Monday, July 22, 2019

How engineers are preparing for rising sea-levels

Piloting his crab boat during a storm off Tangier Island, Va., Mayor James Eskridge sweeps his hand over the water and says, “I remember when all of this area was land.”

Below the water are the homes, stores and graves of the Tangier Island communities that have been swallowed by the sea. Since 1850, the island has lost more than 66% of its land mass. Today, the 1.2-sq-mile island continues to erode by as much as 25 ft per year.

“There are other communities around here that have disappeared,” he says. “We’ve seen what can happen to us if we don’t get the help we need.”

Eskridge says his island is eroding but thinks sea-level rise has little to do with it. Scientists, however, say erosion, saltwater intrusion, storm surges and king tides—an exceptionally high but predictable tide that does not result from a storm event but from an alignment of the moon, the earth and the sun—experienced in Tangier and elsewhere are being made worse by the rising sea level, and the problems will accelerate in the near future. The National Oceanic and Atmospheric Administration says nuisance flooding has increased in the U.S. between 300% to 900% from 50 years ago.

In this special report, Engineering News-Record’s team of editors and reporters look at how Tangier and other coastal communities around the country are tackling problems, including erosion, subsidence and sea-level rise. Our reporting has found that many cities are still trying to get a handle on the complex, interrelated problems. But others, such as Miami Beach, have started aggressive, multimillion-dollar programs to raise roads and improve drainage.

We also found that engineers are rethinking their practice, coming up with innovative, adaptive designs that will prevent overbuilding in the short term until future forecasts—which now say the sea level could rise between 1 ft to 8.2 ft by 2100—become more precise.

Continue reading in Engineering News-Record

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