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Dieren en planten

Water en land

Mens en Milieu

Coastal protection   Sand nourishments   
Sand nourishment on Texel, Foto Fitis, www.fotofitis.nl

Sand nourishments along the Dutch coast

At many areas along the Dutch coast, more sand washes away than washes ashore. The sandbanks in front of the coast are declining, the edges are growing steeper and the beaches are narrowing. During storm, the sea can easily remove sand from the outer row of dunes. The solution is simple but also laborious: bring more sand into the area. Since 1979, the Dutch Department of Public Works has been compensating coastal erosion by spouting sand onto the beaches of the Dutch coast. This has been the major form of coastal protection since 1990; the goal is to maintain the coastline of 1990.

On Texel


Beach nourishment Texel, ca.1995, Ecomare, Sytske Dijksen

On Texel, the first beach nourishment took place in 1979 on Eierland. In 1984 and 1985, extra sand was added to the beaches of De Koog and Eierland. Since 1990, two to three million cubic meters of sand are sprayed onto the beaches of Texel almost every year. As far as coastal protection is concerned, Texel is the most expensive ground in the Netherlands. In order to limit the costs, a 550-meter long dam was constructed perpendicular to the coast near Eierland in 1995. This helps to hold down the sand in the north. The first forebank nourishments on Texel took place in 2002 and 2003. After 2 years, they didn't live up to expectations. Sand  must still be regularly supplemented, either on the forebanks or directly on the beach. 

  • Where from and where to
    Beach nourishment, Ecomare

    The sand is extracted from areas located a number of kilometers away from the shore where the sea is at least 20 meters deep. Sand from dredged channels is also used for nourishments. Between 1990 and 2000, around 7 million cubic meters of sand was extracted annually. Between 2000 and 2010, that was around 12 million cubic meters per year. Coastal protectors expect the amount to soon increase to 20 million cubic meters per year. The reason is sea-level rise.
    Even the beaches of the eastern and northern Frisian Islands are regularly supplied with new sand. In 1998/1999, almost all of the beaches of Baltrum and Wangerooge (in Germany) were lost during heavy winter storms. Even Sylt is continually threatened with losing sand.

  • Sucked-up benthic animals and treasures
    Many stones are spouted onto the beach, Foto Fitis, www.fotofitis.nl

    The sand used for beach nourishments is taken from areas far away from the coastline at a depth of more than 20 meters. You can see that the sand comes from elsewhere. It is brownish and rich in calcium. Benthic animals normally are not found very often on the beach are among the sucked-up sand. Benthic animals and fish, such as plaice and turbot land on the beach after a trip through the hopper, making an easy meal for coastal birds. Fossil bones, early-Medieval coins, silver rings and flint stone instruments are also transported. They come from places in the North Sea which used to be land and where people used to live, or from ships. During sand nourishments in Zeeland, fossilized shark and ray teeth are often transported with the sand to the beach. This sand comes from a sandbank situated close to the coast.

  • Forebank nourishments
    A fore bank nourishment, Foto Fitis, www.fotofitis.nl

    Underwater nourishment was performed for the first time in the Netherlands in 1993, off the coast of Terschelling. Forebank nourishments are cheaper than beach nourishments since the sand doesn't have to be transported as far. In addition, there are no inconveniences on the beach.
    Two million cubic meters of sand were dumped off of the Terschelling coast, at a depth of 6 meters. Based on experience in Australia and the United States, it was expected that it would help end the receding shoreline. This expectation was proven true.

  • Ecological effects

    The effects of the underwater nourishments on Terschelling were studied using a grant from the European Community. The research concentrated on the extent of the disturbance on the sea life living on the underwater bank and the area where the sand was extracted. Approximately six months after the nourishment, the density of the benthic fauna was around half of what it was beforehand. Shellfish had declined; worms and crustaceans recovered more quickly. Two years later, the bottom was more or less back to normal. Only the cut trough shells, the banded wedge shell and the sea potato did not recover.

    Fish species that swim in coastal waters (plaice, sole, dab, brill, turbot) eat mainly worms and crustaceans, species which recover quickly. The risks for shellfish-consuming diving ducks, such as common scoters, are greater. When such a bank has been disturbed by sand nourishments, it can take several years before the ducks can find food again.

    Comparable effects occur in areas where sand is extracted. Worms and crustaceans recover quickly here as well, while considerable damage is done to long-living species, such as bivalve shellfish and sea potatoes.

    Because sand nourishments have ecological and geological consequences, the Natura 2000 regulation requires a study of the effects on the sea fauna.

  • Sand motor
    Sand Motor under construction, Layla Wijsmuller

    A large artificial sandbank was laid just in front of the coast a few kilometers southwest of The Hague. Construction began on January 17 2011 and the sandbank was 'ready for use' later that year on November 24. The explicit intention is for the sea to eat away the sand and to place it at weaker spots along the Holland coastline. Making such a sandbank is cheaper than all the sand nourishments, which according to coastal protectors will become redundant. Hydraulic engineers expect the Sand Motor to end after 20 years.