Researchers hope to rescue California coast by zapping sand with electricity

SAN FRANCISCO -- A team of researchers is hoping it can future-proof the California coastline against erosion by zapping the sand with electricity.

The California coastline is eroding at a pace that some experts fear could accelerate as sea levels rise in the face of climate change.

"We're talking about anywhere between about a foot of sea level rise to somewhere closer to two, three feet or even more by the end of the 21st century. And, you know, just ballpark estimates, what that means in terms of mean shoreline change rates, you know, we're talking between somewhere in the ballpark of, you know, 40 to 50 feet for the low ends upwards of well over 100 to 150 feet for the higher ends," said Oregon State professor Peter Ruggiero, Ph.D.

For decades construction crews have fought to shore up beaches and cliffsides, saving homes, and in some cases entire neighborhoods, with technologies ranging from cement to rocky sea walls. But now, a research team from Northwestern University believes it may have another solution: essentially gluing the sand into place by zapping it with electricity.

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"In a nutshell, these work allows us to cement sand by using electrical energy," said Professor Alessandro Rotta Loria, Ph.D.

To understand the process, he says we should look to clams and mussels -- creatures that use their metabolism to transform elements like the calcium found in sea water into hardened shells. He says those same chemical building blocks exist in abundance along the coast, waiting to be transformed.

"By using electricity, we can actually convert these minerals, which are dissolved inside water into solid forms. So, we can basically transform them into solids, and we can transform it into cementing agents. So basically, we are really using the natural ingredients of seawater to cement soils," Rotta Loria said.

In controlled experiments, researchers used mild electrical currents to solidify sandy material into a rock-like substance. Rotta Loria believes the hardened sand could be cheaper and more efficient in holding off coastal erosion than current engineering methods. And, he says the team has concepts for a mesh-like delivery system that could electrify and harden even larger coastal areas.

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"They are highly scalable, because as a matter of fact, you can engineer that with a given size, and then you can just copy and paste and deploy it over very wide surfaces," Rotta Loria said.

And you can potentially use the technique in combination with other engineering solutions.

"Bolster some sand dunes or some sea cliffs backing some coastline and serve similar purposes that some of the great engineering examples do, but for maybe a lower cost," Ruggiero said.

Many researchers believe a combination of techniques will be needed just to buy time, including perhaps shoring up the coast by literally hardening sand. Regarding environmental concerns, the Northwestern team believes the low-level electricity would not be a threat to marine life. And they say the process is actually reversible.