scholarly journals Distribution of coastal high water level during extreme events around the UK and Irish coasts

2021 ◽  
Vol 21 (11) ◽  
pp. 3339-3351
Author(s):  
Julia Rulent ◽  
Lucy M. Bricheno ◽  
J. A. Mattias Green ◽  
Ivan D. Haigh ◽  
Huw Lewis
Keyword(s):  
Water Level ◽  
Extreme Events ◽  
High Tide ◽  
High Water ◽  
Relative Contribution ◽  
High Flood ◽  
Environmental Prediction ◽  
The Uk ◽  
Total Water Level ◽  
Tidal Stage

Abstract. The interaction between waves, surges, and astronomical tides can lead to high coastal total water level (TWL), which can in turn trigger coastal flooding. Here, a high-resolution (1.5 km) simulation from a UK-focused regional coupled environmental prediction system is used to investigate the extreme events of winter 2013/4 around the UK and Irish coasts. The aim is to analyse the spatial distribution of coastal TWL and its components during this period by assessing (1) the relative contribution of different TWL components around the coast; (2) how extreme waves, surges, and tide interacted and if they occurred simultaneously; and (3) if this has implications in defining the severity of coastal hazard conditions. The TWL components' coastal distribution in winter 2013/4 was not constant in space, impacting differently over different regions. High (>90th percentile) waves and high surges occurred simultaneously at any tidal stage, including high tide (7.7 % of cases), but more often over the flood tide. During periods of high flood risk, a hazard proxy, defined as the sum of the sea surface height and half the significant wave height, at least doubled from average over three-quarters of the coast. These results have important implications for the risk management sector.

scholarly journals Distribution of coastal high water level during extreme events around the UK and Irish coasts

2021 ◽  
Author(s):  
Julia Rulent ◽  
Lucy M. Bricheno ◽  
Mattias J. A. Green ◽  
Ivan D. Haigh ◽  
Huw Lewis
Keyword(s):  
Water Level ◽  
Extreme Events ◽  
High Tide ◽  
High Water ◽  
Relative Contribution ◽  
High Flood ◽  
Environmental Prediction ◽  
The Uk ◽  
Total Water Level ◽  
Tidal Stage

Abstract. The interaction between waves, surges and astronomical tides can lead to high coastal total water level (TWL), which can in turn lead to coastal flooding. Here, a high resolution (1.5 km) simulation from a UK-focused regional coupled environmental prediction system is used to investigate the extreme events of winter 2013/4 around the UK and Irish coasts. The aim is to analyse the spatial distribution of coastal TWL and its components during this period by assessing 1- the relative contribution of different TWL components around the coast, 2- how extreme waves, surges and tide interacted and if they occurred simultaneously 3- if this has implications in defining the severity of coastal hazard conditions. The TWL components’ coastal distribution in winter 2013/4 was not constant in space, impacting differently over different regions. High (> 90th percentile) waves and surges occurred simultaneously at any tidal stage, including high tide (7.7 % of cases), but more often over the flood tide. During periods of high flood risk a hazard proxy, defined as the sum of the sea surface height and half the significant wave height, at least doubled from average over ¾ of the coast. These results have important implications for the risk management sector.

Extreme waves and surges interaction with tides during storms in winter 2013/2014.

2021 ◽  
Author(s):  
Julia Rulent
Keyword(s):  
Tidal Cycle ◽  
Grid Point ◽  
High Tide ◽  
Water Levels ◽  
Extreme Waves ◽  
Near Shore ◽  
The Uk ◽  
The Waves ◽  
Tidal Stage

<p>The interaction between waves, surges and tides is one of the main drivers of coastal total water levels (TWL).  Understanding this interaction is crucial for studying high TWL formation near shore, and to do this it is important to not only evaluate how high the TWL is but also when and where it occurs.</p><p>In this study we use a high resolution (1.5 km) three-way coupled (waves-atmosphere-ocean) numerical model developed by the MetOffice (UKC4) to study coastal conditions at the UK coast during the extreme events of winter 2013, which was chosen as case study because of the amount of flooding that occurred in relation to storms and surges during this period.</p><p>For each coastal grid point the ten strongest storms of that winter, ranked by the significant wave height (Hs) magnitude, were selected. During these storm periods, the number of hours in which Hs and surges exceeded the 90<sup>th</sup> percentile of winter 2013 were evaluated considering what tidal stage they occurred on. The same was done for instances where high Hs and surges occurred simultaneously. The aim is to understand if specific areas were predominantly affected by one of the TWL components and how Hs and surges interacted with the tide. What was the spatial distribution of the waves, surges, and tides during winter 2013? Did extreme Hs and Surges occur more often over specific stages of the tidal cycle? Did they occur simultaneously? </p><p>In this study we show that during the winter 2013, Hs and surges above the 90<sup>th</sup> percentile value did occur simultaneously at all stages of the tidal cycle. They more often occurred together over the rising tide with in average 8.7% and 8.6% of instances found two and three hours before high tide. In 7.7% of cases high wave and surges also concurred at high tide.</p>

Uncertainty in coastal flooding: modelling and visualisation

2020 ◽  
Author(s):  
John Maskell
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Return Period ◽  
Flood Risk ◽  
High Water ◽  
Coastal Flooding ◽  
Water Levels ◽  
Tidal Range ◽  
The Uk ◽  
Flood Maps

<p>Two case studies are considered in the UK, where uncertainty and drivers of coastal flood risk are explored through modelling and visualisations. Visualising the impact of uncertainty is a useful way of explaining the potential range of predicted or simulated flood risk to both expert and non-expert stakeholders.</p><p>Significant flooding occurred in December 2013 and January 2017 at Hornsea on the UK East Coast, where storm surge levels and waves overtopped the town’s coastal defences. Uncertainty in the potential coastal flooding is visualised at Hornsea due to the range of uncertainty in the 100-year return period water level and in the calculated overtopping due to 3 m waves at the defences. The range of uncertainty in the simulated flooding is visualised through flood maps, where various combinations of the uncertainties decrease or increase the simulated inundated area by 58% and 82% respectively.</p><p>Located at the mouth of the Mersey Estuary and facing the Irish Sea, New Brighton is affected by a large tidal range with potential storm surge and large waves. Uncertainty in the coastal flooding at the 100-year return period due to the combination of water levels and waves is explored through Monte-Carlo analysis and hydrodynamic modelling. Visualisation through flood maps shows that the inundation extent at New Brighton varies significantly for combined wave and surge events with a joint probability of 100 years, where the total flooded area ranges from 0 m<sup>2</sup> to 10,300 m<sup>2</sup>. Waves are an important flood mechanism at New Brighton but are dependent on high water levels to impact the coastal defences and reduce the effective freeboard. The combination of waves and high-water levels at this return level not only determine the magnitude of the flood extent but also the spatial characteristics of the risk, whereby flooding of residential properties is dominated by overflow from high water levels, and commercial and leisure properties are affected by large waves that occur when the water level is relatively high at the defences.</p>

scholarly journals Tidal Type Determination on Manokwari Shipping Chanel by Using Admiralty Method

2018 ◽  
pp. 57
Author(s):  
Suhaemi Suhaemi ◽  
Syafrudin Raharjo ◽  
Marhan Marhan
Keyword(s):  
Water Level ◽  
Full Moon ◽  
High Tide ◽  
High Water ◽  
Tidal Range ◽  
Tidal Amplitude ◽  
Gravitational Forces ◽  
Sea Transportation ◽  
Gravitational Pull ◽  
Tidal Waters

Tidal waters are very important for port interests, sea transportation, fisheries industry, coastal engineering and coastal area mitigation. Tidal height formed is a superposition of tidal amplitude due to the gravitational pull of the sun, moon and earth. The Tidal components are K1, O1, P1, S2, M2, K2, M4, MS4. This study aims to determine the components and types of tides in the shipping channel of Manokwari-West Papua using the admiralty method. Formzahl 0.732 number means the type of tidal that is formed is mixed tide prevailing semidiurnal, two high and low tide, two high and one low tide or two times low tide one high tide in a day. Mean Sea Level (MSL) was caused by water conditions, coastlines and bathymetry, the gravitational forces of the moon and sun. The MSL was obtained 98 cm. large tidal range occurs during full moon conditions and low tides occur during perbani (1.62-2.44 m). The amplitude Mean High Water Level level reaches 279 cm and Mean Low Water Level reaches -83 cm.

scholarly journals Inundation due to the tide in the context of sea level rise and the role of Can-Gio forest in the reduction of inundation

2018 ◽  
Vol 20 (K7) ◽  
pp. 76-85
Author(s):  
Hoa Thi Le ◽  
Hoa Tang My Son ◽  
Hong Thi My Tran ◽  
Giang Song Le
Keyword(s):  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
High Tide ◽  
High Water ◽  
High Water Level ◽  
Maximum Water Level ◽  
Level Increase ◽  
The Future ◽  
Calculation Results

Lower basin of Sai Gon – Dong Nai river is lowland. It’s inundated at high tide. Using mathematical model method with the integrated 1D2D model, the inundation hazard due to the high tide in this region has been evaluated through the inundated area. The calculation results also showed that in the case when the damping ability of Can Gio forest is disabled high water level at Nha Be and Phu An can be increased about 2 – 3 cm and the effect will be stronger in the future following the sea level rise. In the case the Can Gio forest is diked to create a reservoir with reasonable in- and outflow directions, the high water level at Nha Be and Phu An can be decreased about 10 - 11 cm and the effect will be stronger in the future following the sea level rise. This water level decrease effect almost compensates the water level increase due to the sea level rise and keeps the maximum water level at Phu An not exceed actual one until 2050 regardless the sea level rise.

Estimating the probabilities of combined events

1994 ◽  
Vol 21 (6) ◽  
pp. 1088-1091
Author(s):  
S. O. Denis Russell ◽  
Ken-Beck Lee
Keyword(s):  
Water Level ◽  
Ad Hoc ◽  
High Tide ◽  
High Water ◽  
High Flow ◽  
Water Levels ◽  
Probability Estimation ◽  
Design Engineers ◽  
Flood Probability ◽  
Design Water Level

In coastal areas, high water levels often result from a combination of events such as high tide and high flow. For such areas, design engineers often have to estimate the water level that would be exceeded with a specified probability. Several methods, including the traditional ad-hoc way, of making such estimates are compared for simple situations, where it is possible to obtain exact answers by numerical integration. Key words: floods, flood probability, combined probability, probability estimation, design water level.

scholarly journals Assessment of coastal flooding and associated hydrodynamic processes on the south-eastern coast of Mexico, during Central American cold surge events

2018 ◽  
Vol 18 (6) ◽  
pp. 1681-1701 ◽  
Author(s):  
Wilmer Rey ◽  
Paulo Salles ◽  
E. Tonatiuh Mendoza ◽  
Alec Torres-Freyermuth ◽  
Christian M. Appendini
Keyword(s):  
Water Level ◽  
Tide Gauge ◽  
High Tide ◽  
Coastal Flooding ◽  
Numerical Results ◽  
Eastern Coast ◽  
Tide Gauge Records ◽  
Relative Contribution ◽  
Hydrodynamic Processes ◽  
Set Up

Abstract. Coastal flooding in the northern Yucatán Peninsula is mainly associated with storm surge events triggered by high-pressure cold front systems. This study evaluates the hydrodynamic processes of the Chelem lagoon, Mexico and the flooding threat from cold fronts for the neighbouring town of Progreso. A 30-year water-level hindcast (excluding wave set-up) was performed because of the lack of long-term tide gauge records. In order to assess the relative contribution from wave set-up and residual and astronomical tides to total flooding, the two worst storm scenarios in terms of maximum residual tide (Event A) and maximum water level (Event B) were simulated. Numerical results suggest that during Event A the wave set-up contribution reaches 0.35 at the coast and 0.17 m inside the lagoon, and these values are smaller for Event B (0.30 and 0.14 m, respectively). Results of the effect of the tidal phase on wave set-up and residual sea level show that (i) the wave set-up contribution increases during ebb tide and decreases during flood tide at the Chelem inlet, (ii) the residual tide is larger (smaller) near low (high) or receding (rising) tide, and (iii) maximum flooding occurs when the storm peak coincides with rising or high tide. The numerical results confirm the important role of wave set-up on the assessment of coastal flooding in micro-tidal coastal environments.

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling
Keyword(s):  
Water Level ◽  
Bronze Age ◽  
Environmental Changes ◽  
High Water ◽  
Alluvial Fan ◽  
Water Levels ◽  
Lake Area ◽  
Dune Field ◽  
The North ◽  
Sand Drift

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

scholarly journals Radiational tides: their double-counting in storm surge forecasts and contribution to the Highest Astronomical Tide

Ocean Science ◽  
2018 ◽  
Vol 14 (5) ◽  
pp. 1057-1068 ◽  
Author(s):  
Joanne Williams ◽  
Maialen Irazoqui Apecechea ◽  
Andrew Saulter ◽  
Kevin J. Horsburgh
Keyword(s):  
Tide Gauge ◽  
Storm Surges ◽  
Double Counting ◽  
Atmospheric Conditions ◽  
Sea Level Changes ◽  
Astronomical Tide ◽  
Operational Forecasts ◽  
The Difference ◽  
The Uk ◽  
Total Water Level

Abstract. Tide predictions based on tide-gauge observations are not just the astronomical tides; they also contain radiational tides – periodic sea-level changes due to atmospheric conditions and solar forcing. This poses a problem of double-counting for operational forecasts of total water level during storm surges. In some surge forecasting, a regional model is run in two modes: tide only, with astronomic forcing alone; and tide and surge, forced additionally by surface winds and pressure. The surge residual is defined to be the difference between these configurations and is added to the local harmonic predictions from gauges. Here we use the Global Tide and Surge Model (GTSM) based on Delft-FM to investigate this in the UK and elsewhere, quantifying the weather-related tides that may be double-counted in operational forecasts. We show that the global S2 atmospheric tide is captured by the tide-and-surge model and observe changes in other major constituents, including M2. The Lowest and Highest Astronomical Tide levels, used in navigation datums and design heights, are derived from tide predictions based on observations. We use our findings on radiational tides to quantify the extent to which these levels may contain weather-related components.

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