A new research project from MIT can help save small islands and coastal towns threatened by rising sea levels around the world.
Under the leadership of MIT researcher Skylar Tibbits, the project uses ocean waves to move sand over land and can be used to supplement the total landmass of risk islands or coastal cities.
In early testing, the technology added more than five feet to the shoreline of a small island in the Maldives, moving the equivalent of 10,600 cubic feet of sand to shore in four months.
MIT researchers traveled to the Maldives to test a new device that will help rebuild coastlines by rerouting ocean waves and pushing sand to shore
“By working with the natural forces of the ocean, we think we can promote the self-organization of sand structures to grow islands and rebuild beaches,” Tibbits said in an interview with MIT News.
“We believe this is a sustainable approach to the problem that can ultimately scale up to many coastal areas around the world, just as forest management is used to help strengthen and protect forests from uncontrolled fires or overgrowth.”
The project is built around submersible pumps filled with air or sand, which are then installed in strategic locations on the ocean floor.
The blisters act as natural slopes that lift ocean waves higher than they otherwise would, and when the waves crash down the other side of the slope, the force pushes sand from the ocean floor slightly further up the coast.
Tibbits started working on the project after being invited to the Maldives by Invena, a technology and investment group looking for ways to help low-lying island states protect themselves from rising sea levels.
The devices are large submersible bladders installed on the ocean floor that cancel out ocean waves as they pass. When the waves on the other side fall back down, the force creates a large divot that gradually pushes the sand towards the shore
In early tests, the MIT team found that the bladders added more than five feet of shoreline over a four-month period and moved about 10,600 cubic feet of sand
According to the group, about 40 percent of the world’s population lives in coastal areas or island countries threatened by rising sea levels.
Some previous efforts have focused on dredging sand from the ocean floor with industrial machinery and moving to land, but the team was skeptical about the long-term viability of this method.
“We began to realize that the amount of energy, time, money, labor and destruction of the marine environment caused by dredging could probably be stopped if we understand why sandbanks naturally arise and take advantage of this natural phenomenon of self-organization, ‘said Tibbits.
MIT’s Skylar Tibbits came up with the idea for the submersible bladders after seeing how reefs and shifting ocean currents at different times of the year can help build sandbars in the ocean
The team has developed a number of different types of bladder, including sand-filled and air-filled, which can be placed at different depths to adapt to changing weather or ocean currents
Tibbits believes the devices could be an environmentally friendly alternative to dredging activities currently used by some countries to strengthen their coastlines, using heavy machinery to extract sand and transport sand from the ocean floor
Tibbits chose the idea of the slope after the team noticed how often small sandbars formed and then disappeared again based on the interplay of reefs and small rock formations with the changing ocean currents.
“In many ways, they behave like natural depth variations, reef structures or volcanic formations and can act in the same way to promote sand build-up,” Tibbits explained.
“Our goal is to create customizable versions of these geometries that can be easily moved, reoriented or deployed as the seasons change or storms increase.”
The MIT team was initially invited to the Maldives by Invena, an investment and technology company looking for ways to help island states and coastal areas threatened by rising sea levels
So far, the MIT group has conducted four field tests of their blower equipment and will conduct two more field tests later in 2020 and early 2021
So far, the team has conducted four field tests and two more are planned for later this year and early 2021.
The long-term goal is to create a system that can be easily moved or adapted to the seasons or take advantage of the weather conditions to achieve the maximum benefit to the shoreline.
“We want to scale and tailor this approach to many locations around the world to help rebuild and stabilize densely populated coasts and fragile island states,” Tibbits said.