Surfer's paradise

An artificial reef creates great waves at Scheve-ningen Beach, heralds NRC Handelsblad.

depunt@Scheveningen 23-2-2010, by quintblom

Protecting the country against flooding while still retaining good surf spots along the coast had long seemed a contradiction in terms. Every year huge quantities of sand need to be dumped on Dutch beaches to support the dunes, which are constantly eroding. These piles of dumped sand are washed away by the sea and strengthen the dunes further along the coastline.
Surfers were never too keen about this dumping process, because shortly after the sand was dumped the waves they ride on would mostly disappear. Because of the extra sand, the beaches become steeper, and this leads to the waves breaking much more suddenly.

Nevertheless, at the moment the surfer dudes in the coastal town of Scheveningen are now breaking personal records, despite the fact that extra sand has recently been added to local beaches. Large amounts of this sand were poured on an underwater embankment, turning it into a reef that runs perpendicular to the coastline and creates a great swell. The waves start curling at the tip of the reef and continue doing so all the way to the beach. Reefs like these (but then natural reefs) are common at many of top surf spots around the world.

Coastal engineer and TU alumnus, Erik van Ettinger, of the company SurfReefs, together with PhD students, Sierd de Vries, Matthieu de Schipper and Martijn Henriques (faculty of Civil Engineering and Geosciences), designed this reef that was commissioned by the municipality. “I was there in the water myself recently”, says De Vries, who is a passionate surfer. “Talks about creating this reef started three years ago and now it’s accomplished. It’s really amazing how well it works. The waves are better now than before the sand was dumped. Normally you’re happy if you get to ride a wave for about 10 seconds. Now however we get rides of up to 24 seconds. It’s unprecedented.”
Unfortunately however this great point break is only temporary, since the sand is being washed away gradually. But instead of fearing such coastal protection measures, surfers will now be looking forward to them.
Before they could design the artificial reef, the researchers had to investigate the sedimentation processes along the coast. With a jet-ski, loaded with high tech and water-tight electronics, they surveyed the seabed for months. Using what is known as a Doppler current profiler, they measured the currents at different depths, while also using an echo sounder to make depth profiles.
“We’re now assigned to monitor the reef and investigate how much the waves have been ameliorated and how the reef could be improved”, De Vries concludes.