Architecture Lab

Sponge Parks, Sand Dunes May Boost Resilience to Storms

Among the proposals by Susannah Drake of Dlandstudio and Stephen Cassell of Architecture Research Office was the “Sponge Slip,” which would have replaced a Lower Manhattan parking lot with a sunken park...

A couple of years ago, I walked along a flood-protection wall in the oceanfront New Jersey town of Sea Bright and wondered how severe weather would affect it. Now I know.
Photos show waves overtopping the wall and sweeping through the streets of the town, very close to where Hurricane Sandy made landfall on Oct. 29.

Sponge Parks, Sand Dunes May Boost Resilience to Storms

A view of structures demolished by Hurricane Sandy in Sea Bright, on Nov. 20, 2012. Along the Jersey ocean shoreline structures that were built on the beach without the protection of dunes or bulkheads sustained the worst damage. Better-protected structures may have flooded but many suffered little structural damage // Photo by James S. Russell/Bloomberg

Many cities and states have drawn up plans to increase resilience to catastrophes, but there has been little impetus to act on anything that’s costly or requires complex negotiations.

The obvious answer is to build higher sea walls along the ocean coast or around Lower Manhattan. In New York City there’s long been talk of a massive storm-surge barrier outside the Verrazano-Narrows Bridge. These are investments of at least hundreds of billions of dollars…

….Rebuilding natural dunes is a “soft” path to coastal restoration. The dunes repel waves and feed the beach with sand. Many shorefront owners will demand higher seawalls, which is the “hard” path, and it has drawbacks.

Engineered fortifications also destroy the beach ecology and the amenity that draws people and creates jobs. Seawalls can induce permanent loss of beach sand, requiring even higher walls. For that matter, dune building isn’t foolproof; dunes slowed Sandy’s surge but didn’t stop extensive flooding..

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