scholarly journals NEW DESIGN OF THE BALTRUM DUNE REVETMENT BASED ON HYDRAULIC MODEL TESTS

2012 ◽  
Vol 1 (33) ◽  
pp. 75
Author(s):  
Frank Thorenz ◽  
Holger Blum ◽  
Andreas Kortenhaus

The sandy barrier island of Baltrum is located in the north-western part of the German Federal State Lower Saxony in the North Sea. The north-western part of the island is protected by a dune revetment against storm surges and erosion. In order to determine the functionality and loading of the construction under design storm surge conditions and investigate planning alternatives, numerical modeling of sea state conditions in combination with hydraulical model tests for the construction were executed. Measured overtopping rates of up to 125 l/(s.m) and loads up to 150 kPa showed the necessity to strengthen and heighten the initial construction. A combination of wall elements for wave run-up and overtopping reduction in combination with a crest wall were designed in order to meet the technical demands of coastal defence as well as the touristical needs of an important recreation locality.

2011 ◽  
Vol 1 (5) ◽  
pp. 34
Author(s):  
J. B. Schijf

The North Sea is a shallow sea and therefore it is very sensitive to wind effects. As a result the water levels along the coasts are, in addition to the tidal oscillations subject to a considerable wind setup and exceptionally severe gales throughout history have been accompanied by inundations of the low-lying regions bordering the North Sea, in particular its southern part. No stretch of coast has suffered more than that belonging to the Netherlands and the adjacent parts of Belgium and North Western Germany. Several factors combine to bestow on us this doubtful privilege.


Author(s):  
Dieter Vanneste ◽  
Wim Van Hoydonck ◽  
Daphné Thoon

In the framework of the EU Floods Directive, Flanders Hydraulics Research (FHR) is performing flood modeling studies to evaluate the flood risk along the Belgian coast due to extreme storm surges on the North Sea. Thereto, amongst others, the failure behavior of quay walls in the coastal ports must be determined. Computing the landward non-impulsive wave overtopping discharge over a broad quay, in some cases combined with overflow, on which a flood wall can be present at large distance [O (100 m)] from the front edge poses a particular challenge. This matter, to the authors’ knowledge, is not covered in existing literature, e.g. the European Overtopping Manual. It is also not possible to apply the method for reduction of wave overtopping over a wide crest according to Verwaest et al. (2010), since it was developed for breaking waves on a shallow foreshore overtopping a sloping dike, requiring the determination of a run-up level. It is clear that the landward water flow on the quay should be investigated in more detail, as it is characterized by bottom friction and possible inertia due interaction with the flow reflected at the flood wall. To this end, the CFD toolbox OpenFOAM is used to model the final discharges at the landward side of the quay.


1984 ◽  
Vol 16 (3-4) ◽  
pp. 477-484
Author(s):  
H L Wakeling

The paper reviews various methods of flood control in the lower Yare Basin which has been subject to serious flooding caused by storm surges in the North Sea and by fluvial floods. This area is known as the Broads and is an area of scenic beauty, includes many sites of scientific interest and is a popular tourist area. The effects of the different flood control options on the environment are discussed. The primary economic justification for flood prevention was found to arise from the conversion of poor quality marsh grazing land to arable or improved pasture once the risk of saline flooding was removed. The consequences of this change in land use on the flora and fauna have aroused much concern among environmentalists.


2018 ◽  
Vol 10 (7) ◽  
pp. 1100 ◽  
Author(s):  
Ferdinando Reale ◽  
Fabio Dentale ◽  
Eugenio Carratelli ◽  
Luciana Fenoglio-Marc

AmS-Skrifter ◽  
2020 ◽  
pp. 133-143
Author(s):  
Aoife Daly

The precise dating and determination of the source of timbers in shipwrecks found around the coasts of the North Sea and the Baltic Sea, through dendrochronology allows us to see connections between north and  south, east and west throughout the region and to a high chronological precision. In this paper we take a look at results of recent analyses of timber from ships, and timber and barrel cargoes, to try to draw a chronological picture, from the twelfth to seventeenth centuries, of links between regions, through transport in oak ships and trade of timber. Archaeological finds of oak from timber cargos in shipwrecks and fine art objects (painted panels and sculpture) show the extent to which timber was shipped from Hanseatic towns along the southern Baltic coast, to western and north-western Europe.


Records of sea level for several North Sea ports for the winter of 1953-4 have been in vestigated. They were split into 14-day intervals, and each 14-day record was Fourieranalyzed to determine if any non-astronomical periods were present. There was evidence of some activity between 40 and 50 h period, and a determination of the phase angles at different ports showed that the activity could be due to a disturbance travelling southwards from the north of the North Sea. The disturbance was partly reflected somewhere near the line from Lowestoft to Flushing, so that one part returned past Flushing and Esbjerg towards Bergen while the other part travelled towards Dover, and there was evidence of its existence on the sea-current records taken near St Margaret's Bay. These results were confirmed by subtracting the predicted astronomical tidal levels from the observed values of sea level and cross-correlating the residuals so obtained for each port with those found at Lowestoft. The residuals at Lowestoft and Aberdeen were compared with the meteorological conditions, and it was found that, although they could be attributed to a large extent to conditions within the North Sea, there was an additional effect due to a travelling surge which was of the same order of magnitude at both Lowestoft and Aberdeen and which was closely related to the rate of change with time of the atmospheric pressure difference between Wick and Bergen.


Author(s):  
Anne Haour

This chapter explains the coverage of this book, which is about the comparison of rulers, warriors, traders, and clerics on the central Sahel and the North Sea region. It argues that there was more similarity between north-western Europe and the central Sahel in the few centuries either side of AD 1001 than has hitherto been recognised, and maintains that the nature of the sources has obscured these formative times and left them in the shadow of organised structures. It discusses the interconnectedness of central Sahel and north-west Europe through contacts and shared pre-industrial nature.


Ocean Science ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 369-378 ◽  
Author(s):  
A. Sterl ◽  
H. van den Brink ◽  
H. de Vries ◽  
R. Haarsma ◽  
E. van Meijgaard

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.


1895 ◽  
Vol 37 (1) ◽  
pp. 127-149
Author(s):  
James Geikie

For many years geologists have recognised the occurrence of at least two boulder-clays in the British Islands and the corresponding latitudes of the Continent. It is no longer doubted that these are the products of two separate and distinct glacial epochs. This has been demonstrated by the appearance of intercalated deposits of terrestrial, freshwater, or, as the case may be, marine origin. Such interglacial accumulations have been met with again and again in Britain, and they have likewise been detected at many places on the Continent, between the border of the North Sea and the heart of Russia. Their organic contents indicate in some cases cold climatic conditions; in others, they imply a climate not less temperate or even more genial than that which now obtains in the regions where they occur. Nor are such interglacial beds confined to northern and north-western Europe. In the Alpine Lands of the central and southern regions of our Continent they are equally well developed. Impressed by the growing strength of the evidence, it is no wonder that geologists, after a season of doubt, should at last agree in the conclusion that the glacial conditions of the Pleistocene period were interrupted by at least one protracted interglacial epoch. Not a few observers go further, and maintain that the evidence indicates more than this. They hold that three or even more glacial epochs supervened in Pleistocene times. This is the conclusion I reached many years ago, and I now purpose reviewing the evidence which has accumulated since then, in order to show how far it goes to support that conclusion.


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