Sisyphus on the beach: Dorian stresses the incessant task of rebuilding coastal cities

JACKSONVILLE BEACH, Florida (Reuters) – Just months after the US Army Corps of Engineers completed a $ 16 million project to restore sandy beaches in Jacksonville, Florida, the hurricane Dorian is about to hit them again, illustrating the tough battle that US coastal cities are facing in protecting their most valuable asset.

According to the US Geological Survey, the hurricane, which has already devastated the Bahamas and caused at least five deaths in the Bahamas, is expected to cause the erosion of approximately 80% of the sandy beaches located between the Florida and North Carolina.

This figure is similar to the forecast for other past hurricanes in the region and some of this erosion will be temporary: the sand swept off by a storm is slowly returned to the beach the following weeks in good weather.

But dunes, often the last buffer between the ocean and coastal buildings and infrastructure, can take months or years to recover naturally from the damage done.

"It's a natural process, but with a hurricane, it obviously speeds up," said 48-year-old owner of a 48-year-old shipbuilding company, Richard Powell, in an interview in Jacksonville Beach, Florida. His company is building a pier on the beach and he admired the recent work of the Army Army Corps of Engineers: "It's a shame because the dunes have never been so beautiful."

Sandy beaches are a prime tourist attraction in Florida. The surrounding lands have become increasingly useful and developed over the last century, requiring considerable effort to prevent the shoreline from changing too much due to the natural erosion caused by storms and the rising level of rainfall. the sea caused by climate change.

Most of this work has been done by the Army Corps, which has been conducting "beach feeding" projects since the 1950s. adding tons of extra sand to the beaches, increasing the protection zone for the land behind.

The project recently completed by the Army Corps around Jacksonville included the restoration of the dunes damaged by Hurricane Matthew in 2016 and by Irma a year later.

Like all projects of this type, it is designed to be eroded during a storm, dissipate the energy of a storm and protect the city behind. The Corps says that project costs are largely outweighed by the potential costs of damage that they prevent from occurring.

Nevertheless, the renewal of the beach is a step by step effort. The Florida Department of Environmental Protection said nearly half of its beaches, about 640 km (400 miles), were badly eroded.

"There is not much to do before such a storm," said Kara Doran, a scientist at the US Coastal Geological Survey Center in St. Petersburg, Florida, in a phone interview. Dorian's enormous size and slow progress towards the American continent only aggravate the problem, she said, with damaging storm surges eroding the beaches for days.

According to the USGS, Dorian could send water on a quarter of the Florida dunes and nearly 60% of the dunes of Georgia and South Carolina. "The dunes, once eroded, take decades to rebuild," Doran said.

Chris Condon, 51, has lived in Jacksonville Beach for seven years and says previous hurricanes have taught him that one of the priorities is to "consolidate the dunes.

"They are building the dunes," he said, "closing the entrances and making sure there are no significant bridles so that the water can flow through and penetrate in the neighborhoods ".