Countries Are Building Giant ‘Sand Motors’ to Protect Their Coasts From Erosion

This story initially appeared on Grist and is part of the Climate Desk collaboration.

When governments uncover themselves combating the specter of coastal erosion, their default response tends to be pretty simple: If sand is disappearing from a seashore, they pump in extra sand to alternate it. This system, known as “seashore nourishment,” has flip right into a cornerstone of coastal defenses world vast, complementing laborious constructions like sea partitions. North Carolina, for instance, has dumped larger than 100 million tons of sand onto its seashores over the earlier 30 years, at a worth of larger than $1 billion.

The difficulty with seashore nourishment is clear. In case you dump sand on an eroding seashore, it’s solely a matter of time sooner than that new sand erodes. Then you will need to do it but once more.

Seashore nourishment duties are imagined to remaining for spherical 5 years, nonetheless they normally disappear faster than anticipated. Moreover, an enormous coastal storm can wipe them out in a single night. And the costs are staggering: Dragging in new sand requires leasing and dealing large diesel dredge boats. Solely the wealthiest areas can afford to do it yr after yr.

Now, after a few years of reliance on repeated seashore nourishment, a model new approach for managing erosion is displaying up on coastlines world vast. It’s often called the “sand motor,” and it comes from the Netherlands, a low-lying nation with centuries of experience in coastal security.

A “sand motor” isn’t an exact motor—it’s a sculpted panorama that works with nature fairly than in the direction of it. In its place of rebuilding a seashore with a superb line of newest sand, engineers lengthen one a part of the shoreline out into the ocean at an angle.. Over time, the pure wave movement of the ocean acts as a “motor” that pushes the sand from this protruding landmass out alongside the rest of the pure shoreline, spreading it down the shoreline for miles.

Whereas sand motors require much more upfront funding than common seashore nourishment—and loads of situations additional sand—moreover they protect additional land and remaining for for much longer. Developed nations such as a result of the Netherlands and the UK are turning to these megaprojects as another option to repeated nourishment, and the World Monetary establishment is financing a sand motor in West Africa as part of a billion-dollar adaptation program meant to fight sea-level rise. Nonetheless these massive duties solely work in areas the place erosion is simply not however at a important stage. Which suggests they’re unlikely to level out up within the USA, the place many coastal areas are already on the aim of disappearing altogether.

The idea for the problem acquired right here from a Dutch professor named Marcel Stive, who had watched with frustration as his nation’s authorities spent billions to nourish the equivalent coastal areas time and again as sea ranges saved rising. Stive supplied the thought to the federal authorities, which employed a giant dredging agency often called Boskalis to assemble a prototype on the shoreline south of The Hague.

Even this experimental problem, which the Dutch title “de Zandmotor,” was an unprecedented endeavor. Boskalis dredged up spherical 28 million cubic yards of sand from the ocean floor—larger than the Netherlands makes use of on nourishment duties nationwide in a given yr. Engineers then sculpted the sand proper right into a hook that curved eastward along the shore, guaranteeing that waves would push the sand northeast in the direction of seashores near The Hague. Moreover they created a lagoon in the midst of the sand building so that locals wouldn’t should stroll for almost a mile to get to the water. Throughout the years since Boskalis accomplished constructing on the $50 million problem, the hook of sand has flattened out, almost the easiest way a wave breaks as a result of it reaches the shore.