak were identified.
Neng-Ti Yu, Cheng-Hao Lu, I-Chin Yen, Jia-Hong Chen, Jiun-Yee Yen, and Shyh-Jeng Chyi
Nat. Hazards Earth Syst. Sci., 23, 3525–3542, https://doi.org/10.5194/nhess-23-3525-2023, https://doi.org/10.5194/nhess-23-3525-2023, 2023
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A paleotsunami deposit of cliff-top basalt debris was identified on the Penghu Islands in the southern Taiwan Strait and related to the 1661 earthquake in southwest Taiwan. A minimum wave height of 3.2 m is estimated to have rotated the biggest boulder for over 30 m landwards onto the cliff top at 2.5 m a.s.l. The event must have been huge compared to the 1994 M 6.4 earthquake with the ensuing 0.4 m high tsunami in the same area, validating the intimidating tsunami risks in the South China Sea.
Ye Yuan, Huaiwei Yang, Fujiang Yu, Yi Gao, Benxia Li, and Chuang Xing
Nat. Hazards Earth Syst. Sci., 23, 3487–3507, https://doi.org/10.5194/nhess-23-3487-2023, https://doi.org/10.5194/nhess-23-3487-2023, 2023
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Rip currents are narrow jets of offshore-directed flow that originated in the surf zone, which can take swimmers of all ability levels into deeper water unawares. In this study, a 1 m fine-resolution wave-resolving model was configured to study rip current variability and the optimal swimmer escape strategies. Multiple factors contribute to the survival of swimmers. However, for weak-to-moderate rip and longshore currents, swimming onshore consistently seems to be the most successful strategy.
Benedikt Mester, Thomas Vogt, Seth Bryant, Christian Otto, Katja Frieler, and Jacob Schewe
Nat. Hazards Earth Syst. Sci., 23, 3467–3485, https://doi.org/10.5194/nhess-23-3467-2023, https://doi.org/10.5194/nhess-23-3467-2023, 2023
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In 2019, Cyclone Idai displaced more than 478 000 people in Mozambique. In our study, we use coastal flood modeling and satellite imagery to construct a counterfactual cyclone event without the effects of climate change. We show that 12 600–14 900 displacements can be attributed to sea level rise and the intensification of storm wind speeds due to global warming. Our impact attribution study is the first one on human displacement and one of very few for a low-income country.
Thomas P. Collings, Niall D. Quinn, Ivan D. Haigh, Joshua Green, Izzy Probyn, Hamish Wilkinson, Sanne Muis, William V. Sweet, and Paul D. Bates
EGUsphere, https://doi.org/10.5194/egusphere-2023-2267, https://doi.org/10.5194/egusphere-2023-2267, 2023
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Coastal areas are at risk of flooding from rising sea levels and extreme weather events. This study uses a new way to figure out how likely coastal flooding is around the world. The method uses data from observations and computer models to create a detailed map of where these floods might happen at the coast. The approach can predict flooding in areas where there is little or no data. The results can be used to help get ready for and prevent this type of flooding.
Mithun Deb, James Benedict, Ning Sun, Zhaoqing Yang, Robert Hetland, David Judi, and Taiping Wang
EGUsphere, https://doi.org/10.5194/egusphere-2023-2134, https://doi.org/10.5194/egusphere-2023-2134, 2023
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We coupled earth system, hydrology, and hydrodynamic models to generate plausible and physically consistent ensembles of hurricane events and their associated water levels from the open coast to tidal rivers of Delaware Bay and River. Our results show that the hurricane landfall locations and the estuarine wind can significantly amplify the extreme surge in a shallow and converging system, especially when the wind direction aligns with the surge propagation direction.
Kévin Dubois, Morten Andreas Dahl Larsen, Martin Drews, Erik Nilsson, and Anna Rutgersson
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2023-176, https://doi.org/10.5194/nhess-2023-176, 2023
Preprint under review for NHESS
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Both extreme river discharge and storm surges can interact at the coast and lead to flooding. However, it is difficult to predict flood levels during such compound events because they are rare and complex. Here, we focus on the quantification of uncertainties; and we investigate the sources of limitations while carrying out such analyses at Halmstad city (Sweden). Based on a sensitivity analysis, we emphasize that both the choice of data source and statistical methodology influence the results.
Olivier Cavalié, Frédéric Cappa, and Béatrice Pinel-Puysségur
Nat. Hazards Earth Syst. Sci., 23, 3235–3246, https://doi.org/10.5194/nhess-23-3235-2023, https://doi.org/10.5194/nhess-23-3235-2023, 2023
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Coastal areas are fragile ecosystems that face multiple hazards. In this study, we measured the downward motion of the Nice Côte d'Azur Airport (France) that was built on reclaimed area and found that it has subsided from 16 mm yr-1 in the 1990s to 8 mm yr-1 today. A continuous remote monitoring of the platform will provide key data for a detailed investigation of future subsidence maps, and this contribution will help to evaluate the potential failure of part of the airport platform.
Wagner L. L. Costa, Karin R. Bryan, and Giovanni Coco
Nat. Hazards Earth Syst. Sci., 23, 3125–3146, https://doi.org/10.5194/nhess-23-3125-2023, https://doi.org/10.5194/nhess-23-3125-2023, 2023
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For predicting flooding events at the coast, topo-bathymetric data are essential. However, elevation data can be unavailable. To tackle this issue, recent efforts have centred on the use of satellite-derived topography (SDT) and bathymetry (SDB). This work is aimed at evaluating their accuracy and use for flooding prediction in enclosed estuaries. Results show that the use of SDT and SDB in numerical modelling can produce similar predictions when compared to the surveyed elevation data.
Joshua Kiesel, Marvin Lorenz, Marcel König, Ulf Gräwe, and Athanasios T. Vafeidis
Nat. Hazards Earth Syst. Sci., 23, 2961–2985, https://doi.org/10.5194/nhess-23-2961-2023, https://doi.org/10.5194/nhess-23-2961-2023, 2023
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Among the Baltic Sea littoral states, Germany is anticipated to experience considerable damage as a result of increased coastal flooding due to sea-level rise (SLR). Here we apply a new modelling framework to simulate how flooding along the German Baltic Sea coast may change until 2100 if dikes are not upgraded. We find that the study region is highly exposed to flooding, and we emphasise the importance of current plans to update coastal protection in the future.
Zhang Haixia, Cheng Meng, and Fang Weihua
Nat. Hazards Earth Syst. Sci., 23, 2697–2717, https://doi.org/10.5194/nhess-23-2697-2023, https://doi.org/10.5194/nhess-23-2697-2023, 2023
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Simultaneous storm surge and waves can cause great damage due to cascading effects. Quantitative joint probability analysis is critical to determine their optimal protection design values. The joint probability of the surge and wave for the eastern coasts of Leizhou Peninsula and Hainan are estimated with a Gumbel copula based on 62 years of numerically simulated data, and the optimal design values under various joint return periods are derived using the non-linear programming method.
Clare Lewis, Tim Smyth, David Williams, Jess Neumann, and Hannah Cloke
Nat. Hazards Earth Syst. Sci., 23, 2531–2546, https://doi.org/10.5194/nhess-23-2531-2023, https://doi.org/10.5194/nhess-23-2531-2023, 2023
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Meteotsunami are globally occurring water waves initiated by atmospheric disturbances. Previous research has suggested that in the UK, meteotsunami are a rare phenomenon and tend to occur in the summer months. This article presents a revised and updated catalogue of 98 meteotsunami that occurred between 1750 and 2022. Results also demonstrate a larger percentage of winter events and a geographical pattern highlighting the
hotspotregions that experience these events.
Melissa Wood, Ivan D. Haigh, Quan Quan Le, Hung Nghia Nguyen, Hoang Ba Tran, Stephen E. Darby, Robert Marsh, Nikolaos Skliris, Joël J.-M. Hirschi, Robert J. Nicholls, and Nadia Bloemendaal
Nat. Hazards Earth Syst. Sci., 23, 2475–2504, https://doi.org/10.5194/nhess-23-2475-2023, https://doi.org/10.5194/nhess-23-2475-2023, 2023
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We used a novel database of simulated tropical cyclone tracks to explore whether typhoon-induced storm surges present a future flood risk to low-lying coastal communities around the South China Sea. We found that future climate change is likely to change tropical cyclone behaviour to an extent that this increases the severity and frequency of storm surges to Vietnam, southern China, and Thailand. Consequently, coastal flood defences need to be reviewed for resilience against this future hazard.
Sang-Guk Yum, Moon-Soo Song, and Manik Das Adhikari
Nat. Hazards Earth Syst. Sci., 23, 2449–2474, https://doi.org/10.5194/nhess-23-2449-2023, https://doi.org/10.5194/nhess-23-2449-2023, 2023
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This study performed analysis on typhoon-induced coastal morphodynamics for the Mokpo coast. Wetland vegetation was severely impacted by Typhoon Soulik, with 87.35 % of shoreline transects experiencing seaward migration. This result highlights the fact that sediment resuspension controls the land alteration process over the typhoon period. The land accretion process dominated during the pre- to post-typhoon periods.
Olle Räty, Marko Laine, Ulpu Leijala, Jani Särkkä, and Milla M. Johansson
Nat. Hazards Earth Syst. Sci., 23, 2403–2418, https://doi.org/10.5194/nhess-23-2403-2023, https://doi.org/10.5194/nhess-23-2403-2023, 2023
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We studied annual maximum sea levels in the Finnish coastal region. Our aim was to better quantify the uncertainty in them compared to previous studies. Using four statistical models, we found out that hierarchical models, which shared information on sea-level extremes across Finnish tide gauges, had lower uncertainty in their results in comparison with tide-gauge-specific fits. These models also suggested that the shape of the distribution for extreme sea levels is similar on the Finnish coast.
Christian Ferrarin, Florian Pantillon, Silvio Davolio, Marco Bajo, Mario Marcello Miglietta, Elenio Avolio, Diego S. Carrió, Ioannis Pytharoulis, Claudio Sanchez, Platon Patlakas, Juan Jesús González-Alemán, and Emmanouil Flaounas
Nat. Hazards Earth Syst. Sci., 23, 2273–2287, https://doi.org/10.5194/nhess-23-2273-2023, https://doi.org/10.5194/nhess-23-2273-2023, 2023
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The combined use of meteorological and ocean models enabled the analysis of extreme sea conditions driven by Medicane Ianos, which hit the western coast of Greece on 18 September 2020, flooding and damaging the coast. The large spread associated with the ensemble highlighted the high model uncertainty in simulating such an extreme weather event. The different simulations have been used for outlining hazard scenarios that represent a fundamental component of the coastal risk assessment.
Charline Dalinghaus, Giovanni Coco, and Pablo Higuera
Nat. Hazards Earth Syst. Sci., 23, 2157–2169, https://doi.org/10.5194/nhess-23-2157-2023, https://doi.org/10.5194/nhess-23-2157-2023, 2023
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Wave setup is a critical component of coastal flooding. Consequently, understanding and being able to predict wave setup is vital to protect coastal resources and the population living near the shore. Here, we applied machine learning to improve the accuracy of present predictors of wave setup. The results show that the new predictors outperform existing formulas demonstrating the capability of machine learning models to provide a physically sound description of wave setup.
Ina Teutsch, Markus Brühl, Ralf Weisse, and Sander Wahls
Nat. Hazards Earth Syst. Sci., 23, 2053–2073, https://doi.org/10.5194/nhess-23-2053-2023, https://doi.org/10.5194/nhess-23-2053-2023, 2023
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Rogue waves exceed twice the significant wave height. They occur more often than expected in the shallow waters off Norderney. When applying a nonlinear Fourier transform for the Korteweg–de Vries equation to wave data from Norderney, we found differences in the soliton spectra of time series with and without rogue waves. A strongly outstanding soliton in the spectrum indicated an enhanced probability for rogue waves. We could attribute spectral solitons to the measured rogue waves.
Philipp Heinrich, Stefan Hagemann, Ralf Weisse, Corinna Schrum, Ute Daewel, and Lidia Gaslikova
Nat. Hazards Earth Syst. Sci., 23, 1967–1985, https://doi.org/10.5194/nhess-23-1967-2023, https://doi.org/10.5194/nhess-23-1967-2023, 2023
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High seawater levels co-occurring with high river discharges have the potential to cause destructive flooding. For the past decades, the number of such compound events was larger than expected by pure chance for most of the west-facing coasts in Europe. Additionally rivers with smaller catchments showed higher numbers. In most cases, such events were associated with a large-scale weather pattern characterized by westerly winds and strong rainfall.
Alexander Böhme, Birgit Gerkensmeier, Benedikt Bratz, Clemens Krautwald, Olaf Müller, Nils Goseberg, and Gabriele Gönnert
Nat. Hazards Earth Syst. Sci., 23, 1947–1966, https://doi.org/10.5194/nhess-23-1947-2023, https://doi.org/10.5194/nhess-23-1947-2023, 2023
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External surges in the North Sea are caused by low-pressure cells travelling over the northeast Atlantic. They influence extreme water levels on the German coast and have to be considered in the design process of coastal defence structures. This study collects data about external surges from 1995–2020 and analyses their causes, behaviours and potential trends. External surges often occur less than 72 h apart, enabling a single storm surge to be influenced by more than one external surge.
Kenta Tozato, Shuji Moriguchi, Shinsuke Takase, Yu Otake, Michael R. Motley, Anawat Suppasri, and Kenjiro Terada
Nat. Hazards Earth Syst. Sci., 23, 1891–1909, https://doi.org/10.5194/nhess-23-1891-2023, https://doi.org/10.5194/nhess-23-1891-2023, 2023
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This study presents a framework that efficiently investigates the optimal placement of facilities probabilistically based on advanced numerical simulation. Surrogate models for the numerical simulation are constructed using a mode decomposition technique. Monte Carlo simulations using the surrogate models are performed to evaluate failure probabilities. Using the results of the Monte Carlo simulations and the genetic algorithm, optimal placements can be investigated probabilistically.
Job C. M. Dullaart, Sanne Muis, Hans de Moel, Philip J. Ward, Dirk Eilander, and Jeroen C. J. H. Aerts
Nat. Hazards Earth Syst. Sci., 23, 1847–1862, https://doi.org/10.5194/nhess-23-1847-2023, https://doi.org/10.5194/nhess-23-1847-2023, 2023
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Coastal flooding is driven by storm surges and high tides and can be devastating. To gain an understanding of the threat posed by coastal flooding and to identify areas that are especially at risk, now and in the future, it is crucial to accurately model coastal inundation and assess the coastal flood hazard. Here, we present a global dataset with hydrographs that represent the typical evolution of an extreme sea level. These can be used to model coastal inundation more accurately.
Elin Andrée, Jian Su, Morten Andreas Dahl Larsen, Martin Drews, Martin Stendel, and Kristine Skovgaard Madsen
Nat. Hazards Earth Syst. Sci., 23, 1817–1834, https://doi.org/10.5194/nhess-23-1817-2023, https://doi.org/10.5194/nhess-23-1817-2023, 2023
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When natural processes interact, they may compound each other. The combined effect can amplify extreme sea levels, such as when a storm occurs at a time when the water level is already higher than usual. We used numerical modelling of a record-breaking storm surge in 1872 to show that other prior sea-level conditions could have further worsened the outcome. Our research highlights the need to consider the physical context of extreme sea levels in measures to reduce coastal flood risk.
Ekaterina Didenkulova, Ira Didenkulova, and Igor Medvedev
Nat. Hazards Earth Syst. Sci., 23, 1653–1663, https://doi.org/10.5194/nhess-23-1653-2023, https://doi.org/10.5194/nhess-23-1653-2023, 2023
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The paper is dedicated to freak wave accidents which happened in the world ocean in 2005–2021 and that were described in mass media sources. The database accounts for 429 events, all of which resulted in ship or coastal and offshore structure damage and/or human losses. In agreement with each freak wave event, we put background wave and wind conditions extracted from the climate reanalysis ERA5. We analyse their statistics and discuss the favourable conditions for freak wave occurrence.
Havu Pellikka, Milla M. Johansson, Maaria Nordman, and Kimmo Ruosteenoja
Nat. Hazards Earth Syst. Sci., 23, 1613–1630, https://doi.org/10.5194/nhess-23-1613-2023, https://doi.org/10.5194/nhess-23-1613-2023, 2023
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We explore the rate of past and future sea level rise at the Finnish coast, northeastern Baltic Sea, in 1901–2100. For this analysis, we use tide gauge observations, modelling results, and a probabilistic method to combine information from several sea level rise projections. We provide projections of local mean sea level by 2100 as probability distributions. The results can be used in adaptation planning in various sectors with different risk tolerance, e.g. land use planning or nuclear safety.
Carlos Corela, Afonso Loureiro, José Luis Duarte, Luis Matias, Tiago Rebelo, and Tiago Bartolomeu
Nat. Hazards Earth Syst. Sci., 23, 1433–1451, https://doi.org/10.5194/nhess-23-1433-2023, https://doi.org/10.5194/nhess-23-1433-2023, 2023
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We show that ocean-bottom seismometers are controlled by bottom currents, but these are not always a function of the tidal forcing. Instead we suggest that the ocean bottom has a flow regime resulting from two possible contributions: the permanent low-frequency bottom current and the tidal current along the full tidal cycle, between neap and spring tides. In the short-period noise band the ocean current generates harmonic tremors that corrupt the dataset records.
Chen Chen, Charles Koll, Haizhong Wang, and Michael K. Lindell
Nat. Hazards Earth Syst. Sci., 23, 733–749, https://doi.org/10.5194/nhess-23-733-2023, https://doi.org/10.5194/nhess-23-733-2023, 2023
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This paper uses empirical-data-based simulation to analyze how to evacuate efficiently from disasters. We find that departure delay time and evacuation decision have significant impacts on evacuation results. Evacuation results are more sensitive to walking speed, departure delay time, evacuation participation, and destinations than to other variables. This model can help authorities to prioritize resources for hazard education, community disaster preparedness, and resilience plans.
Ariadna Martín, Angel Amores, Alejandro Orfila, Tim Toomey, and Marta Marcos
Nat. Hazards Earth Syst. Sci., 23, 587–600, https://doi.org/10.5194/nhess-23-587-2023, https://doi.org/10.5194/nhess-23-587-2023, 2023
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Tropical cyclones (TCs) are among the potentially most hazardous phenomena affecting the coasts of the Caribbean Sea. This work simulates the coastal hazards in terms of sea surface elevation and waves that originate through the passage of these events. A set of 1000 TCs have been simulated, obtained from a set of synthetic cyclones that are consistent with present-day climate. Given the large number of hurricanes used, robust values of extreme sea levels and waves are computed along the coasts.
An-Chi Cheng, Anawat Suppasri, Kwanchai Pakoksung, and Fumihiko Imamura
Nat. Hazards Earth Syst. Sci., 23, 447–479, https://doi.org/10.5194/nhess-23-447-2023, https://doi.org/10.5194/nhess-23-447-2023, 2023
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Consecutive earthquakes occurred offshore of southern Taiwan on 26 December 2006. This event revealed unusual tsunami generation and propagation, as well as unexpected consequences for the southern Taiwanese coast (i.e., amplified waves and prolonged durations). This study aims to elucidate the source characteristics of the 2006 tsunami and the important behaviors responsible for tsunami hazards in Taiwan such as wave trapping and shelf resonance.
Jean Roger, Bernard Pelletier, Aditya Gusman, William Power, Xiaoming Wang, David Burbidge, and Maxime Duphil
Nat. Hazards Earth Syst. Sci., 23, 393–414, https://doi.org/10.5194/nhess-23-393-2023, https://doi.org/10.5194/nhess-23-393-2023, 2023
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On 10 February 2021 a magnitude 7.7 earthquake occurring at the southernmost part of the Vanuatu subduction zone triggered a regional tsunami that was recorded on many coastal gauges and DART stations of the south-west Pacific region. Beginning with a review of the tectonic setup and its implication in terms of tsunami generation in the region, this study aims to show our ability to reproduce a small tsunami with different types of rupture models and to discuss a larger magnitude 8.2 scenario.
Kathrin Wahle, Emil V. Stanev, and Joanna Staneva
Nat. Hazards Earth Syst. Sci., 23, 415–428, https://doi.org/10.5194/nhess-23-415-2023, https://doi.org/10.5194/nhess-23-415-2023, 2023
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Knowledge of what causes maximum water levels is often key in coastal management. Processes, such as storm surge and atmospheric forcing, alter the predicted tide. Whilst most of these processes are modeled in present-day ocean forecasting, there is still a need for a better understanding of situations where modeled and observed water levels deviate from each other. Here, we will use machine learning to detect such anomalies within a network of sea-level observations in the North Sea.
Chuan Li, H. Tuba Özkan-Haller, Gabriel García Medina, Robert A. Holman, Peter Ruggiero, Treena M. Jensen, David B. Elson, and William R. Schneider
Nat. Hazards Earth Syst. Sci., 23, 107–126, https://doi.org/10.5194/nhess-23-107-2023, https://doi.org/10.5194/nhess-23-107-2023, 2023
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In this work, we examine a set of observed extreme, non-earthquake-related and non-landslide-related wave runup events. Runup events with similar characteristics have previously been attributed to trapped waves, atmospheric disturbances, and abrupt breaking of long waves. However, we find that none of these mechanisms were likely at work in the observations we examined. We show that instead, these runup events were more likely due to energetic growth of bound infragravity waves.
Cited articles
AVISO: FES2014 – Global tide model: FES2014 was produced by Noveltis, Legos and CLS and distributed by Aviso+, with support from Cnes, AVISO [data set], https://www.aviso.altimetry.fr/es/data/products/auxiliary-products/global-tide-fes.html (last access: 13 November 2020), 2014.
Basson, G., van Zyl, J., Bosman, E., Sawadago, O., and Vonkeman, J.:
Conduct a coastal vulnerability: Breede River Estuary Floodline Assessment, Technical Report,
DEA&DP, Western Cape, South Africa, 313 pp., 2017.
Bastidas, L. A., Knighton, J., and Kline, S. W.: Parameter sensitivity and uncertainty analysis for a storm surge and wave model, Nat. Hazards Earth Syst. Sci., 16, 2195–2210, https://doi.org/10.5194/nhess-16-2195-2016, 2016.
Bevacqua, E., Maraun, D., Vousdoukas, M. I., Voukouvalas, E., Vrac, M., Mentaschi, L., and Widmann, M.:
Higher probability of compound flooding from precipitation and storm surge in Europe under anthropogenic climate change,
Science Advances,
5, eaaw5531, https://doi.org/10.1126/sciadv.aaw5531, 2019.
Bilskie, M. V. and Hagen, S. C.:
Defining Flood Zone Transitions in Low-Gradient Coastal Regions,
Geophys. Res. Lett.,
45, 2761–2770, https://doi.org/10.1002/2018GL077524, 2018.
Bilskie, M. V., Zhao, H., Resio, D., Atkinson, J., Cobell, Z., and Hagen, S. C.: Enhancing Flood Hazard Assessments in Coastal Louisiana Through Coupled Hydrologic and Surge Processes, Front. Water, 3, 832, https://doi.org/10.3389/frwa.2021.609231, 2021.
Brown, S., Nicholls, R. J., Goodwin, P., Haigh, I. D., Lincke, D., Vafeidis, A. T., and Hinkel, J.:
Quantifying Land and People Exposed to Sea-Level Rise with No Mitigation and 1.5 ∘C and 2.0 ∘C Rise in Global Temperatures to Year 2300,
Earths Future,
6, 583–600, https://doi.org/10.1002/2017EF000738, 2018.
Cai, H., Savenije, H. H. G., Jiang, C., Zhao, L., and Yang, Q.: Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge, Hydrol. Earth Syst. Sci., 20, 1177–1195, https://doi.org/10.5194/hess-20-1177-2016, 2016.
Carrère, L., Lyard, F., Cancet, M., and Guillot, A.: FES 2014, a new tidal model on the global ocean with enhanced accuracy in shallow seas and in the Arctic region, EGU General Assembly, available at: https://ui.adsabs.harvard.edu/abs/2015EGUGA..17.5481C/abstract (last access: 24 January 2022), 2015.
Carter, R. A.: Report 21 of the Estuaries of the Cape, Part 2: Synopses of available information on individual systems series, CSIR (CSIR research report 420), http://researchspace.csir.co.za/dspace/handle/10204/3462 (last access: 24 January 2022), 1983.
Chen, W.-B. and Liu, W.-C.: Modeling Flood Inundation Induced by River Flow and Storm Surges over a River Basin, Water, 6, 3182–3199, https://doi.org/10.3390/w6103182, 2014.
Chow, V. T.:
Open-channel hydraulics,
Blackburn Press, Caldwell, NJ, 680 pp., 1959.
Church, J. A., Clark, P. U., Cazenave, A., Gregory, J. M., Jevrejeva, S., Levermann, A., Merrifield, M. A., Milne, G. A., Nerem, R. S., Nunn, P. D., Payne, A. J., Pfeffer, W. T., Stammer, D., and Unnikrishnan, A. S.:
Sea Level Change,
Cambridge University Press, Cambridge, UK, and New York, NY, USA, 2013.
Codiga, D. L.:
Unified tidal analysis and prediction using the UTide Matlab functions,
Graduate School of Oceanography, University of Rhode Island, https://doi.org/10.13140/RG.2.1.3761.2008, 2011.
Cooper, J. A. G.: Geomorphological variability among microtidal estuaries from the wave-dominated South African coast, Geomorphology, 40, 99–122, 2001.
Couasnon, A., Eilander, D., Muis, S., Veldkamp, T. I. E., Haigh, I. D., Wahl, T., Winsemius, H. C., and Ward, P. J.: Measuring compound flood potential from river discharge and storm surge extremes at the global scale, Nat. Hazards Earth Syst. Sci., 20, 489–504, https://doi.org/10.5194/nhess-20-489-2020, 2020.
DEA: 2013-14 National Land Cover – 72 classes, Department of Environmental Affairs, https://doi.org/10.15493/DEA.CARBON.10000028, 2015.
DEA&DP: Sea Level Rise and Flood Risk Assessment for a Select Disaster Prone Area Along the Western Cape Coast. Level Rise and Flood Risk Modelling: Phase B: Overberg District Municipality. Phase 2 Report: Overberg District Municipality Sea, Department of Environmental Affairs and Development Planning, https://www.westerncape.gov.za/eadp/files/atoms/files/Overberg DM SLR Phase 3 Risk Assessment Final (March 2012).pdf (last access: 24 January 2022), 2012.
DEFF:
National Coastal Climate Change Vulnerability Assessment: Vulnerability Indices – Technical Report,
Department of Environment, Forestry and Fisheries, Pretoria, South Africa, 2020.
Delpey, M. T., Ardhuin, F., Otheguy, P., and Jouon, A.:
Effects of waves on coastal water dispersion in a small estuarine bay,
J. Geophys. Res.-Oceans,
119, 70–86, https://doi.org/10.1002/2013JC009466, 2014.
Deltares: Delft3D-FLOW: Simulation of multidimensional hydrodynamic flows and transport phenomena, including sediments, User Manual, Deltares, available at: https://oss.deltares.nl/documents/183920/185723/Delft3D-FLOW_User_Manual.pdf (last access: 19 July 2021), 2014.
Dodet, G., Melet, A., Ardhuin, F., Bertin, X., Idier, D., and Almar, R.:
The Contribution of Wind-Generated Waves to Coastal Sea-Level Changes,
Surv. Geophys.,
40, 1563–1601, https://doi.org/10.1007/s10712-019-09557-5, 2019.
DWS: Station H14T007, Department of Water and Sanitation,
available at: http://www.dwa.gov.za/hydrology (last access: 11 September 2020), 2020a
DWS: Station H7H006, Department of Water and Sanitation, available at: http://www.dwa.gov.za/hydrology (last access: 11 September 2020),, 2020b.
Eilander, D., Couasnon, A., Ikeuchi, H., Muis, S., Yamazaki, D., Winsemius, H., and Ward, P. J.: The effect of surge on riverine flood hazard and impact in deltas globally, Environ. Res. Lett., 15, 104007, https://doi.org/10.1088/1748-9326/ab8ca6, 2020.
Fitchett, J. M., Grant, B., and Hoogendoorn, G.: Climate change threats to two low-lying South African coastal towns: Risks and perceptions, S. Afr. J. Sci, 112, 1–9, https://doi.org/10.17159/sajs.2016/20150262, 2016.
Garzon, J. and Ferreira, C.:
Storm Surge Modelling in Large Estuaries: Sensitivity Analyses to Parameters and Physical Processes in the Chesapeake Bay,
Journal of Marine Science and Engineering,
4, 45, https://doi.org/10.3390/jmse4030045, 2016.
Godin, G. and Martínez, A.:
Numerical experiments to investigate the effects of quadratic friction on the propagation of tides in a channel,
Cont. Shelf Res.,
14, 723–748, https://doi.org/10.1016/0278-4343(94)90070-1, 1994.
Guastella, L. A. and Rossouw, M.: Coastal vulnerability: What will be the impact of increasing frequency and intensity of coastal storms along the South African coast?, Reef Journal, 2, 129–139, 2012.
Hallegatte, S., Green, C., Nicholls, R. J., and Corfee-Morlot, J.:
Future flood losses in major coastal cities,
Nat. Clim. Change,
3, 802–806, https://doi.org/10.1038/nclimate1979, 2013.
Hanson, S., Nicholls, R., Ranger, N., Hallegatte, S., Corfee-Morlot, J., Herweijer, C., and Chateau, J.:
A global ranking of port cities with high exposure to climate extremes,
Climatic Change,
104, 89–111, https://doi.org/10.1007/s10584-010-9977-4, 2011.
Harrison, L. M., Coulthard, T. J., Robins P. E., and Lewis, M. J.:
Sensitivity of Estuaries to Compound Flooding, Estuar. Coast., 44, 387, https://doi.org/10.1007/s12237-021-00996-1, 2021.
Hendry, A., Haigh, I. D., Nicholls, R. J., Winter, H., Neal, R., Wahl, T., Joly-Laugel, A., and Darby, S. E.: Assessing the characteristics and drivers of compound flooding events around the UK coast, Hydrol. Earth Syst. Sci., 23, 3117–3139, https://doi.org/10.5194/hess-23-3117-2019, 2019.
Holloway, A., Fortune, G., Chasi, V., and Beckman, T.:
RADAR Western Cape 2010: Risk and development annual review,
PeriPeri Publications, Disaster Mitigation for Sustainable Livelihoods Programme, Rondebosch, xv, 104, 2010.
Hughes, P. and Brundrit, G. B.: Sea Level Rise and Coastal Planning: A Call for Stricter Control in River Mouths, J. Coastal Res., 11, 887–898, 1995.
IPCC:
Climate change 2014: Synthesis report, Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change,
Intergovernmental Panel on Climate Change, Geneva, Switzerland, 151 pp., 2014.
Jung, I., Park, J., Park, G., Lee, M., and Kim, S.: A grid-based rainfall-runoff model for flood simulation including paddy fields, Paddy Water Environ., 9, 275–290, 2011.
Kaiser, G., Scheele, L., Kortenhaus, A., Løvholt, F., Römer, H., and Leschka, S.: The influence of land cover roughness on the results of high resolution tsunami inundation modeling, Nat. Hazards Earth Syst. Sci., 11, 2521–2540, https://doi.org/10.5194/nhess-11-2521-2011, 2011.
Kirezci, E., Young, I. R., Ranasinghe, R., Muis, S., Nicholls, R. J., Lincke, D., and Hinkel, J.:
Projections of global-scale extreme sea levels and resulting episodic coastal flooding over the 21st Century,
Sci. Rep.-UK,
10, 11629, https://doi.org/10.1038/s41598-020-67736-6, 2020.
Klerk, W. J., Winsemius, H. C., van Verseveld, W. J., Bakker, A. M. R., and Diermanse, F. L. M.:
The co-incidence of storm surges and extreme discharges within the Rhine–Meuse Delta,
Environ. Res. Lett.,
10, 35005, https://doi.org/10.1088/1748-9326/10/3/035005, 2015.
Kumbier, K., Carvalho, R. C., Vafeidis, A. T., and Woodroffe, C. D.: Investigating compound flooding in an estuary using hydrodynamic modelling: a case study from the Shoalhaven River, Australia, Nat. Hazards Earth Syst. Sci., 18, 463–477, https://doi.org/10.5194/nhess-18-463-2018, 2018.
Lamberth, S. J., van Niekerk, L., and Hutchings, K.:
Comparison of, and the effects of altered freshwater inflow on, fish assemblages of two contrasting South African estuaries: The cool-temperate Olifants and the warm-temperate Breede,
Afr. J. Mar. Sci.,
30, 311–336, https://doi.org/10.2989/AJMS.2008.30.2.9.559, 2008.
Lee, S., Kang, T., Sun, D., and Park, J.-J.:
Enhancing an Analysis Method of Compound Flooding in Coastal Areas by Linking Flow Simulation Models of Coasts and Watershed,
Sustainability,
12, 6572, https://doi.org/10.3390/su12166572, 2020.
Leonard, M., Westra, S., Phatak, A., Lambert, M., van den Hurk, B., McInnes, K., Risbey, J., Schuster, S., Jakob, D., and Stafford-Smith, M.:
A compound event framework for understanding extreme impacts,
WIREs Clim. Change, 5, 113–128, https://doi.org/10.1002/wcc.252, 2014.
Lesser, G. R., Roelvink, J. A., van Kester, J. A. T. M., and Stelling, G. S.:
Development and validation of a three-dimensional morphological model,
Coast. Eng.,
51, 883–915, https://doi.org/10.1016/j.coastaleng.2004.07.014, 2004.
Lyddon, C., Brown, J. M., Leonardi, N., and Plater, A. J.:
Uncertainty in estuarine extreme water level predictions due to surge-tide interaction,
PloS one,
13, e0206200, https://doi.org/10.1371/journal.pone.0206200, 2018.
Marcos, M., Rohmer, J., Vousdoukas, M. I., Mentaschi, L., Le Cozannet, G., and Amores A.: Increased Extreme Coastal Water levels due to the Combined Action of Storm Surge and Wind Waves, Geophys. Res. Lett., 46, 4356–4364, https://doi.org/10.1029/2019GL082599, 2019.
Mather, A. A. and Stretch, D.:
A Perspective on Sea Level Rise and Coastal Storm Surge from Southern and Eastern Africa: A Case Study Near Durban, South Africa,
Water,
4, 237–259, https://doi.org/10.3390/w4010237, 2012.
Matte, P., Secretan, Y., and Morin, J.:
Hydrodynamic Modelling of the St. Lawrence Fluvial Estuary. II: Reproduction of Spatial and Temporal Patterns,
Journal of Waterway, Port, Coastal, and Ocean Engineering,
143, 4017011, https://doi.org/10.1061/(ASCE)WW.1943-5460.0000394, 2017.
Mazas, F. and Hamm, L.:
An event-based approach for extreme joint probabilities of waves and sea levels,
Coast. Eng.,
122, 44–59, https://doi.org/10.1016/j.coastaleng.2017.02.003, 2017.
Melet, A., Meyssignac, B., Almar, R., and Le Cozannet, G.:
Under-estimated wave contribution to coastal sea-level rise,
Nat. Clim. Change,
8, 234–239, https://doi.org/10.1038/s41558-018-0088-y, 2018.
Molekwa, S.:
Cut-off lows over South Africa and their contribution to the total rainfall of the Eastern Cape Province,
Master's thesis,
University of Pretoria, Pretoria, 2013.
Molinari, D., De Bruijn, K., Castillo, J., Aronica, G. T., and Bouwer, L. M.: Review Article: Validation of flood risk models: current practice and innovations, Nat. Hazards Earth Syst. Sci. Discuss. [preprint], https://doi.org/10.5194/nhess-2017-303, 2017.
Moore, R. D., Wolf, J., Souza, A. J., and Flint, S. S.:
Morphological evolution of the Dee Estuary, Eastern Irish Sea, UK: A tidal asymmetry approach,
Geomorphology,
103, 588–596, 2009.
Mourato, S., Fernandez, P., Pereira, L., and Moreira, M.: Improving a DSM Obtained by Unmanned Aerial Vehicles for Flood Modelling, IOP C. Ser. Earth Env., 95, 1–9, 2017.
Muis, S., Verlaan, M., Nicholls, R. J., Brown, S., Hinkel, J., Lincke, D., Vafeidis, A. T., Scussolini, P., Winsemius, H. C., and Ward, P. J.:
A comparison of two global datasets of extreme sea levels and resulting flood exposure,
Earths Future,
5, 379–392, https://doi.org/10.1002/2016EF000430, 2017.
Myhre, G., Alterskjær, K., Stjern, C. W., Hodnebrog, Ø., Marelle, L., Samset, B. H., Sillmann, J., Schaller, N., Fischer, E., Schulz, M., and Stohl, A.:
Frequency of extreme precipitation increases extensively with event rareness under global warming,
Sci. Rep.-UK,
9, 16063, https://doi.org/10.1038/s41598-019-52277-4, 2019.
Nerem, R. S., Beckley, B. D., Fasullo, J. T., Hamlington, B. D., Masters, D., and Mitchum, G. T.:
Climate-change-driven accelerated sea-level rise detected in the altimeter era,
P. Natl. Acad. Sci. USA,
115, 2022–2025, https://doi.org/10.1073/pnas.1717312115, 2018.
Olabarrieta, M., Warner, J. C., and Kumar, N.:
Wave-current interaction in Willapa Bay,
J. Geophys. Res.,
116, C11011, https://doi.org/10.1029/2011JC007387, 2011.
Olbert, A. I., Comer, J., Nash, S., and Hartnett, M.:
High-resolution multi-scale modelling of coastal flooding due to tides, storm surges and rivers inflows. A Cork City example,
Coast. Eng.,
121, 278–296, https://doi.org/10.1016/j.coastaleng.2016.12.006, 2017.
Orton, P. M., Conticello, F. R., Cioffi, F., Hall, T. M., Georgas, N., Lall, U., Blumberg, A. F., and MacManus, K.:
Flood hazard assessment from storm tides, rain and sea level rise for a tidal river estuary,
Nat. Hazards,
102, 729–757, https://doi.org/10.1007/s11069-018-3251-x, 2020.
Pyle, D. M. and Jacobs, T. L.:
The Port Alfred floods of 17–23 October 2012: A case of disaster (mis)management?,
Jàmbá: Journal of Disaster Risk Studies,
8, 1–8, https://doi.org/10.4102/jamba.v8i1.207, 2016.
Ray, R. D., Loomis, B. D., Luthcke, S. B., and Rachlin, K. E.:
Tests of ocean-tide models by analysis of satellite-to-satellite range measurements: An update,
Geophys. J. Int.,
217, 1174–1178, https://doi.org/10.1093/gji/ggz062, 2019.
Rueda, A., Camus, P., Tomás, A., Vitousek, S., and Méndez, F. J.:
A multivariate extreme wave and storm surge climate emulator based on weather patterns,
Ocean Model.,
104, 242–251, https://doi.org/10.1016/j.ocemod.2016.06.008, 2016.
Sassi, M. G. and Hoitink, A. J. F.:
River flow controls on tides and tide-mean water level profiles in a tidal freshwater river,
J. Geophys. Res.-Oceans,
118, 4139–4151, https://doi.org/10.1002/jgrc.20297, 2013.
Schumann, E. H.:
Sea level variability in South African estuaries,
S. Afr. J. Sci,
109, 1–7, https://doi.org/10.1590/sajs.2013/1332, 2013.
Seenath, A., Wilson, M., and Miller, K.:
Hydrodynamic versus GIS modelling for coastal flood vulnerability assessment: Which is better for guiding coastal management?,
Ocean Coast. Manage.,
120, 99–109, https://doi.org/10.1016/j.ocecoaman.2015.11.019, 2016.
Seneviratne, S. I., Nicholls, N., Easterling, D., Goodess, C. M., Kanae, S., Kossin, J., Luo, Y., Marengo, J., McInnes, K., and Rahimi, M.: Changes in climate extremes and their impacts on the natural physical environment, in: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change (IPCC), Cambridge University Press, Cambridge, UK, and New York, NY, USA, 109–230, 2012.
Shen, Y., Morsy, M. M., Huxley, C., Tahvildari, N., and Goodall, J. L.:
Flood risk assessment and increased resilience for coastal urban watersheds under the combined impact of storm tide and heavy rainfall,
J. Hydrol.,
579, 124159, https://doi.org/10.1016/j.jhydrol.2019.124159, 2019.
Skinner, C. J., Coulthard, T. J., Parsons, D. R., Ramirez, J. A., Mullen, L., and Manson, S.:
Simulating tidal and storm surge hydraulics with a simple 2D inertia based model, in the Humber Estuary, U.K,
Estuar. Coast. Shelf S.,
155, 126–136, https://doi.org/10.1016/j.ecss.2015.01.019, 2015.
SSI: Breede River Estuarine Management Plan, Western Cape, South Africa, 86 pp., https://www.westerncape.gov.za/eadp/files/atoms/files/Breede_EMP_Gazetted June 2016 (final master).pdf (last access: 24 January 2022), 2016.
Stammer, D., Ray, R. D., Andersen, O. B., Arbic, B. K., Bosch, W., Carrère, L., Cheng, Y., Chinn, D. S., Dushaw, B. D., Egbert, G. D., Erofeeva, S. Y., Fok, H. S., Green, J. A. M., Griffiths, S., King, M. A., Lapin, V., Lemoine, F. G., Luthcke, S. B., Lyard, F., Morison, J., Müller, M., Padman, L., Richman, J. G., Shriver, J. F., Shum, C. K., Taguchi, E., and Yi, Y.:
Accuracy assessment of global barotropic ocean tide models,
Rev. Geophys.,
52, 243–282, https://doi.org/10.1002/2014RG000450, 2014.
Taljaard, S.:
Breede River Basin Study: Intermediate Determination of Resource Directed Measures for the Breede River Estuary, Report,
Department of Water Affairs and Forestry, Stellenbosh, South Africa, 2003.
Tanaka, H., Tinh, N. X., and Nagabayashi, H.: Wave setup at different river entrance morphologies, in: Coastal Engineering 2008, 31st International Conference, 31 August–5 September 2008, Hamburg, Germany, https://doi.org/10.1142/9789814277426_0082, 2009.
Theron, A., Rossouw, M., Rautenbach, C. J., Saint Ange, U. von, Maherry, A., and August, M.: Determination of Inshore Wave Climate along the South African Coast – Phase 1 for Coastal Hazard and Vulnerability Assessment,
CSIR, Technical report, https://www.researchgate.net/publication/330244420_Determination_of_the_Inshore_wave_climate_along_the_South_African_coast_-_Phase_1_for_Coastal_Hazard_and_Vulnerability_Assessment/citations (last access: 24 January 2022), 2014.
Theron, A. K. and Rossouw, M.:
Analysis of potential coastal zone climate change impacts and possible response options in the southern African region, Coastal Climate Change Impacts Southern Africa, 1–10, https://ees.kuleuven.be/klimos/toolkit/documents/318_CPO-0029.pdf (last access: 24 January 2022), 2008.
Theron, A. K., Rossouw, M., Barwell, L., Maherry, A., Diedericks, G., and de Wet, P.: Quantification of risks to coastal areas and development: wave run-up and erosion, 17 pp., CSIR Internal Report, https://www.researchgate.net/publication/46063479_Quantification_of_risks_to_coastal_areas_and_development_wave_run-up_and_erosion/citations (last access: 24 January 2022), 2010.
van Niekerk, A.: Stellenbosch University Digital Elevation Model (SUDEM),
Centre for Geographical Analysis, Stellenbosh University [data set], https://doi.org/10.13140/RG.2.1.3015.5922, 2016.
van Niekerk, L., Adams, J. B., James, N. C., Lamberth, S. J., MacKay, C. F., Turpie, J. K., Rajkaran, A., Weerts, S. P., and Whitfield, A. K.:
An Estuary Ecosystem Classification that encompasses biogeography and a high diversity of types in support of protection and management,
Afr. J. Aquat. Sci.,
45, 199–216, https://doi.org/10.2989/16085914.2019.1685934, 2020.
van Vliet, M. T. H., Franssen, W. H. P., Yearsley, J. R., Ludwig, F., Haddeland, I., Lettenmaier, D. P., and Kabat, P.:
Global river discharge and water temperature under climate change,
Global Environ. Chang.,
23, 450–464, https://doi.org/10.1016/j.gloenvcha.2012.11.002, 2013.
Vitousek, S., Barnard, P. L., Fletcher, C. H., Frazer, N., Erikson, L., and Storlazzi, C. D.: Doubling of coastal flooding frequency within decades due to sea-level rise, Scient. Rep., 7, 1399, https://doi.org/10.1038/s41598-017-01362-7, 2017.
Vonkeman, J., Sawadago, O., Bosman, E., and Basson, G.: Hydrodynamic modelling of extreme flood levels in an estuary due to climate change, in: SEDHYD2019-Federal Interagency Sedimentation and Hydrologic Modeling, Nevada, USA, 2019.
Vousdoukas, M. I., Voukouvalas, E., Mentaschi, L., Dottori, F., Giardino, A., Bouziotas, D., Bianchi, A., Salamon, P., and Feyen, L.: Developments in large-scale coastal flood hazard mapping, Nat. Hazards Earth Syst. Sci., 16, 1841–1853, https://doi.org/10.5194/nhess-16-1841-2016, 2016.
Wahl, T., Jain, S., Bender, J., Meyers, S. D., and Luther, M. E.:
Increasing risk of compound flooding from storm surge and rainfall for major US cities,
Nat. Clim. Change,
5, 1093–1097, https://doi.org/10.1038/nclimate2736, 2015.
Wamsley, T., Cialone, M., Smith, J., Ebersole, B., and Grzegorzewski, A.:
Influence of Landscape Restoration and Degradation on Storm Surge and Waves in Southern Louisiana, Nat. Hazards, 51, 207–224, 2009.
Wang, Z. B., Vandenbruwaene, W., Taal, M., and Winterwerp, H.:
Amplification and deformation of tidal wave in the Upper Scheldt Estuary,
Ocean Dynam.,
69, 829–839, https://doi.org/10.1007/s10236-019-01281-3, 2019.
Ward, P. J., Jongman, B., Aerts, J. C. J. H., Bates, P. D., Botzen, W. J. W., Diaz Loaiza, A., Hallegatte, S., Kind, J. M., Kwadijk, J., Scussolini, P., and Winsemius, H. C.:
A global framework for future costs and benefits of river-flood protection in urban areas,
Nat. Clim. Change,
7, 642–646, https://doi.org/10.1038/nclimate3350, 2017.
Ward, P. J., Couasnon, A., Eilander, D., Haigh, I. D., Hendry, A., Muis, S., Veldkamp, T. I. E., Winsemius, H. C., and Wahl, T.:
Dependence between high sea-level and high river discharge increases flood hazard in global deltas and estuaries,
Environ. Res. Lett.,
13, 84012, https://doi.org/10.1088/1748-9326/aad400, 2018.
Whitfield, A. K., Bate, G. C., Adams, J. B., Cowley, P. D., froneman, P. W., Gama, P. T., Strydom, N. A., Taljaard, S., Theron, A. K., Turpie, J. K., van Niekerk, L., and Wooldridge, T. H.:
Areview of the ecology and management of temporarily open/closed estuaries in South Africa, with particular emphasis on river flow and mouth state as primary drivers of these systems,
Afr. J. Mar. Sci.,
34, 163–180, 2012.
Xu, J.-Y., Liu, S.-X., Li, J.-X., and Jia, W.: Experimental study of wave propagation characteristics on a simplified coral reef, J. Hydrodyn., 32, 385–397, https://doi.org/10.1007/s42241-019-0069-2, 2020.
Zaki, Z. Z. M., Peirson, W. L., and Cox, R.: 2-D Investigation of River Flow on Wave Setup in Estuaries, in: Australasian Coasts & Ports Conference 2015: 22nd Australasian Coastal and Ocean Engineering Conference and the 15th Australasian Port and Harbour Conference, Engineers Australia and IPENZ, Auckland, New Zealand, 578–581, https://doi.org/10.3316/informit.733025219247658, 2015.
Zscheischler, J., Westra, S., van den Hurk, B. J. J. M., Seneviratne, S. I., Ward, P. J., Pitman, A., AghaKouchak, A., Bresch, D. N., Leonard, M., Wahl, T., and Zhang, X.:
Future climate risk from compound events,
Nat. Clim. Change,
8, 469–477, https://doi.org/10.1038/s41558-018-0156-3, 2018.
Short summary
In coastal regions, flooding can occur from combined tides, storms, river discharge, and waves. Effects of waves are commonly neglected when assessing flooding, although these may strongly contribute to extreme water levels. We find that waves combined with tides and river discharge at Breede Estuary, South Africa, increased flood extent and depth and caused earlier flooding than when waves were neglected. This highlights the need to consider all major flood drivers in future flood assessments.
In coastal regions, flooding can occur from combined tides, storms, river discharge, and waves....
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