Spatial variability in the trends in extreme storm surges and weekly-scale high water levels in the eastern Baltic Sea

Abstract. Sustainable management of the coastal resources requires a better understanding of the processes that drive coastline change. The coastline is a highly dynamic sea-terrestrial interface. It is affected by forcing factors such as water levels, waves, winds, and the highest and most severe changes occur during storm surges. Extreme storms are drivers responsible for rapid and sometimes dramatic changes of the coastline. The consequences of the impacts from these events entail a broad range of social, economic and natural resource considerations from threats to humans, infrastructure and habitats. This study investigates the impact of a severe storm on coastline response on a sandy multi-barred beach at the Belgian coast. Airborne LiDAR surveys acquired pre- and post-storm covering an area larger than 1 km2 were analyzed and reproducible monitoring solutions adapted to assess beach morphological changes were applied. Results indicated that the coast retreated by a maximum of 14.7 m where the embryo dunes in front of the fixed dunes were vanished and the foredune undercut. Storm surge and wave attacks were probably the most energetic there. However, the response of the coastline proxies associated with the mean high water line (MHW) and dunetoe (DuneT) was spatially variable. Based on the extracted beach features, good correlations (r>0.73) were found between coastline, berm and inner intertidal bar morphology, while it was weak with the most seaward bars covered in the surveys. This highlights the role of the upper features on the beach to protect the coastline from storm erosion by reducing wave energy. The findings are of critical importance in improving our knowledge and forecasting of coastline response to storms, and also in its translation into management practices.

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Role of intertidal wetlands for tidal and storm tide attenuation along a confined estuary: a model study

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-3181-2015 ◽

2015 ◽

Vol 3 (5) ◽

pp. 3181-3224 ◽

Cited By ~ 5

Author(s):

S. Smolders ◽

Y. Plancke ◽

S. Ides ◽

P. Meire ◽

S. Temmerman

Keyword(s):

Surface Area ◽

Wave Attenuation ◽

Spring Tide ◽

Storm Surges ◽

High Water ◽

Water Levels ◽

Storm Tide ◽

Flood Risks ◽

Model Study

Abstract. Coastal lowlands and estuaries are subjected to increasing flood risks during storm surges due to global and regional changes. Tidal wetlands are increasingly valued as effective natural buffers for storm surges by dissipating wave energy and providing flood water storage. While previous studies focused on flood wave attenuation within and behind wetlands, this study focuses on the effects of estuarine wetland properties on the attenuation of a storm tide that propagates along the length of an estuary. Wetland properties including elevation, surface area, and location within the estuary were investigated using a numerical model of the Scheldt estuary (Belgium, SW Netherlands). For a spring tide lower wetland elevations result in more attenuation of high water levels along the estuary, while for a higher storm tide higher elevations provide more attenuation compared to lower wetland elevations. For spring and storm tide a arger wetland surface area results in a better attenuation along the estuary up to a threshold wetland size for which larger wetlands do not further contribute to more attenuation. Finally a wetland of the same size and elevation, but located more upstream in the estuary, can store a larger proportion of the local flood volume and therefore has a larger attenuating effect on upstream high water levels. With this paper we aim to contribute towards a better understanding and wider implementation of ecosystem-based adaptation to increasing estuarine flood risks associated with storms.

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An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

Ocean Science ◽

10.5194/os-5-369-2009 ◽

2009 ◽

Vol 5 (3) ◽

pp. 369-378 ◽

Cited By ~ 86

Author(s):

A. Sterl ◽

H. van den Brink ◽

H. de Vries ◽

R. Haarsma ◽

E. van Meijgaard

Keyword(s):

North Sea ◽

Climate Model ◽

Sea Water ◽

Global Climate ◽

Global Climate Model ◽

Storm Surges ◽

Water Levels ◽

The North ◽

Extreme Storm ◽

The North Sea

Abstract. The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

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FREQUENCIES AND PROBABILITIES OF EXTREME STORM SURGES

Coastal Engineering Proceedings ◽

10.9753/icce.v16.54 ◽

1978 ◽

Vol 1 (16) ◽

pp. 54

Author(s):

Alfred Bohrbuter

Keyword(s):

Storm Surges ◽

Weather Conditions ◽

Water Levels ◽

High Wind ◽

Shallow Sea ◽

The North ◽

Extreme Storm ◽

Mean Wind Speed ◽

The North Sea ◽

Set Up

The North Sea as a very shallow sea with high wind set-up effects is acting highly as extremely sensitive measuring equipment for climatic changes, especially for surge producing weather conditions. The flood disaster in the Netherlands 1953, in Germany 1962, the Adolph-Bermpohl-Orkan (1967), with mean wind speed of 37 ra/sec. over 5 hours, the strong continental storm with high damages in the forests from France till Poland in November 1972, a series of 6 heavy floods in November/ December 1973 and two extreme floods in January 1976 with the highest water levels ever registrated in the German bight are indications for some changes in meteorological conditions. In this paper some hypothetical models shall be introduced which are able to show how extreme storm surge frequencies and probabilities are changing with time.

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DETERMINATION OF COMBINED PROBABILITIES OF OCCURRENCE OF WATER LEVELS AND WAVE HEIGHTS FOR THE SAFETY OF DIKES AT THE BALTIC SEA

Coastal Engineering Proceedings ◽

10.9753/icce.v35.management.6 ◽

2017 ◽

pp. 6

Author(s):

Christian Kaehler ◽

Christian Schlamkow ◽

Fokke Saathoff

Keyword(s):

Baltic Sea ◽

Storm Surges ◽

Water Levels ◽

The Baltic Sea ◽

Copula Models ◽

Protective Function ◽

Safety Standards ◽

Wave Heights ◽

The Baltic

Large parts of the Baltic Sea coast in Germany are protected by dikes against storm surges and floods. The dikes are designed to resist storm surges and floods, also taking into consideration of climate changes and sea level rise. To ensure the protective function the safety standards of the dikes are validated in regular intervals. This paper presents an approach to determine combined probabilities of occurrence of water level and wave heights for three selected sections. The probabilities of occurrence for defined return periods have been calculated by comparing several Copula models from the Archimedean Copula family.

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STORM SURGE FORECASTING METHODS IN ENCLOSED SEAS

Coastal Engineering Proceedings ◽

10.9753/icce.v16.58 ◽

1978 ◽

Vol 1 (16) ◽

pp. 58

Author(s):

P.F. Hamblin

Keyword(s):

Water Level ◽

Storm Surge ◽

Storm Surges ◽

High Water ◽

Computational Effort ◽

Water Levels ◽

Large Lakes ◽

Forecasting Methods ◽

The Stability ◽

Storm Surge Forecasting

Storm surges in enclosed seas although generally not as large in amplitude as their oceanic counterparts are nonetheless of considerable importance when low lying shoreline profiles, shallow water depth, and favourable geographical orientation to storm winds occur together. High water may result in shoreline innundation and in enhanced shoreline erosion. Conversely low water levels are hazardous to navigation. The purpose of this paper is to discuss the problem of storm surge forecasting in enclosed basins with emphasis on automated operational procedures. In general, operational forecasting methods must be based on standard forecast parameters, require a minimum of computational effort in the preparation of the forecast, must be applicable to lakes of different geometry and to any point on the shore, and to be able to resolve water level changes on an hourly basis to 10 cm in the case of high water level excursions associated with large lakes and less than that for smaller lakes. Particular physical effects arising in lakes which make these constraints difficult to fulfill are the reflections of resurgences of water levels arising from lateral boundaries, the stability of the atmospheric boundary layer and the presence of such subsynoptic disturbances as squall lines and travelling pressure jumps.

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Storm Surge Assessment Methodology Based on Numerical Modelling

10.29007/hrlw ◽

2018 ◽

Author(s):

Lara Santos ◽

Mariana Gomes ◽

Luis Vieira ◽

José Pinho ◽

José Antunes Do Carmo

Keyword(s):

Numerical Modelling ◽

Storm Surge ◽

Storm Surges ◽

High Water ◽

Automatic Generation ◽

Water Levels ◽

Tropical Storms ◽

Assessment Methodology ◽

Coastal Zones ◽

Generation Procedure

Coastal zones face severe weaknesses and high-risk situations due to coastal threats like erosion and storms and due to an increasing intensive occupation. Tropical storms events can contribute to the occurrence of these situations, by causing storm surges with high water levels and, consequently, episodes of waves overtopping and coastal flooding. This work aims to describe a methodology to estimate the storm surge occurrences in the Portuguese coastal zone, recurring to historical tropical storms data that occurred in the vicinity of Portugal and to numerical modeling of its characteristics. Delft3D software together with DelfDashboard tools were applied for the numerical modelling. An automatic generation procedure of storms was implemented based on the few available historical storms data characteristics. Obtained results allows to characterize storm surges along the Portuguese coast, identifying the most vulnerable areas and, consequently contributing for its proper planning and management.

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Upriver sightings of beluga whales (Delphinapterus leucas) follow storm surges and high water in the Mackenzie Delta, Northwest Territories, Canada

Arctic Science ◽

10.1139/as-2020-0010 ◽

2020 ◽

pp. 1-11

Author(s):

Kevin C. Scharffenberg ◽

Shannon A. MacPhee ◽

Lisa L. Loseto

Keyword(s):

Monitoring Program ◽

River Estuary ◽

Storm Surges ◽

High Water ◽

Small Sample ◽

Water Levels ◽

River Delta ◽

Delphinapterus Leucas ◽

Beluga Whales ◽

Mackenzie River

Each summer, Eastern Beaufort Sea beluga whales (Delphinapterus leucas (Pallas, 1776)) form a large congregation in the Tarium Niryutait Marine Protected Area (TNMPA) in the Mackenzie River estuary, a behaviour thought to be linked to warm, freshwater conditions. In 2018, >50 belugas were observed upriver near Aklavik in the Mackenzie River Delta. Community members noted that this upriver occurrence of belugas was unusual and suggested that wind-driven high water levels in the Mackenzie River were a primary driver. We investigated this explanation by searching past communications and reports for documentation of beluga sightings upriver and identifying storm surges and water-level changes at six hydrometric stations in the Mackenzie River Delta. We found three previous occurrences of belugas upriver dating back to 2000, all of which followed prominent surges in river level attributable to coastal storms. Although acknowledging a small sample size, we suggest that upriver occurrences of beluga whales warrant further investigation through extension of the TNMPA beluga monitoring program. As climate-driven changes cause more frequent and intense Arctic storm surges, we expect storm events to increasingly overlap with the annual summer beluga congregation. This may cause upriver movements to become more common, and population-level implications are not known.

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EVALUATION OF DESIGN WATER LEVELS AT THE EMS-DOLLARD ESTUARY CONSIDERING THE EFFECT OF A STORM SURGE BARRIER

Coastal Engineering Proceedings ◽

10.9753/icce.v32.management.43 ◽

2011 ◽

Vol 1 (32) ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Gerald Herrling ◽

Heiko Knaack ◽

Ralf Kaiser ◽

Hanz Dieter Niemeyer

Keyword(s):

Boundary Conditions ◽

Water Level ◽

Storm Surge ◽

Safety Margin ◽

Storm Surges ◽

High Water ◽

Water Levels ◽

Meteorological Model ◽

Area Of Interest ◽

Wind Velocities

In the Ems-Dollard estuary at the southern North Sea coast a revaluation of design water levels along the German dykes has become necessary, since the safety margin for sea level rise was increased by 25 cm due to a decision of the Lower Saxon Ministry for Environment and Climate Protection. The upstream part of the estuary is protected against high storm surges by a storm surge barrier. The closure of the barrier effects downstream surge water levels due to partial reflection. Deterministic-mathematical modeling is applied to evaluate design water levels and design wave run-up. Three severe storm surge events have been hindcasted by a cascade of three hierarchical models from the Continental Shelf over the German Bight into the area of interest. The models are forced by non-stationary and spatially varying data of atmospheric pressure, wind velocities and directions available of meteorological model investigations. The verification of the storm surge model with water level observations yields good agreements. With respect to legal boundary conditions, the single-value-method is applied to determine the highest expected high water level at Emden. Starting from this target water level, the wind velocities in the meteorological boundary conditions are increased with the aim to increase the surge level at the coast and to match the predetermined design water level at Emden. The responding water levels in the Ems-Dollard estuary assign the new design water levels.

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Flood and drought risk assessment for agricultural areas (Tagus Estuary, Portugal)

10.5194/nhess-2020-422 ◽

2021 ◽

Author(s):

Paula Freire ◽

Marta Rodrigues ◽

André B. Fortunato ◽

Alberto Freitas

Keyword(s):

Risk Assessment ◽

Local Level ◽

Storm Surges ◽

High Water ◽

Water Levels ◽

Tagus Estuary ◽

Risk Level ◽

Drought Risk ◽

Local Conditions ◽

Agricultural Areas

Abstract. Estuaries are coastal systems particularly vulnerable to climate change effects and within these systems, agriculture is one of the most potentially affected sectors. This paper proposes a risk assessment approach for helping the decision-making process at a local level, addressing two risks that affect agricultural areas located in estuarine margins: the unavailability of fresh water for irrigation resulting from the upstream propagation of estuarine brackish water during droughts, and land inundation by high water levels associated with high tides and storm surges. For each risk, quantitative consequence descriptors are presented to support risk level determination and evaluation through a continuous consequence/probability diagram. The approach applicability is discussed through its application to the Lezíria Grande de Vila Franca de Xira, located in the Tagus Estuary (Portugal). Results indicate that the approach is appropriate to support risk owners in taking actions to mitigate the risk. The flexibility of the approach to be adapted to local conditions and updated through time, and the ease of its application by the risk owner can be pointed out as the main strengths.

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