The Dutch Built a Massive Wave Machine to Study Flooding
The story goes like this: A little Dutch boy spots a hole in a dike, and sticks his finger in to plug it up. He stays there for days and nights, ultimately saving his country from watery ruin. Apocryphal? Well, yeah. But the people of the Low Country have been preoccupied with keeping the ocean at bay for centuries, an interest that has only intensified with the threat of climate change. That means designing better infrastructure—which is why a Dutch company, Deltares, has built a machine that generates the world’s biggest artificial waves.
Their machine, the Delta Flume, works like this: Pistons rhythmically shove around more than two million gallons of water in a 900-foot-long concrete trough, like a giant toddler splashing back and forth in a bathtub. Eventually, the waves double back on themselves to form monsters up to 15 feet high.
The project isn’t about making really big waves for the sake of making really big waves, though, says Dan Cox, a coastal engineering professor at Oregon State University, which houses the largest research wave machine in North America. The purpose of wave machines is pretty simple: to see how human-made structures—breakwaters, seawalls, giant concrete blocks—stand up to crashing waves and giant storms before millions of people trust them to protect them from the elements. For wave machines, “bigger is better, because you don’t have to worry about scale effects,” Cox says. A giant machine sidesteps factors like surface tension and sand grain size that, at the wrong scale, could screw up results.
The Delta Flume comes as part of decades of disaster prep in the Netherlands. The Dutch have spent the last half-century constructing big flood-control infrastructure including the Delta Works, a country-wide network of dams, dikes, locks, levees, and storm surge barriers. They closely measure rainfall and water levels, and open and close their floodgates accordingly. They’ve designated giant sacrificial areas they can let flood, and have made water management plans for the rest of the century. And they kill the muskrats that nest in the levees. “The Dutch have written the book on modern coastal flood protection,” says Patrick Lynett, a coastal engineer at the University of Southern California.
Contrast that with the US, which focuses more on flooding relief than prevention. “We rely more on beach nourishment and avoidance, while Holland takes the ‘hold the line’ approach,” Cox says. That’s a problem that’ll get worse with climate change: South Carolina faced flooding earlier this month from rains NOAA called a “thousand-year deluge,” and New Orleans, Miami, and other coastal cities are looking at inundation in a couple centuries. But we don’t have that same massive infrastructure the Netherlands does, Cox says, which is worrying. America has some catching up to do, and no little Dutch boy is going to come save the country.