In San Francisco Bay, salt ponds created more than a century ago are reverting to marshland. Along the New York and New Jersey coasts, beaches ravaged by Superstorm Sandy underwent extensive restoration. In Alabama, a rebuilt spit of land is shielding a historic town and providing wildlife habitat.
Coastal communities nationwide are ramping up efforts to fend off rising seas, higher tides and stronger storm surges that are chewing away at coastlines, pushing saltwater farther inland and threatening ecosystems and communities.
The need for coastal restoration has been in the spotlight this month after Louisiana officials canceled a $3 billion project because of objections from the fishing industry and concerns about rising costs. The Mid-Barataria project was projected to rebuild more than 20 square miles (32 square kilometers) of land over about 50 years by diverting sediment-laden water from the Mississippi River.
But work continues on many other projects in Louisiana and around the country, including barrier islands, saltwater marshes, shellfish reefs and other natural features that provided protection before they were destroyed or degraded by development. Communities are also building flood walls, berms and levees to protect areas that lack adequate natural protection.
The work has become more urgent as climate change causes more intense and destructive storms and leads to sea-level rise that puts hundreds of communities and tens of millions of people at risk, scientists say.
“The sooner we can make these coastlines more resilient the better,” said Doug George, a geological oceanographer at the National Oceanic and Atmospheric Administration.
Gulf Coast
In the U.S., perhaps nowhere is more vulnerable than the hurricane-prone Gulf Coast. Louisiana alone has lost more than 2,000 square miles (5,180 square kilometers) of coastline — more than any other state — over the past century, according to the U.S. Geological Survey.
Historically, sediment deposited by the Mississippi and other rivers rebuilt land and nourished shore-buffering marshes. But that function was disrupted by the construction of channels and levees, along with other development.