SIDEBAR-On the Dutch coast, an experiment in sand

by Reuters
Friday, 12 December 2014 14:22 GMT

(This story accompanies a Special Report, "Flirting with retreat along Britain's battered shore")

By Alister Doyle

TER HEIJDE, Netherlands, Dec 12 (Reuters) - A pile of sand about eight times the volume of the Great Pyramid of Giza is shaping up as a cut-rate model for protecting coasts from rising seas.

The "Sand Engine" is 28 million cubic yards (21.5 million cubic meters) covering an area 1.2 miles (2 km) long and half a mile wide. Dumped along the shore here in 2011, the sand pile marks a shift from the Dutch tradition of armoring the coast with dikes and other hardware.

Instead, the hope is that as all that sand is slowly blown and washed along the coast, it will feed nearby beaches and dunes for 20 to 30 years, providing the low-lying coast with long-term protection from erosion. That would make unnecessary a ritual of dredging the shore and replenishing the beaches every few years.

The project isn't without risks. A string of storms shifted more sand than expected, and if the sand travels too far, it could choke ports on the coast.

But so far, the 70 million euro ($95.48 million) Sand Engine "is doing more or less what was predicted, moving a bit faster than we thought," Jasper Fiselier, an environmental planner at engineering consultants Royal HaskoningDHV, said during a recent inspection. His company was one of several involved in the project, funded by the Dutch water board, Rijkswaterstaat, and the provincial authority of South Holland.

One way in which the project saved money: a bulk discount. The sand cost 2.5 euros ($3.40) per cubic meter, far less than the usual three to six euros per cubic meter, Fiselier said. The sand was supplied from the seabed by Dutch dredging specialists experts Royal Boskalis Westminster and Van Oord.

The Sand Engine has also become a recreation spot. About 20 kite surfers were in a lagoon formed by the hook-shaped sandy peninsula one day last summer, many of them beginners flailing with yellow, green or red sails in a stiff breeze.

Elsewhere, a group of Dutch farmers is deliberately pouring saltwater onto crops. In plots on Texel Island, where brackish water is seeping under dikes and onto farmland, they hope to breed varieties of potatoes, carrots, grass or barley that can resist salt.

"For farmers, talking about salinity is about as popular as talking about an infectious disease in your family," said Marc van Rijsselberghe, head of SaltFarmTexel, set up in 2006.

Twenty-six percent of the Netherlands lies below sea level, and seawater is seeping under dikes in many regions. "Sea level rise  adds pressure on the outside of the dikes," said Arjen de Vos, a scientist at VU University Amsterdam, a sponsor of the experimental farm. "There are many places on Texel where the water in drainage canals is really salty - cows can no longer drink it," he said.

The project could ultimately yield results that help farmers around the world who are dealing with salinity from rising sea levels, from Bangladesh to tiny Pacific islands, he said.

King Willem-Alexander visited the salt crop project in May, lending it implicit royal endorsement. "We've changed from being revolutionaries to being innovators," de Vos said of the visit.

SaltFarmTexel includes rows of potatoes, barley, carrots, onions and cabbage irrigated with varying levels of saltwater. The project has a few clients, ranging from farmers to golf course owners who test grasses suited to salty soils. They typically pay 15,000 euros for a small plot experimenting with different crop varieties and salt concentrations. (Edited by John Blanton)

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