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Dieren en planten

Water en land

Landforms   Coastal areas   Rocky coasts   Tidal flats and shallows   Salt marshes   Beaches   

Mens en Milieu

Sea level rise   Water   Water currents   Tides and water levels   Waves   Tsunamis in the North Sea   Water management   Coastal protection   Coastal erosion   Flood disasters   The Wadden Plan   Breakwaters   Sand nourishments   
Breaking wave, Marijke de Boer

Waves

The wind blowing over the sea surface causes a wave motion on the water surface. During a storm, waves in the North Sea can reach several meters in height. Sometimes, waves will grow to more than 6 meters high not all that far off the shore. Locally, the force with which waves roll onto the shore during a storm can cause massive damage to the dunes. An extreme example of a large wave is the tsunami, caused by underwater earthquakes.

  • Safety

    Changes in the wind climate can have far-reaching consequences for Dutch coastal defence. An increase in the wind by 10% appears to have as much effect as a sea level rise of 60 centimeters. On the North Holland coast, several sea barriers have been constructed to withstand a storm which could raise the water level to 4.70 meters above NAP (Normal Amsterdam Level). The accompanying waves and wave tumult on the dikes have made it necessary to build the dikes so that the tops reach more than 11 meters above NAP. A similar height also holds for the dunes.