How the Dutch are building coastal protection for less — with nature’s help
This is the second installment of a Times-Picayune and Advocate series exploring how the Netherlands’ climate change adaptation strategies could be a model for the Louisiana coast.
The series was produced in collaboration with WWNO New Orleans Public Radio and Climate Central, and is part of the Pulitzer Center’s Connected Coastlines reporting initiative. For more information, go to pulitzercenter.org/connected-coastlines
By Tristan Baurick, The Times-Picayune | New Orleans Advocate and Climate Central
TER HEIJDE, The Netherlands — With a surfboard strapped to his feet and the reins of a giant kite in his hands, Daan Vijverberg skimmed over whitecaps on the Netherlands’ windy south coast. Nearby, other kiteboarders caught gusts strong enough to fling their wetsuited bodies several feet into the air.
“It’s addictive,” Vijverberg said, emerging from the water with a red face and the sniffles. “I have to come two, three times a week.”
The Dutch government made this stretch of coast a magnet for kiteboarders and other beachgoers a few years ago when it dropped off an immense pile of sand.
About 28 million cubic yards of sand — enough to fill the Mercedes-Benz Superdome six times — was dredged from the seafloor and piped here, forming a lagoon and pushing the beach about a half-mile into the North Sea. During the summer, the hook-shaped peninsula draws thousands of walkers, sunbathers and surfers — both the kite and traditional varieties.
But the goal of this monumental, $55 million sandscaping project was protection, not recreation. Called the Zandmotor (Sand Motor in English), the project is the world’s largest experiment in coastal storm and flood defense at a time when climate change is causing seas to rise and storms to intensify.
“I thought this was an accident,” Vijverberg said. “I thought they were dropping sand off for something else and they never came back. I hope they don’t change it.”
But change is happening with every wave and puff of wind.
By design and over time, the project relies on natural forces to be the “motor” that spreads the sand along 13 miles of coast, adding about 3,500 acres of new beach and dunes as it does so. Wind, waves and currents do work that would otherwise require a repeated process of dredging, dumping and spreading with tractors and other heavy machinery along several miles of coastline.
The Sand Motor is a nature-based alternative to the Netherlands’ famed network of walls, levees and sea gates, and much cheaper than the vast, multimillion-dollar beach rebuilds Louisiana is undertaking along its sandy barrier islands and rapidly deteriorating coastline.
Where Louisiana’s projects seek to re-create almost precisely what was lost, the Dutch simply pile the sand in a strategic location where it will be pushed naturally into places where it will still provide protection. The method is slow — so it lasts longer — and it’s much cheaper.
“We dump it and leave it and let nature do the rest of the job for us,” said Carola van Gelder-Maas, a project manager for Rijkswaterstaat, the Dutch government’s water management agency.
On both the Louisiana and Dutch coasts, barrier islands and sandy beaches act as speed bumps, absorbing wind and wave power that would otherwise travel unimpeded through fragile wetlands and into towns and cities. Bulking up the Sand Motor’s section of coast protects The Hague, the Netherlands’ third-largest city, and a wider area of about 1 million people.
The Sand Motor is humming along nicely. After nearly a decade, recent assessments show the sand is moving according to plan. The initial hook-shaped peninsula has been worn down by the elements, retreating about 1,000 feet between 2011 and 2018. At the same time, about 5 miles of nearby coastline are now coated with a thick buffer of sand and naturally formed dunes.
Because the Sand Motor works slowly and doesn’t rely on heavy equipment to spread sand, plants and marine life have more time to adapt. And adapt they have. Biodiversity — the range of plants and animals — is much higher on the Sand Motor than other nearby beaches, according to a report by Delft University. The lagoon has acted as a nursery for fish; shellfish thrive in the tidelands; and at least 40 species of birds nest or hunt along the shore.
Also proliferating is marram, a beach grass that a recent Sand Motor study called “the greatest coastal engineer.” Spiky tufts of marram trap windblown sand and pile it into shore-toughening dunes. Marram is often planted by hand in other restoration projects, but the grass needed no encouragement to find its way to the Sand Motor.
“It’s almost like (the grasses) said, ‘Hey, this is what I know. I belong here,’ ” said Leo Linnartz, an ecologist with the Dutch conservation group ARK Nature.
The Sand Motor was expected to provide 20 years of protection before more sand was needed, but a recent analysis suggests it could last twice as long, van Gelder-Maas said.
“What we see now is that it will exceed 20 years, and we think it will be there for at least 40 years,” she said.
That’s because the sand moved much faster than expected during the first year but slowed below expectations every year since then.
“About 90% of the sand is still there and still moving but slowly,” she said. “So it is a real success. We don’t need to (add) sand like we used to do before the Sand Motor was there.”
The 13 miles of bulked-up beach will help the Dutch coastline stand up to erosion, storm surges, rising seas and subsidence, the natural compacting and sinking of the soil.
It’s a quartet of threats Louisianians know well.
The Netherlands and Louisiana both sit on low-lying river deltas fronting increasingly turbulent seas. Climate change has worsened storms on the North Sea, but they’re still small compared with the hurricanes that roar through the Gulf of Mexico. Still, the Netherlands is under constant threat from storms that can push waves into densely populated areas sitting several feet below sea level, or push into rivers and overwhelm levees.
Like the Netherlands, Louisiana is paying close attention to the increasingly worrisome projections for sea level rise. Between 2006 and 2015, seas rose at a rate nearly three times faster than they did during the last century, according to the latest United Nations climate change report.
Sea levels are expected to climb even faster, with risks amplified by sinking coastal lands. Even with moderate cuts to heat-trapping pollution, Louisiana’s sea levels are projected to rise by at least 4 feet by the end of the century. Under some high-pollution scenarios, the rise could exceed 7 feet.
More sand, less money
Louisiana has undertaken projects similar to the Sand Motor but paid far more money to move far less sand.
Over the past 20 years, Louisiana has spent more than $817 million pouring sand along its barrier islands and coastal headlands, bulking up 75 miles of beach and back-island marsh, according to a recent assessment by the state Coastal Protection and Restoration Authority.
The state plans to invest another $1.5 billion on sand-moving projects over the next 50 years as part of the Coastal Master Plan, an ambitious restoration and storm protection initiative with a total price tag of $50 billion.
Much of the money is drawn from a settlement with BP over the 2010 Deepwater Horizon oil disaster. But that money is finite, while the requirements of barrier island and headland restoration are ongoing. Even the largest, most expensive projects will have to be redone in 15 or 20 years. It’s unclear where the next batch of billions will come from, making it critically important for Louisiana to stretch the money it has as far as it can.
Louisiana’s biggest beach rebuild was on Whiskey Island, a slender, uninhabited island on the edge of Terrebonne Bay. Completed in 2018, the project spent $118 million dredging and spreading more than 15.8 million cubic yards of sand — enough to fill the Superdome three times.
The Sand Motor was completed for about half the money and managed to move nearly two times as much sand.
The comparison is even more unfavorable for another celebrated beach rebuild, the Caminada Headland project of 2017. Caminada’s 13 miles of restored beach protect the oil shipping hub Port Fourchon and La. 1, the only hurricane evacuation route for Grand Isle and other communities. It cost $216 million, nearly four times as much as the Sand Motor. Yet it moved just 8.8 million cubic yards of sand, the equivalent of two Superdomes to the Sand Motor’s six.
State coastal restoration experts are familiar with the Sand Motor but couldn’t answer why it costs them so much more to do so much less.
Greg Grandy, the Coastal Protection and Restoration Authority's deputy director and a former manager of barrier island restoration projects, guessed that Louisiana projects were more expensive because the sand had to travel a greater distance from source to restoration sites. Both the Whiskey Island and Sand Motor projects used an underwater pipeline to move sand. The pipeline distance for Whiskey was 10 miles. The Sand Motor distance was slightly more than 6 miles.
“I’m not sure why the Dutch can do it cheaper,” Grandy said. “It could be distance. The longer you drive the material, the more it costs. It’s like how a plane ticket to Seattle is more expensive than taking a flight to Dallas.”
Although sand transport is one of the most expensive elements of such projects, it doesn’t alone explain the difference in price tags. Moreover, the cost per mile of moving a cubic yard of sand was half as much for the Sand Motor as it was for the Whiskey Island project.
Vast cost differences are all too common when U.S. dredging projects are compared with ones in other countries, including the Netherlands and Belgium — low-lying nations that export dredging services around the world.
But Belgian and Dutch firms can’t offer their services in the U.S. Two pieces of legislation — the Foreign Dredge Act of 1906 and the Jones Act — effectively banned foreign companies from dredging in U.S. waters. All dredges must be U.S.-built, U.S.-operated and U.S.-crewed. Changes to the Jones Act in 1988 added yet another requirement: American ownership of all barges transporting dredged sand.
The purpose of restricting foreign dredges was to protect U.S. companies and spur the growth of the private dredge fleet, but it’s had the effect of creating a small, closed market that benefits a handful of U.S. operators while making coastal protection and restoration projects far more expensive.
The high cost of using dredged material has spurred the Coastal Protection and Restoration Authority to try a controversial experiment: building two Mississippi River sediment diversions in Plaquemines Parish. The diversions will allow the river to flow through gaps in the east and west bank levees, reaching coastal areas cut off from the river’s sediment-rich water. The hope is that the sediment will revive wetlands and build new land, offsetting the effects of sea level rise and boosting Louisiana’s natural storm defenses.
At a combined $2 billion, the diversions will be the most expensive restoration projects ever attempted in Louisiana. Shrimpers and oyster growers say the added fresh water and sediment will harm their industries, and some coastal communities worry about increased flood risk. But once built, the diversions will ease the state’s dependence on dredges, at least in the bays and inlets linked to the new river outlets.
It isn’t just Louisiana feeling the pinch. The U.S. Army Corps of Engineers, the biggest customer for dredges, says federal spending on navigation dredging — the work that clears rivers and harbors for shipping — has exploded, increasing by several hundred million dollars each year in recent decades.
As costs have risen, the volume of dredged material has fallen. Yet demand for dredging grows, both for restoration projects and for shipping ports that hope to draw the largest classes of “mega-cargo” freighters.
A captive market
The Corps used to meet nearly all its dredging needs with its own sizable fleet. During the 1970s, Congress began privatizing the Corps’ dredge work, first by cutting support for replacement vessels and then by ordering the Corps to rely on private dredgers.
The Corps’ fleet of 14 hopper dredges, highly sought-after vessels capable of both dredging and hauling material, has dwindled to just four, including the 53-year-old McFarland, a ship that probably should have been retired more than 15 years ago, according to a federal audit.
Privatizing the U.S. dredge fleet hasn’t increased the supply of ships or led to cost savings, however. About 98% of all private sector dredge work in the U.S. is handled by four firms — Great Lakes Dredge and Dock, of Illinois; Weeks Marine, of New Jersey; Manson Construction, of Washington state; and Dutra Dredging, of California.
Together, they accounted for $1.2 billion of the $1.3 billion the Corps spent on dredging between 2005 and 2015, according to the Center for Strategic and International Studies. In many cases, bidding for Corps projects draws interest from just one or two companies. Under single-bid scenarios, dredge companies typically charge two times as much as when four or more companies compete, a study by the center found.
Though American dredges come at a premium, they’re comparatively small, old and inefficient. A 2014 Government Accountability Office assessment found U.S. dredges averaged about 27 years in age. European vessels were much younger, with some companies boasting fleets with an average age of 10 years.
Only five U.S. companies have hopper dredges. Their combined capacity amounts to less than a third of what one Dutch firm, Rotterdam-based Van Oord, can offer, according to data from the Corps and international dredging organizations.
Van Oord has done “shadow estimates” of recent port deepenings and other large dredge projects in U.S. waters. Even if the company used mostly American crews and local support vessels, Van Oord estimates it could typically do the work three times faster and at 60% of the cost.
European dredgers have long lobbied to enter the U.S. market, estimating American taxpayers could save $1 billion per year if foreign firms were allowed to compete with U.S. companies. Dutch, Belgian and other European firms have a 90% share of the open global market, thanks to highly mobile long-distance vessels that can, for instance, quickly move from a land-building job in the Persian Gulf to routine dredging in the Panama Canal.
“Our largest dredge is three or four times larger than the largest in the U.S.,” said Mark Roelofs, Van Oord’s director of dredging for North and South America. “You need a big market size to have that, and the world is our market.”
But don’t expect to see Dutch-flagged dredges on the Louisiana coast anytime soon. The U.S. dredging industry has been vigilant in its defense of the Foreign Dredge and Jones acts. Van Oord and other Dutch companies have suggested special waivers allowing them to dredge U.S. ports considered critical for national security and fuel transport. They’ve also offered to crew their vessels with mostly U.S. workers and hire local tugboats, barges and other support vessels.
Last year, the Trump administration gave assurances that no such waivers or other concessions for foreign vessels would be considered.
“President (Donald) Trump had the Jones Act matters all under control from the get-go,” William Doyle, executive director of the Dredging Contractors of America, said in a statement. “Mr. Trump is all about jobs and national security — he’s never wavered on this.”
The Coastal Protection and Restoration Authority tries to steer clear of such international political questions. Although altering the Foreign Dredge and Jones acts would be “not an insignificant lift,” said Grandy, the agency's deputy director, “We work within the dredge community we have in the U.S. and Gulf Coast.”
But he acknowledged foreign dredgers would be a boon for Louisiana’s coast.
“From a restoration standpoint, it would obviously create more supply and give us more folks who could dredge for us,” he said.
Engine for export
If the U.S. isn’t interested in Dutch dredges, what about Dutch ideas? The Dutch are glad to share the Sand Motor’s success. Exporting knowledge in water management and coastal protection is big business in the Netherlands, generating about $9 billion per year and accounting for about 2% of total exports. The Sand Motor is a major selling point.
“We would like to export our knowledge because it’s unique for the whole world,” said van Gelder-Maas, the Sand Motor manager.
The United Kingdom recently completed what van Gelder-Maas calls the Sand Motor’s “baby brother” along an eroding beach beside a large gas terminal. More than a dozen similar projects could be undertaken on the English coast, according to Dutch engineers working on foreign projects.
If other countries aren’t trying to buy their own Sand Motors, they’re sending scientists to study how the project works. More than 75 Sand Motor studies by scientists from Australia, New Zealand, the Bahamas, the U.S. and elsewhere have been published in recent years.
“I was at a coastal sediment conference in Florida, and there were a lot of (Sand Motor) presentations,” van Gelder-Maas said. “Most were about how to do it on the East Coast and West Coast.”
Much interest from Louisiana?
“Actually, no,” she said.
Coastal Protection and Restoration Authority officials haven’t studied the Sand Motor, but its central idea of letting nature do the heavy lifting should be “applied to everything we build,” Grandy said.
Smaller versions of the Sand Motor might work on the Louisiana coast, possibly to rebuild the Caminada Headland or barrier islands, according to coastal authority officials.
“We might not go as ‘mega’ as the Netherlands, but it’s definitely possible to (try) the concept here,” Grandy said.
It was tried once in Louisiana during the early 1990s, but mostly as a way to get around wildlife protection rules. Unable to dump river sediment directly on pelican nesting habitat on Breton Island, the Corps instead poured it about 100 yards from shore. Waves pushed much of the sediment to the island as planned, “but it didn’t stick,” said Ed Creef, an environmental resources specialist who led the project for the Corps. “With waves and storms, it was a very rough environment. By 1999, it was all gone.”
Natural forces have made lasting improvements to restoration projects, but not by design. Sand from an old project moved to form the foundation of a new coastal authority project at Port Fourchon. The agency's engineers cite it as proof that “building with nature” can work on the Louisiana coast, but they can’t claim credit for it.
“It was more serendipitous,” Grandy admitted.
Grandy said the need to harness nature to help restore the coast is “a lesson we learned a long time ago.” It was highlighted in the state’s 2017 Coastal Master Plan and may be a component of an upcoming plan for future barrier island restoration projects, he said.
Yet the next batch of scheduled barrier island and headland restoration projects rely on what has become the coastal authority's standard approach. Work on Timbalier, Trinity and Grand Terre islands and the West Belle headland will use methods similar to the Whiskey Island and Caminada projects. And it will come at a high cost: $268 million.
In 15 or 20 years, all these projects, critical for the protection of Louisiana’s ports, coastal communities and vanishing wetlands, will need to be redone. Barring another catastrophic oil spill and the vast legal settlement that comes with it, state leaders will likely have no way to pay for it.
Until they somehow find hundreds of millions — perhaps billions — of dollars to fill the ever-widening funding gap, or else turn to cheaper, Sand Motor-inspired methods of rebuilding the coast, at least one state leader won’t be sleeping well.
“It does keep me up at night,” Grandy said. “There are very few things that keep me up, but that’s definitely on the short list.”
Jeff Adelson, of the Times-Picayune | New Orleans Advocate, and Tegan Wendland, of WWNO New Orleans Public Radio, contributed to this story.