Jentsje Wouter van der Meer

Van der Meer Consulting bv

The stability formula for rock slopes under wave attack was revised in Van der Meer (2021), replacing the mean period Tm with the spectral period Tm-1,0. This rewritten formula closely resembles the Modified Van der Meer formula as in the Rock Manual (2007), with differences primarily in coefficients and the use of H2% in the Rock Manual and H1/3 i...

Wave overtopping is not easy to measure in real field situations. A 12-years long program started in 2018 to measure wind, wave and water level conditions in a complex estuary, together with wave overtopping measurements at dikes. The first winter storm was measured on 8 January 2019 and first results were described in Van der Meer et al. (2019). W...

The mean wave overtopping discharge and extreme overtopping volumes were assessed for a double vertical wall solution, including the combined effect of the mutual distance and effect of parapets, also known as wave return walls or bullnoses. New empirical functions were derived for predicting the mean overtopping discharge and maximum overtopping v...

Vertical walls are designed and built to protect coastal areas or harbours. Typically, these structures are installed in relatively deep water where incoming waves are reflected without breaking. In such cases the available prediction methods for wave overtopping discharge are well established. When the relative water depth h/Hm0 becomes smaller, w...

A primary purpose of many coastal defences is to protect people from direct hazard due to wave overtopping. This is reflected by the use of an admissible overtopping as a key parameter in design or assessment of structures. Despite this long-established design driver, it is less than 20 years since guidance on admissible overtopping started to move...

The present paper deals with overtopping prediction for berm breakwaters in line with the EurOtop methodology. The basis for the paper is the recent advances proposed for EurOtop for conventional breakwaters with respect to the influence of the wave steepness and the crest width. New model tests have been performed to investigate the applicability...

This paper investigates the influence of a crown wall on wave overtopping on rubble mound breakwaters. Existing data is used to modify the EurOtop overtopping formula updated by Eldrup et al. (2022) to cover the influence of the crown wall. The effect of raising the wall above the armour crest (elevated wall) or lowering the wall below the armour c...

New data was collected in the wave flumes of Ghent University and Aalborg University on wave overtopping discharges over rubble mound structures, focusing on the influence of (large) crest width and surface roughness in combination with wave period. Combining these new data with existing data, analysis has led to the improvement of the guidance for...

From 2007 wave overtopping tests with the Wave Overtopping Simulator (Van der Meer et al, 2008) have been performed on real dikes in order to determine the strength of grass covers against loads from wave overtopping. Over 15 different locations and over 50 different test sections have been tested. Most of these large scale tests have been performe...

In Van der Meer (2021) the stability formula for rock slopes under wave attack has been rewritten to remove the mean period Tm and to include the spectral period Tm-1,0. This formula is now identical to the Modified Van der Meer formula in the Rock Manual (2007 – Eqs 5.139 and 5.140), except for its coefficients and the use of H2 percent in the Roc...

This extended abstract contains two topics: stability of a pitched rock slope (in contrast to randomly placed rock) and mitigation of excessive wave overtopping at an existing rock slope. The stability of a single pitched rock layer could reasonably well be predicted by the Van der Meer formula. The criteria for start of damage and failure, however...

This work presents the results of an investigation on how wave overtopping at a near-vertical seawall at the back of a sandy foreshore is influenced by sequences of erosive storms. The experiments were carried out in the Large Wave Flume (GWK) at Leibniz University, Hannover (Germany). The tested layout consisted of a near-vertical 10/1 seawall and...

Wave overtopping formulae, which often underlie coastal hazard early warning systems, are typically parameterised using wave conditions at the toe of the structure. For very shallow conditions where significant wave breaking occurs over the foreshore, this usually requires computationally-demanding numerical models—and practitioners skilled in thei...

In this paper existing guidelines to predict wave overtopping on rubble mound breakwaters and coastal structures are modified and improved with respect to the influence of the roughness and crest width. Data from recently made model tests and existing data are combined to demonstrate the need for modifying these formulations in EurOtop. A new reduc...

Admissible wave overtopping is a key parameter in design specifications and also in safety assessments of the crest level of many coastal structures. This paper considers the hazard to people/pedestrians by post-wave overtopping flow over a horizontal surface, like a dike or breakwater crest, or a boulevard. Such flow is given by a flow velocity an...

Many coastlines around the world are protected by dikes with shallow foreshores (e.g. salt marshes and mudflats) that attenuate storm waves and are expected to reduce the likelihood and volume of waves overtopping the dikes behind them. However, most of the studies to date that assessed their effectiveness have excluded the influence of infragravit...

This paper presents the first field measurements with an innovative laser scanner system, during an actual severe winter storm with very oblique wave attack. The goal of this paper is to validate this innovative system for measuring wave run-up and wave overtopping parameters during storms with very oblique wave attack. The paper describes the anal...

The state-of-the-art formulas for mean wave overtopping (q) assessment typically require wave conditions at the toe of the structure as input. However, for structures built either on land or in very shallow water, obtaining accurate estimates of wave height and period at the structure toe often proves difficult and requires the use of either physic...

Many coastlines around the world are protected by coastal dikes fronted by shallow foreshores (e.g. saltmarshes and mudflats) that attenuate storm waves and are expected to reduce the likelihood of waves overtopping the dikes behind them. However, most of the studies to-date that assessed their effectiveness have excluded the influence of infragrav...

Wave overtopping is typically measured in the field using overtopping tanks. In this paper, an alternative system is developed that uses two laser scanners. The system also measures wave run-up, as well as run-up depths and velocities, both during perpendicular and oblique waves on a dike in the field. The paper considers the first calibration test...

A dike or levee will protect a polder to build in a tropical country against coastal flooding. To ensure that the performance of the dike is in accordance with the safety standard, wave overtopping tests with a wave overtopping simulator have been performed on a mock-up dike. These wave overtopping tests will guide the selection of the grass specie...

Oosterlo et al. (2019) developed a system using two terrestrial laser scanners, which can measure run-up heights, depths and velocities of waves on a dike in field situations. The system has now been placed next to two overtopping tanks on a dike in the Eems-Dollard estuary in the Netherlands to measure during actual severe winter storms. The goal...

Despite the widely recognized role of infragravity (IG) waves in many often-hazardous nearshore processes, spectral wave models , which exclude IG-wave dynamics, are often used in the design and assessment of coastal dikes. Consequently, the safety of these structures in environments where IG waves dominate remains uncertain. Here, we combine physi...

To accurately predict the consequences of nearshore waves, coastal engineers often employ numerical models. A variety of these models, broadly classified as either phase-resolving or phase-averaged, exist; each with strengths and limitations owing to the physical schematization of processes within them. Models which resolve the vertical flow struct...

Practitioners often employ diverse, though not always thoroughly validated, numerical models to directly or indirectly estimate wave overtopping (q) at sloping structures. These models, broadly classified as either phase-resolving or phase-averaged, each have strengths and limitations owing to the physical schematization of processes within them. M...

Wave overtopping is commonly measured using overtopping tanks. In this paper, an alternative system is developed by using two laser scanners. It measures wave run-up, as well as layer thicknesses and front velocities, both during normally and obliquely incident waves on a dike in the field. The paper considers the first field validation tests with...

The Eems-Dollard estuary is part of the shallow Wadden Sea in the north of the Netherlands. This highly complex estuary consists of deep channels and tidal flats. These complexities pose a challenge for the numerical models that determine the design wave conditions at the flood defences in the area. Of particular interest is the dike section north...

Wave overtopping is commonly measured using overtopping tanks. In this paper, an alternative system is developed by using two laser scanners. It measures wave run-up, as well as layer thicknesses and front velocities, both during normally and obliquely incident waves on a dike in the field. The paper considers the first field validation tests with...

While the significance of infragravity waves (IG) in many---often-hazardous---nearshore processes is widely-recognized, many of the empirical and numerical models used in dike safety assessments do not (directly) consider their contribution. Here, we combine physical and numerical modelling to better understand the factors that contribute to the do...

This work presents the results of an experimental investigation on the effects of a sequence of storms on wave over-topping at a nearly vertical battered seawall at the back of a sandy foreshore. The experiments were carried out in the Large Wave Flume (GWK) at Leibniz Universität Hannover (Germany), as part of the research project ICODEP (Impact o...

This work presents the results of an experimental investigation on the effects of a sequence of storms on wave overtopping at a nearly vertical battered seawall at the back of a sandy foreshore. The experiments were carried out in the Large Wave Flume (GWK) at Leibniz Universität Hannover (Germany), as part of the research project ICODEP (Impact of...

It is common for the local sea state in coastal waters to be a complex combination of waves due to local and recent wind (the “sea”) and long period waves resulting from earlier weather systems, which have travelled many 100s of km with little attenuation of these very long waves (the “swell”). Sea and swell may have very different directions and p...

The dike in Den Oever has to be improved. To keep the dike as low as possible and to make it suitable for other uses, the choice was made to install a stepped revetment on the sea side. In order to determine the design wave loading, scale model tests and tests at full scale were performed. The comparison shows that loads, as a result of model and s...

Large scale tests were performed in the large scale facility GWK at Hannover, Germany, within the HYDRALAB+ project ICODEP: Impact of Changing fOreshore on flood DEfence Performance. The test set-up consisted of a relatively steep 1:15 sandy beach profile in front of a battered seawall with 10:1 slope (almost vertical). Two storms were generated, S...

Ile de Ré is a low-lying island located on the western edge of France. The extreme storm Xynthia (February 2010), was one of the most destructive natural disasters in this area, causing severe damages and breaches on coastal protections and one third of the total area of the island was flooded. Storm impact feedback showed that wave overtopping and...

This paper considers the Eems-Dollard estuary in the north of the Netherlands, which is part of the shallow shelf sea the Wadden Sea. This estuary is a highly complex area with tidal flats and deep channels and is characterised by an offshore directed wind, posing a challenge to wave prediction models. As little measurements are available, a measur...

This paper considers the Eems-Dollard estuary in the north of the Netherlands, which is part of the shallow shelf sea the Wadden Sea. This estuary is a highly complex area with tidal flats and deep channels and is characterised by an offshore directed wind, posing a challenge to wave prediction models. As little measurements are available, a measur...

Shallow foreshores in front of coastal dikes can reduce the probability of dike failure due to wave overtopping. A probabilistic model framework is presented, which is capable of including complex hydrodynamics like infragravity waves, and morphological changes of a sandy foreshore during severe storms in the calculations of the probability of dike...

This chapter describes the processes of wave overtopping at sea defense and related coastal or shoreline structures. It introduces a range of methods to calculate mean overtopping discharges, individual and maximum overtopping volumes, and the proportion of waves overtopping a seawall. It describes the principal hazards from wave overtopping and wi...

Berm breakwaters may be a good alternative for rock armored slopes and even concrete armored slopes or breakwaters. Guidance on berm breakwater design, including large rock quarrying, was lacking as this type of breakwater does not belong to the conventional designs of rock and concrete armor. Some guidance by the authors became available in recent...

Wave overtopping prediction at vertical structures in earlier days was mainly based on caisson-type structures in relatively deep water. Recent research in many EU-projects has been concentrated on shallower water with waves breaking onto the structure as well. It has led to the definition of two situations: nonimpulsive and the most severe impulsi...

Wave overtopping and to a lesser extent wave run-up for armored rubble slopes and mounds have been subject to a number of investigations in the past. The objective of the present chapter is to summarize existing information to be present as a closed guidance on the use of wave run-up and wave overtopping formulae for a wide range of possible applic...

Single layer concrete armor systems are being widely used nowadays in the design of rubble mound breakwaters. Recently, a new concrete armor unit has been developed and applied as single layer armor system in the repair works of one damaged breakwater at Al Fujeirah, UAE. It has a symmetrical shape, in contrast to most other units. Modern single la...

A new and symmetrical single layer armour unit, the crablock, has been designed in the U.A.E. One breakwater was reconstructed with crablock, but very limited testing had been performed. Just to become more acquainted with this new unit, pre-competitive research at a university has been performed, which is the subject of this paper. Being a new arm...

Structural and functional aspects of berm breakwaters have been covered in earlier papers by the present authors and with geometrical design rules for berm breakwaters presented at ICCE 2014, this paper mainly focuses on design aspects related to armourstone, armourstone grading, quarrying for armourstone, and construction aspects of berm breakwate...

A new wave run-up simulator has been designed, constructed, calibrated and used for testing of the seaward face of dikes. The upper part of dikes or levees often have a clay layer with a grass cover. The new device is able to test the strength of the grass cover under simulation of up-rushing waves for pre-defined storm conditions. The cumulative o...

The so-called post-overtopping processes are of wide interest for coastal engineers. Dedicated middle-scale tests have been carried out to measure impacts of an overtopped wave on a storm wall at low freeboard coastal structures. A smooth dike slope and a vertical wall, both with a promenade at crest level and a storm wall at the end of it, have be...

The paper demonstrates the use of the geometrical design rules for berm breakwaters in a potential project in Greenland. With practically no information about the sizes of armourstone that could be used for the design, the initial phase of the study looked at the full range of the stability parameter Hs/ΔDn50 of 1.7 to 3.0 for the design wave heig...

A new Wave Run-up Simulator has been designed, constructed, calibrated and used for testing of the seaward face of dikes. The upper part of dikes or levees often have a clay layer with a grass cover. The new device is able to test the strength of the grass cover under simulation of up-rushing waves for pre-defined storm conditions. The cumulative o...

A second edition of the EurOtop manual, a manual on wave overtopping of sea defenses and related structures, became available as pre-release in October 2016 on the website www.overtopping-manual.com. One of the improvements in this manual is based on the material in the current paper: how wave walls can reduce wave overtopping discharges. The base...

DETERMINING THE CRITICAL VELOCITY OF GRASS SODS FOR WAVE OVERTOPPING BY A GRASS PULLING DEVICE Roel Bijlard, Delft University of Technology, roelbijlard@gmail.com Gosse Jan Steendam, INFRAM International, gosse.jan.steendam@infram.nl Henk Jan Verhagen, Delft University of Technology, h.j.verhagen@tudelft.nl Jentsje van der Meer, Van der Meer Consul...

Quite some new insights on wave overtopping were achieved since the first submission of the EurOtop Manual in 2007, which have now resulted in a second edition of this Manual. A major improvement has been made on the understanding of wave by wave overtopping and tolerable wave overtopping that is connected to it. Many videos are available on the ov...

This contribution presents a new Artificial Neural Network (ANN) tool that is able to predict the main parameters describing the wave-structure interaction processes: the mean wave overtopping discharge ((Formula presented.)), the wave transmission and wave reflection coefficients ((Formula presented.) and (Formula presented.)). This ANN tool is tr...

This paper presents an Artificial Neural Network (ANN) to predict the wave overtopping discharge at coastal and harbour structures for a variety of wave conditions and complex geometries. The goal of this work is to provide a robust tool in both extreme and tolerable overtopping conditions, starting from the ANN recently developed by the authors fo...

The goal of this work is to present a synthesis of the improvements and updates developed to deliver the final version of the ANN tool adopted by the second edition of the wave overtopping manual, EurOtop, released on the internet in 2016. This tool consists of three identical but independent ANNs able to predict the main parameters representative...

Keynote presentation that summarises the improved EurOtop 2 overtopping manual

Modern design of berm breakwaters began about thirty years ago. However, to date, there has been a lack of a well-established, formal design methodology on berm breakwaters. The authors Dr Jentsje van der Meer and Sigurdur Sigurdarson combine over 40 years of collective experience working with breakwaters to put forward a design framework in Design...

In the design of coastal structures like rubble mound breakwaters, nowadays single layer systems using concrete armour units have become more common practice compared to conventional two layer systems. Recently, a new and symmetrical single layer concrete armour unit, the crablock, has been invented in the UAE. In general, placement of single layer...

The so-called post-overtopping processes are of wide interest for coastal engineers. Dedicated middle-scale tests have been carried out to measure impacts of an overtopped wave on a storm wall at low freeboard coastal structures. A smooth dike slope and a vertical wall, both with a promenade at crest level and a storm wall at the end of it, have be...