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

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.

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.

The dangers were magnified in 2005 when Hurricane Katrina breached flood walls and levees, submerging 80% of New Orleans and killing almost 1,400 people — followed closely by Hurricane Rita.

Afterward, the state formed the Coastal Protection and Restoration Authority to lessen risks from storm surges and stem land loss.

Most of the almost $18 billion spent in the past 20 years was to shore up levees, flood walls and other structures, the authority said.

Dozens of other projects are completed, planned or underway, including rebuilding marshes and other habitat with sediment dredged from waterways and restoring river flow to areas that have lacked it for years.

On Louisiana’s Chandeleur Islands, a barrier island chain, the state will pump in sand to help rebuild them, which will dampen storm surges and benefit sea turtles and other wildlife, said Katie Freer-Leonards, who leads development of the state’s 2029 coastal master plan.

The authority is digging a channel to allow water and sediment from the Mississippi River to flow into part of Maurepas Swamp, a roughly 218-square-mile forested wetland northwest of New Orleans that has been “dying for over a century” because of levees, project manager Brad Miller said.

Sediment dredged from elsewhere also has been pumped into thousands of acres of sinking marshes to nourish them and raise their levels.

The same is happening in other states.

In Bayou La Batre, Alabama — a fishing village built in the late 1700s — The Nature Conservancy built breakwaters offshore, then pumped in sediment and built ridges, now covered with vegetation. That created a “speed bump” that has helped protect the town from erosion, said Judy Haner, the Alabama Nature Conservancy’s coastal programs director.

The conservancy and others also have been creating miles of oyster reefs, and are acquiring tracts of land away from the coast to allow habitats to move as seawater encroaches.

Such efforts won't prevent all land losses, but in Louisiana, “cumulatively, they could make a big difference," said Denise Reed, a research scientist who is working on Louisiana's coastal master plan. “It could buy us some time.”

On the West Coast, communities vulnerable to sea-level rise also could see more flooding from increasingly intense atmospheric rivers, which carry water vapor from the ocean and dump huge amounts of rain in a short period of time.

So tidal marshes and estuaries drained for agriculture and industry are being restored along the entire coast, both for habitat and coastal protection.

Habitat restoration, not climate change, was the primary consideration when planning began about 20 years ago to restore marshland along the south end of San Francisco Bay, destroyed when ponds were created to harvest sea salt.

But as sediment naturally fills in ponds and marsh plants return, “we're realizing that ... marshes absorb wave energy, storm surge and the force of high tides,” said Dave Halsing, executive project manager at the California State Coastal Conservancy.

That helps protect whatever is behind them, including sea walls and land that otherwise could be inundated or washed away, including some of California's most expensive real estate, near Silicon Valley.

Projects also are underway along Alaska’s coast and in Hawaii, where native residents are rebuilding ancient rocky enclosures originally intended to trap fish, but which also protect against storm surge.

Thirteen years after Superstorm Sandy swamped the Atlantic coast, communities still are restoring natural buffers and building other protective structures.

Sandy began as a fairly routine hurricane in the fall of 2012 before merging with other storms, stretching for a record 1,000 miles and pushing enormous amounts of ocean water into coastal communities.

But the threat of future storm surges could be even greater because sea levels in some areas could rise as much as three feet within 50 years, said Donald E. Cresitello, a coastal engineer and senior coastal planner for the U.S. Army Corps of Engineers.

The Corps rebuilt beaches, dunes and human-made structures from Massachusetts to Virginia and now is turning to areas farther inland that are increasingly vulnerable to more powerful storm surges, Cresitello said.

“If there’s a river coming to the coast, that storm surge has the potential to just ride up that river," depending on the storm, he said.

A “phenomenal amount” of the U.S. population lives and works along its coasts, so protecting those areas is important to the U.S. economy, said George, the NOAA scientist. But it is also important to preserve generations of culture, he said.

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

Associated Press Video Journalist Stephen Smith contributed to this report.

The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.

Birds swim in Stevens Creek, which is located southeast of the Pond A2W site for the South Bay Salt Pond Restoration Project in Mountain View, Calif., Thursday, Aug. 7, 2025. (AP Photo/Godofredo A. Vásquez)

Pond A19, which has been fully restored as part of the South Bay Salt Pond Restoration Project, is visible Thursday, Aug. 14, 2025, in Fremont, Calif. (AP Photo/Godofredo A. Vásquez)

A black-necked stilt is seen at Don Edwards San Francisco Bay National Wildlife Refuge, Thursday, Aug. 14, 2025, in San Jose, Calif. (AP Photo/Godofredo A. Vásquez)

Vegetation is seen at the bottom of Ravenswood Pond R4, which was breached in December 2023 as part of the South Bay Salt Pond Restoration Project, during low tide Thursday, Aug. 14, 2025, in Menlo Park, Calif. (AP Photo/Godofredo A. Vásquez)

The Pond A1 site, center, for the South Bay Salt Pond Restoration Project is photographed Thursday, Aug. 7, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

Crew members work on a wildlife exclusion fence at the Pond A2W site of the South Bay Salt Pond Restoration Project in Mountain View, Calif., Thursday, July 24, 2025. (AP Photo/Godofredo A. Vásquez)

People walk on a trail next to Pond A1 in Mountain View, Calif., Thursday, July 24, 2025. (AP Photo/Godofredo A. Vásquez)

A cyclist travels on a trail along the the Pond A1 site for the South Bay Salt Pond Restoration Project, Thursday, Aug. 7, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

The Pond A2W site for the South Bay Salt Pond Restoration Project is photographed Thursday, Aug. 7, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

Dave Halsing, executive project manager at the California State Coastal Conservancy, looks at the Pond A1 site Thursday, July 24, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

Crew members install sound blankets to protect wildlife at the Pond A2W site of the South Bay Salt Pond Restoration Project, Thursday, July 24, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

A man runs on a trail at Bedwell Bayfront Park as the Ravenswood Pond R4 is seen in the background, Thursday, Aug. 14, 2025, in Menlo Park, Calif. The pond is part of the South Bay Salt Pond Restoration Project. (AP Photo/Godofredo A. Vásquez)

Crew members work on the Pond A2W site of the South Bay Salt Pond Restoration Project, Thursday, July 24, 2025, in Mountain View, Calif. (AP Photo/Godofredo A. Vásquez)

ATLANTA (AP) — Donald Trump would not be the first president to invoke the Insurrection Act, as he has threatened, so that he can send U.S. military forces to Minnesota.

But he'd be the only commander in chief to use the 19th-century law to send troops to quell protests that started because of federal officers the president already has sent to the area — one of whom shot and killed a U.S. citizen.

The law, which allows presidents to use the military domestically, has been invoked on more than two dozen occasions — but rarely since the 20th Century's Civil Rights Movement.

Federal forces typically are called to quell widespread violence that has broken out on the local level — before Washington's involvement and when local authorities ask for help. When presidents acted without local requests, it was usually to enforce the rights of individuals who were being threatened or not protected by state and local governments. A third scenario is an outright insurrection — like the Confederacy during the Civil War.

Experts in constitutional and military law say none of that clearly applies in Minneapolis.

“This would be a flagrant abuse of the Insurrection Act in a way that we've never seen,” said Joseph Nunn, an attorney at the Brennan Center for Justice's Liberty and National Security Program. “None of the criteria have been met.”

William Banks, a Syracuse University professor emeritus who has written extensively on the domestic use of the military, said the situation is “a historical outlier” because the violence Trump wants to end “is being created by the federal civilian officers” he sent there.

But he also cautioned Minnesota officials would have “a tough argument to win” in court, because the judiciary is hesitant to challenge “because the courts are typically going to defer to the president” on his military decisions.

Here is a look at the law, how it's been used and comparisons to Minneapolis.

George Washington signed the first version in 1792, authorizing him to mobilize state militias — National Guard forerunners — when “laws of the United States shall be opposed, or the execution thereof obstructed.”

He and John Adams used it to quash citizen uprisings against taxes, including liquor levies and property taxes that were deemed essential to the young republic's survival.

Congress expanded the law in 1807, restating presidential authority to counter “insurrection or obstruction” of laws. Nunn said the early statutes recognized a fundamental “Anglo-American tradition against military intervention in civilian affairs” except “as a tool of last resort.”

The president argues Minnesota officials and citizens are impeding U.S. law by protesting his agenda and the presence of U.S. Immigration and Customs Enforcement officers and Customs and Border Protection officers. Yet early statutes also defined circumstances for the law as unrest “too powerful to be suppressed by the ordinary course” of law enforcement.

There are between 2,000 and 3,000 federal authorities in the Minneapolis-St. Paul metro area, compared to Minneapolis, which has fewer than 600 police officers. Protesters' and bystanders' video, meanwhile, has shown violence initiated by federal officers, with the interactions growing more frequent since Renee Good was shot three times and killed.

“ICE has the legal authority to enforce federal immigration laws,” Nunn said. “But what they're doing is a sort of lawless, violent behavior” that goes beyond their legal function and “foments the situation” Trump wants to suppress.

“They can't intentionally create a crisis, then turn around to do a crackdown,” he said, adding that the Constitutional requirement for a president to “faithfully execute the laws” means Trump must wield his power, on immigration and the Insurrection Act, “in good faith.”

Courts have blocked some of Trump's efforts to deploy the National Guard, but he'd argue with the Insurrection Act that he does not need a state's permission to send troops.

That traces to President Abraham Lincoln, who held in 1861 that Southern states could not legitimately secede. So, he convinced Congress to give him express power to deploy U.S. troops, without asking, into Confederate states he contended were still in the Union. Quite literally, Lincoln used the act as a legal basis to fight the Civil War.

Nunn said situations beyond such a clear insurrection as the Confederacy still require a local request or another trigger that Congress added after the Civil War: protecting individual rights. Ulysses S. Grant used that provision to send troops to counter the Ku Klux Klan and other white supremacists who ignored the 14th and 15th amendments and civil rights statutes.

During post-war industrialization, violence erupted around strikes and expanding immigration — and governors sought help.

President Rutherford B. Hayes granted state requests during the Great Railroad Strike of 1877 after striking workers, state forces and local police clashed, leading to dozens of deaths. Grover Cleveland granted a Washington state governor's request — at that time it was a U.S. territory — to help protect Chinese citizens who were being attacked by white rioters. President Woodrow Wilson sent troops to Colorado in 1914 amid a coal strike after workers were killed.

Federal troops helped diffuse each situation.

Banks stressed that the law then and now presumes that federal resources are needed only when state and local authorities are overwhelmed — and Minnesota leaders say their cities would be stable and safe if Trump's feds left.

As Grant had done, mid-20th century presidents used the act to counter white supremacists.

Franklin Roosevelt dispatched 6,000 troops to Detroit — more than double the U.S. forces in Minneapolis — after race riots that started with whites attacking Black residents. State officials asked for FDR's aid after riots escalated, in part, Nunn said, because white local law enforcement joined in violence against Black residents. Federal troops calmed the city after dozens of deaths, including 17 Black residents killed by local police.

Once the Civil Rights Movement began, presidents sent authorities to Southern states without requests or permission, because local authorities defied U.S. civil rights law and fomented violence themselves.

Dwight Eisenhower enforced integration at Central High School in Little Rock, Arkansas; John F. Kennedy sent troops to the University of Mississippi after riots over James Meredith's admission and then pre-emptively to ensure no violence upon George Wallace's “Stand in the Schoolhouse Door” to protest the University of Alabama's integration.

“There could have been significant loss of life from the rioters” in Mississippi, Nunn said.

Lyndon Johnson protected the 1965 Voting Rights March from Selma to Montgomery after Wallace's troopers attacked marchers' on their first peaceful attempt.

Johnson also sent troops to multiple U.S. cities in 1967 and 1968 after clashes between residents and police escalated. The same thing happened in Los Angeles in 1992, the last time the Insurrection Act was invoked.

Riots erupted after a jury failed to convict four white police officers of excessive use of force despite video showing them beating a Rodney King, a Black man. California Gov. Pete Wilson asked President George H.W. Bush for support.

Bush authorized about 4,000 troops — but after he had publicly expressed displeasure over the trial verdict. He promised to “restore order” yet directed the Justice Department to open a civil rights investigation, and two of the L.A. officers were later convicted in federal court.

President Donald Trump answers questions after signing a bill that returns whole milk to school cafeterias across the country, in the Oval Office of the White House, Wednesday, Jan. 14, 2026, in Washington. (AP Photo/Alex Brandon)