Zandmotor vlucht-7 11-04-2011 foto: Rijkswaterstaat/Joop van Houdt
(Photo: Rijkswaterstaat/Joop van Houdt)

Necessity truly is the mother of invention. With almost three quarters of the Netherlands at or below sea level, Dutch engineers are finding new ways to protect themselves from the increasing threat of floods due to climate change by using nature as a defense against rising tides.
In a report for Yale Environment 360, Cheryl Katz explains:

“With sea levels climbing—many coastal experts are projecting rises of 3 to 5 feet this century—and climate change expected to boost storm frequency and intensity, flood protection is an increasingly pressing issue worldwide. And at the forefront of flood-control technology are the Dutch, long aware of the damage that surging oceans and overflowing rivers can wreak in their low-lying country. Hydraulic engineering has been underway here since the Middle Ages, and the country’s 16.7 million residents have ‘dry feet’ thanks to a network of dikes, canals, and engineering marvels like the Maeslant Barrier near Rotterdam: two floating gates, each the length of the Eiffel Tower, that automatically close to shield the city and its major port when a North Sea storm surge threatens.”


A most recent example of one of these types of “soft defenses” (so named because they circumvent the construction dikes and other hard structures), is the Sand Engine, a vast reservoir of sand continually cultivated to protect eroding beaches. “Completed in late 2011 at a cost of $67 million, the Sand Engine’s goal is to provide long-term fortification for eroding beaches as ocean currents gradually redistribute its dredged material,” writes Katz. “Until now, this coastline needed sand replenishment every five years, requiring expensive dredging that damaged marine ecosystems.” The Sand Engine, meanwhile, should last for 20 years.
Katz warns that soft defenses are not a panacea, noting that Dutch engineers are simultaneously employing other technologies, such as “Smart Dikes”—sensor-embedded levees that relay real-time information—to aid in decision-making.
And while soft defenses are not commonly used in the United States, which has favored emergency preparedness and recovery over taking a more preventative approach, Katz writes that when faced with the global challenge of climate change, “the objectives are now converging.”