Coastal communities restoring marshes, dunes, reefs to protect against rising seas

In the Bay of San Francisco, the ponds of salt created over a century ago returned to the marshes. Along the Côtes de New York and New Jersey, the beaches ravaged by Superstorm Sandy suffered a large restoration. In Alabama, a reconstructed land spindle protects a historic city and provides a wildlife habitat.

The country’s coastal communities increase efforts to push the rise of seas, highest tides and stronger storm waves that chew the ribs, pushing the salt water more inside the land and threatening ecosystems and communities.

The need for coastal catering was under the spotlight this month after Louisiana officials canceled a $ 3 billion project due to objections of the fishing industry and concerns about the rise in costs. The Mid-Barataria project was to rebuild more than 20 square miles (32 square kilometers) of land over about 50 years by diverting the water loaded with Mississippi sediments.

But the work continues on many other projects in Louisiana and throughout the country, notably the barriers, the marshes of salt water, the reefs of crustaceans and other natural characteristics which offered protection before being destroyed or degraded by development. Communities also build walls, bearms and dikes to protect areas that lack adequate natural protection.

The work has become more urgent because climate change causes more intense and destructive storms and leads to an increase in sea level which puts hundreds of communities and tens of millions of people in danger, according to scientists.

“The sooner we can make these coasts more resilient, the better,” said Doug George, an oceanographer with the National Oceanic and Atmospheric Administration.

In the United States, perhaps nowhere is no vulnerable than the Gulf coast subject to hurricanes. Louisiana alone has lost more than 2,000 square miles (5,180 square kilometers) by coast – more than any other state – during the last century, according to US Geological Survey.

Historically, the sediments deposited by the Mississippi and other rivers have rebuilt the land and marshes to compress from the fed shore. But this function was disrupted by the construction of channels and dikes, as well as other development.

The dangers were amplified in 2005 when Hurricane Katrina violated the walls and dikes, overwhelming 80% of New Orleans and killing nearly 1,400 people – followed closely by Hurricane Rita.

Subsequently, the State formed the coastal protective and catering authority to reduce the risks of storm overvoltages and the loss of grounds of the stem.

Most of the nearly $ 18 billion spent in the past 20 years have been to consolidate the dikes, flood walls and other structures, the authority said.

Dozens of other projects are completed, planned or underway, including the reconstruction of marshes and other habitats with sediments of the sailor -saves and restore the flow of the river to the areas that have been missing for years.

On the islands Chandeleur de la Louisiana, a chain of the barrier island, the state will pump in the sand to help rebuild them, which will attenuate the storm waves and will benefit sea turtles and other wild animals, said Katie Freer-Leonards, who directs the development of the State Coastal Plan in 2029.

Authority is digging a channel to allow water and sediment of the Mississippi river to flow into a part of Maurepas Swamp, a wooded wetland of around 218 miles square in the northwest of New Orleans which “died for more than a century” because of the levees, said Brad Miller, director of the project.

The sediments dredged, moreover, were also pumped into thousands of acres of shipwreck to feed them and increase their levels.

The same thing happens in other states.

In Bayou La Batre, Alabama – A fishing village built in the late 1700s – the Conservancy nature built offshore breeze, then pumped in sediments and built, now covered with vegetation. This created a “slowdown” which helped protect the city from erosion, said Judy Haner, director of coastal programs at Alabama Nature Conservancy.

The Conservancy and others have also created miles of oyster reefs and acquire land areas far from the coast to allow habitats to move while seawater encroaches.

Such efforts will not prevent all land losses, but in Louisiana, “cumulatively, they could make a big difference,” said Denise Reed, a researcher who works on the coastal director of Louisiana. “It could buy us time.”

On the west coast, communities vulnerable to sea level elevation could also see more floods from increasingly intense atmospheric rivers, which transport a water vapor from the ocean and pour huge amounts of rain in short time.

The tidal swamps and the estuaries drained for agriculture and industry are restored throughout the coast, both for housing and coastal protection.

The restoration of the habitat, and not climate change, was the main consideration when planning began about 20 years ago to restore the marshes along the southern end of the Bay of San Francisco, destroyed when ponds were created to harvest sea salt.

But as the sediments naturally fill the ponds and marsh plants, “we realize that … the marshes absorb the energy of the waves, the storm wave and the strength of the tides,” said Dave Halsing, executive project manager of California State Coastal Conservancy.

This helps protect everything behind them, including the maritime walls and land that could otherwise be flooded or carried away, including some of the most expensive real estate in California, near Silicon Valley.

Projects are also underway along the coast of Alaska and Hawaii, where native residents rebuild old rocky enclosures originally intended to trap fish, but which also protect against storm waves.

Thirteen years after the Superstorm submerged the Atlantic coast, communities still restore natural stamps and build other protective structures.

Sandy started as a fairly routine hurricane in the fall of 2012 before merging with other storms, extending for a record of 1,000 miles and pushing huge quantities of ocean water in coastal communities.

But the threat of future storm waves could be even greater because the sea level in some regions could increase up to three feet in 50 years, said Donald E. Creatitello, coastal engineer and the main coastal planner of the body of American army engineers.

The body has rebuilt the beaches, dunes and structures made by man from Massachusetts to Virginia and now turns to more inland areas which are increasingly vulnerable to more powerful storm waves, said Creatitello.

“If there is a river coming to the coast, this storm wave has the potential to simply set up this river,” he said.

A “phenomenal quantity” of the American population lives and works along its coasts, so the protection of these areas is important for the American economy, said George, the Noaa scientist. But it is also important to preserve generations of culture, he said.

“When you think about the reason why people should care about it … It’s a whole way of life,” said George.

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Associated Press video journalist Stephen Smith has contributed to this report.

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