Generation of Multivariate Wave Conditions as Input for a Probabilistic Level III Breakwater Design

For an offshore LNG project situated in the estuary of the Rio de la Plata nearby Montevideo, Uruguay, it was required to verify the deterministic design of the protective rubble mound breakwater and the jetty infrastructure with a level three probabilistic design. Therefore, in first instance extreme site conditions were required both in front of and behind the breakwater. To obtain these conditions, the first step is to extrapolate the offshore variables in order to translate them to the breakwater location. All the possible combinations of extreme wind, water level and waves are quantified with a probability of occurrence. A combination of univariate extreme value distributions, copula’s and regression is used to describe the multivariate statistical behaviour of the offshore variables. The main variable is the wind velocity, as in the area of concern extreme wave conditions are wind driven. The secondary variable is water level. Wind velocity and water levels are only correlated for some wind directions. For these directions, wind velocity and water level extreme value distributions are linked through a multivariate Gumbel Copula. The wave height at the model boundaries was taken into account by a regression function with the extreme wind velocity at the offshore location and the wave period by a regression function with the wave height. This way 1515 synthetic events were selected and simulated with the spectral wave model SWAN, each of which a frequency of occurrence is calculated for. However, due to refraction and diffraction effects of the approach channel (in the area of concern water depths are limited to about 7 m and the navigation channel has a depth of about 14 m), the port basin and the breakwater itself, the spectral wave model SWAN is not sufficient to accurately calculate the local wave conditions in the entire area of interest. Therefore a non-linear Boussinesq wave model (i.e. Mike 21 BW) was set up in addition, using input from the spectral model at the boundary and including the navigation channel of more than 12 km long. Combining both models, significant wave heights are obtained on both the seaward side and the leeside of the breakwater with corresponding frequencies of occurrence. This approach allows the determination of conditional return periods and generates the site conditions required for a probabilistic level three design of the breakwater and the jetty infrastructure taking for example the joint probabilities between waves and water levels fully into account as needed for overtopping or failure calculations.

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A PARAMETRIC HURRICANE WAVE PREDICTION MODEL

Coastal Engineering Proceedings ◽

10.9753/icce.v21.82 ◽

1988 ◽

Vol 1 (21) ◽

pp. 82

Author(s):

Ian R. Young

Keyword(s):

Spatial Distribution ◽

Radiative Transfer Equation ◽

Synthetic Data ◽

Wave Model ◽

Limited Growth ◽

Forward Movement ◽

Spectral Wave Model ◽

Wave Conditions ◽

Two Parameters ◽

The Waves

A spectral wave model based on a numerical solution of the Radiative Transfer Equation is used to create a synthetic data base on wave conditions within hurricanes. The results indicate that both the velocity of forward movement and maximum wind velocity within the storm play an important role in determining both the magnitude of the waves generated and also the spatial distribution of these waves. An equivalent fetch for hurricane wave generation which is a function of these two parameters is proposed. This concept, together with the standard JONSWAP fetch limited growth relationships, provide a simple means for estimating wave conditions within hurricanes.

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Wave model verification based on measurements in the Wadden Sea

10.5194/os-2016-28 ◽

2016 ◽

Author(s):

Cordula Berkenbrink ◽

Luise Hentze ◽

Andreas Wurpts

Keyword(s):

Water Level ◽

Wadden Sea ◽

Wave Attenuation ◽

Calculated Data ◽

Barrier Islands ◽

Wave Model ◽

Water Levels ◽

Model Verification ◽

Coastal Protection ◽

Lower Saxony

Abstract. The design height of coastal protection structures in Lower Saxony / Germany is determined by the design water level and the corresponding wave run up. For the calculation of these parameters several mathematical models are used which need to be verified for the conditions at the East Frisian Wadden Sea area. For this issue a wave measuring programme is operationally run, which includes various measurement locations and devices around the islands Norderney and Juist. The measurements are continuously extended and adapted in order to improve models and measurements. This paper shows a comparison between measured and calculated data for the storm surge of the 10.–11.01.2015 incorporating to new wave and water level gauges operated within COSYNA as well as a second research project dealing with wave attenuation behind barrier islands. Water levels within the investigation area were calculated by hydrodynamic models driven with a wind field originating from weather forecast and compared to water level measurements. The corresponding wave energy field was calculated by means of a third generation wave model and results compared to measurements of several devices located around the barrier Islands. The aim of the study shown here is to give a brief overview of possible error sources for model-data as well as data-data comparisons.

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INVESTIGATION OF WAVE INDUCED STORM SURGE WITHIN A LARGE COASTAL EMBAYMENT - MORETON BAY (AUSTRALIA)

Coastal Engineering Proceedings ◽

10.9753/icce.v32.currents.22 ◽

2011 ◽

Vol 1 (32) ◽

pp. 22 ◽

Cited By ~ 1

Author(s):

Philip Treloar ◽

David Taylor ◽

Paul Prenzler

Keyword(s):

Water Level ◽

Tropical Cyclones ◽

Storm Surge ◽

Wave Model ◽

Water Levels ◽

Residual Water ◽

Storm Tide ◽

Moreton Bay ◽

Coastal Embayment ◽

Set Up

Moreton Bay is a large coastal embayment on the south-east Queensland coast which is surrounded by the urbanised areas of greater Brisbane on its western and southern shorelines. It is protected from the open coast by a number of islands, including South Stradbroke, North Stradbroke and Moreton Islands. Tropical cyclones occasionally track far enough south to cause significant damage to south-east Queensland due to flooding, winds, waves and elevated ocean water levels. Distant tropical cyclones which may be several hundred kilometres north of Moreton Bay have been known to cause storm surge, high waves and erosion inside Moreton Bay. These events generally do not generate gale force winds within Moreton Bay, but can generate large ocean swell waves. It has been identified that the wave conditions generated from distant cyclones can cause a variation in water levels inside Moreton Bay. A detailed study was undertaken to investigate the regional wave set-up process which affects Moreton Bay. The simulation of the residual water levels within Moreton Bay using a coupled hydrodynamic and wave model system developed for this study is considerably more accurate than applying a hydrodynamic model alone and explains water level anomalies that have a tidal frequency. The paper discusses the physical process of regional wave set-up inside a large embayment, analysis of observed residual water level and also the modelling study undertaken to quantify the influence of waves on storm tide levels inside Moreton Bay. The storm tide hazard study for the Moreton Bay Councils included the effects of regional wave set-up in the specification of design water levels.

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Numerical simulation of wave conditions in nearshore island area for sea-crossing bridge using spectral wave model

Advances in Structural Engineering ◽

10.1177/1369433217732493 ◽

2017 ◽

Vol 21 (5) ◽

pp. 756-768 ◽

Cited By ~ 7

Author(s):

Zilong Ti ◽

Kai Wei ◽

Shunquan Qin ◽

Yongle Li ◽

Dapeng Mei

Keyword(s):

Numerical Simulation ◽

Spatial Pattern ◽

Wave Model ◽

High Energy ◽

Engineering Practice ◽

Breaking Wave ◽

Bridge Site ◽

Island Area ◽

Spectral Wave Model ◽

Wave Conditions

The assessment of wave conditions is a primary task for the design, construction, and structural analysis of sea-crossing bridge. This article presents a numerical simulation and a field measurement to study the wave conditions in the nearshore island area for sea-crossing bridges. Pingtan Strait sea-crossing bridge site was selected as an example of nearshore island area. A 3-day high-energy wave event was measured and simulated using spectral wave model. The parameters of the numerical model were calibrated through the comparison with the field measured wave data. The spatial pattern of wave conditions along the bridge and the wave-breaking zone were analyzed based on the calibrated model. The analytical procedures suggested in the Chinese Code for nearshore wave prediction were finally testified through the comparison with numerical results. The research showed that (1) spectral wave model predicts the wave conditions in bridge site reasonably; (2) seabed terrain and islands significantly influence wave conditions, wave spatial pattern, and breaking wave zones; and (3) analytical wave simulation procedure recommended in the Code is not suitable to island area for sea-crossing bridge. This research allows a better understanding of wave conditions for sea-crossing bridge site and could provide useful reference for engineering practice.

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Hydrodynamic Climate of Port Phillip Bay

Journal of Marine Science and Engineering ◽

10.3390/jmse9080898 ◽

2021 ◽

Vol 9 (8) ◽

pp. 898

Author(s):

Huy Quang Tran ◽

David Provis ◽

Alexander V. Babanin

Keyword(s):

Coupled System ◽

Wave Model ◽

Water Levels ◽

Wave Direction ◽

Sea Levels ◽

Spectral Wave Model ◽

Coupling System ◽

Waves And Currents ◽

Wind Driven Currents ◽

Wind Patterns

This study is dedicated to the hydrodynamic climate of Port Phillip Bay (PPB)—a largest coastal lagoon system in Victoria, Australia. Novelty of the present study includes long-term hydrodynamic hindcast simulations integrated with a spectral wave model. Specifically, a coupled unstructured grid wave–current modelling system (SCHISM + WWM) was built upon a high resolution and advanced wave physics (ST6). This coupling system was thoroughly calibrated and validated against field observations prior to applying for 27-year hindcast and case scenarios. Data from these simulations were then used to investigate the hydrodynamic climate of PPB focusing on three main aspects: water levels, waves and currents. For sea levels, this study shows that tidal and extreme sea levels (storm tides) across a large part of PPB have a similar magnitude. The highest storm tide level is found along eastern coasts of the bay in line with the wind pattern. In the vicinity of the entrance, the extreme sea level slightly reduced, in line with wave decay due to coupling effects. This extreme level is lower than results reported by previous studies, which were not built on a wave–current coupled system. For the wave field, the mean wave direction inside PPB is strongly affected by seasonality, in line with wind patterns. The 100-year return significant wave height is above 2 m along the eastern coasts. At PPH, waves get refracted after passing the narrow entrance. For currents, this study shows that both mean variations and high percentile currents are not affected by seasonality. This highlights the fact that tidal currents dominate flow movements in PPB. However, in extreme conditions, the circulation in PPB is also driven by wind patterns, forming two gyre systems. Based on case scenarios simulations, the strongest magnitude of wind-driven currents is above 0.5 m/s and found in the confined shallow region in the southern portion of PPB.

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Combining probability distributions of sea level variations and wave run-up to evaluate coastal flooding risks

Natural Hazards and Earth System Science ◽

10.5194/nhess-18-2785-2018 ◽

2018 ◽

Vol 18 (10) ◽

pp. 2785-2799 ◽

Cited By ~ 2

Author(s):

Ulpu Leijala ◽

Jan-Victor Björkqvist ◽

Milla M. Johansson ◽

Havu Pellikka ◽

Lauri Laakso ◽

...

Keyword(s):

Water Level ◽

Sea Level ◽

Probability Distributions ◽

Water Levels ◽

Total Water ◽

Mean Sea Level ◽

Sea Level Variations ◽

Wave Conditions ◽

Run Up ◽

Total Water Level

Abstract. Tools for estimating probabilities of flooding hazards caused by the simultaneous effect of sea level and waves are needed for the secure planning of densely populated coastal areas that are strongly vulnerable to climate change. In this paper we present a method for combining location-specific probability distributions of three different components: (1) long-term mean sea level change, (2) short-term sea level variations and (3) wind-generated waves. We apply the method at two locations in the Helsinki archipelago to obtain total water level estimates representing the joint effect of the still water level and the wave run-up for the present, 2050 and 2100. The variability of the wave conditions between the study sites leads to a difference in the safe building levels of up to 1 m. The rising mean sea level in the Gulf of Finland and the uncertainty related to the associated scenarios contribute notably to the total water levels for the year 2100. A test with theoretical wave run-up distributions illustrates the effect of the relative magnitude of the sea level variations and wave conditions on the total water level. We also discuss our method's applicability to other coastal regions.

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Characteristics and dynamics of crescentic bar events at an open, Mediterranean beach

10.5194/egusphere-egu2020-18730 ◽

2020 ◽

Author(s):

Rinse de Swart ◽

Francesca Ribas ◽

Daniel Calvete ◽

Gonzalo Simarro ◽

Jorge Guillén

Keyword(s):

Visual Analysis ◽

Wave Model ◽

Wave Direction ◽

Geophysical Research ◽

Spectral Wave Model ◽

First Results ◽

Strong Relation ◽

Wave Conditions ◽

Using Data ◽

Bar Formation

Crescentic sand bars have attracted significant attention from coastal scientists during the last decades, which has lead to comparatively good understanding of their formation mechanism, as well as their characteristics and dynamics (e.g. Van Enckevort et al., 2004; Price and Ruessink, 2011). However, the effect of wave obliquity on crescentic bar formation is not yet clear, and processes like coupling of crescentic bars with megacusps deserve further attention. Furthermore, the mechanisms leading to crescentic bar straightening are not well understood. Previously, this was mainly linked to high-energetic wave conditions, but more recent studies (e.g. Price and Ruessink, 2011; Garnier et al., 2013) indicate that this is not always the case. Instead, those studies have found that bar straightening predominantly occurs when the waves are obliquely incident. Finally, there are not many studies of crescentic bars in fetch-limited environments with insignificant tides (such as Mediterranean beaches). Therefore, the objective of the present work is to increase our knowledge on the dynamics of crescentic bars (including bar straightening) using data from an open, Mediterranean beach (Castelldefels beach, 20 km southwest of Barcelona) with hardly any tides and limited fetch.Crescentic bar dynamics have been analysed using a nearly 8-year dataset of time-exposure video images (October 2010 to August 2018). The crescentic bar events, including formation and destruction moments, have been detected using visual analysis. Wave conditions in front of the study site have been collected by propagating 2D spectra (measured by a permanent wave buoy in front of Barcelona harbour) using the SWAN spectral wave model. The first results indicate that there is a lot of morphodynamic variability at the study site, even for low-energetic wave conditions (Hm0 < 0.5 m). Tens of crescentic bar events, including formation, evolution and destruction, can be observed. The bars show a large variation in wavelength (ranging from 100 to 500 m), which is often related to splitting and merging of individual crescents. Furthermore, the results reveal a strong relation between crescentic bar formation and the initial configuration of the bathymetry. Crescentic bars develop often when the sandbar is located some distance from the shoreline, whilst they are hardly observed when the sandbar is located close to the shoreline. Further work (which will be presented at the conference) consists of a detailed analysis of bar characteristics, including their alongshore migration, and the quantification of the role of wave conditions (especially wave direction) on crescentic bar dynamics.References Garnier, R., Falqu&#233;s, A., Calvete, D., Thiebot, J., & Ribas, F. (2013). A mechanism for sandbar straightening by oblique wave incidence. Geophysical Research Letters, 40(11), 2726-2730. Price, T. D., & Ruessink, B. G. (2011). State dynamics of a double sandbar system. Continental Shelf Research, 31(6), 659-674. Van Enckevort, I. M. J., Ruessink, B. G., Coco, G., Suzuki, K., Turner, I. L., Plant, N. G., & Holman, R. A. (2004). Observations of nearshore crescentic sandbars. Journal of Geophysical Research: Oceans, 109(C6).

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AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

International Conference on Technics Technologies and Education ◽

10.15547/ictte.2019.02.041 ◽

2019 ◽

pp. 95-103

Author(s):

Krum Videnov ◽

Vanya Stoykova

Keyword(s):

Water Level ◽

Real Time ◽

Early Warning ◽

Water Sources ◽

Water Levels ◽

Water Level Fluctuations ◽

Level Monitoring ◽

Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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