‘This is really intense research’

Researchers from all over the world have gathered on a Dutch beach and put on their wetsuits. They are measuring currents, waves and sand erosion as part of a measuring campaing organised by TU Delft.

A couple of girls in wetsuits are doing stretching exercises on the beach whilst a muscly guy dives into the waves with a bodyboard. A little further into the sea, a young man rushes by on a jet ski and tries to gain attention.

Though the young women are from the United Stated, this is no scene from Baywatch. Rather it is the setting of a research project that is situated just off the coast of Zuid Holland, at the Sand Engine, an artificial peninsula created in 2011. Normally sand is being replaced on the coast every year to counter erosion. The idea now is to instead let the sand from the peninsula be distributed along the coast between Hoek van Holland and Scheveningen naturally by wind, waves and currents for the coming twenty years.

Americans, South Africans, Swedes; researchers from all over the world have gathered here for a six-week period. They participate in a measuring campaign organised by TU Delft researchers and have deployed all kinds of equipment, including current sensors, drifters, sonar tools and even a drone, to do measurements on coastal erosion, bathymetry and waves.

One of the most impressive set of tools are the 42 instruments that measure the currents near the bottom of the sea. They are simple tilt sensors, comparable to those in smart phones, and thus very cheap devices. They are anchored with paving stones. A myriad of buoys marks their location. A poor fisherman, who hadn’t heard of the research project, recently found himself amidst of all this equipment, to his great surprise. The Sand Engine is a popular fishing ground.

PhD student Meagan Wengrove, from the University of New Hampshire, has her diving goggles on. She just helped collecting drifters that were thrown into the sea to measure the currents. “And now I have to go and put new batteries on my instrument which is at two meters depth and recuperate someone else’s camera’s that were snowed under with sand”, she explains. “This is really intense research”, she laughs. “I have been swimming competitively for fifteen years. So this should be no problem.”

Wengrove is interested in the sand ripples on the oceans floor. “I want to understand how storms and currents influence their shape. Models in oceanography usually don’t account for these rapid small scale changes. But they might be of importance.”

Wengrove is one of many American researchers who took base at the Sand Engine. She is accompanied by colleagues from the Scripps Institute of Oceanography in San Diego, the Oregon State University and the Universities of Miami and Washington.

What makes this Dutch measuring campaign so interesting for these researchers to come over all the way over from the United States? Wengrove: “People here are collecting many different types of data, which combined can give us new insights. Some look at small scale processes, like myself, whilst others measure large scale developments. Take that guy on the jet ski for instance”, she says whilst pointing to the distance. “He has been doing measurements on the bathymetry with sonar at a regular basis for months in a row.”

Does this new natural sand replacement technique in itself also attracted international attention? “Sand engines could be interesting in some parts of the United States”, says Wengrove. “Take Long Island and New Orleans for instance. These are also densely populated areas where they have problems with keeping land.”

According to Bonnie Ludka this spot in The Netherlands is unique. “There is no other sand engine in the world”, says the researcher from Scripps Institute of Oceanography in San Diego who is packed in neoprene from head to toe and still shivering. “It could also be interesting for the US. We do sand nourishment as well. Near the coast of San Diego amongst others.”

Wengrove in the mean time has gone back into the water. She is accompanied by coastal engineer Dr. Matthieu de Schipper (CEGfaculty), who is one of the organisers of the measuring feast, which is officially called MegaPEX2014. Both carry with them a jerrycan of bilious green dye. A drone hovering high above them observes the huge green spills that appear when they empty their cans. Again a technique to study currents.

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