Fifty years after digging the Mississippi River-Gulf Outlet shipping passage and destroying vast wetland areas, the Army Corps of Engineers has begun to look at restoring the damage the channel caused in the swampy landscape southeast of New Orleans.

The agency announced Thursday plans to conduct public hearings and compile a report on what measures can be taken to restore those wetlands.

“The Corps will evaluate a full range of comprehensive restoration measures to restore important estuarine components and ecosystem processes within the areas affected by the MRGO navigation channel,” the agency said.

For decades, residents and environmentalists have railed against the shipping channel as they watched it grow in size due to erosion, bringing with it daily tidal flows of salt water that killed marsh and swamp forests.

After Hurricane Katrina, the outcry against the channel gained momentum, prompting Congress to allow the corps to close the shipping route. The corps plans to hire contractors to plug the channel by June 2009 with rocks.

The route was originally dug in the late 1950s as a shortcut between the Gulf of Mexico and New Orleans. But it never took off and was not widely used by ship traffic. In part, that was because ships have to pass through locks to reach the main port on the Mississippi River when they take the MRGO.

Despite the lack of use and wetlands destruction, the channel remained open until Katrina.

After the storm, scientists and residents blamed the MRGO for flooding in eastern portions of the metropolitan area. A lawsuit over that allegation is pending and the corps faces paying residents tens of millions of dollars in damages.

“For 40 years, it’s been a cancer eating up the coast,” said Carlton Dufrechou, executive director of the Lake Pontchartrain Basin Foundation, a group advocating the restoration of the lake system surrounding New Orleans.

“The plug and the restoration of the MRGO are the most critical projects for southeast Louisiana,” he said. “There is nothing that has a higher priority.”

The plug — closing the MRGO with rocks — may be close at hand, but restoration has a long way to go.

The corps says it plans to finish the first step of drawing up a draft environmental impact report by March 2010. After that, the corps would have to do more environmental and engineering studies to determine what steps to take. Then, Congress would need to approve the eventual restoration plan.

Congress asked the corps to close the MRGO and come up with a restoration plan last year. The work is to be paid entirely by the federal government.

To restore the ecosystem around the MRGO, the corps is looking at building water-control structures like gates, weirs and sills, stopping salt water from coming inland, diverting new sediment into the area, planting marshes and restoring natural ridges.

The corps’ decisions will be driven by cost and environmental considerations, the agency said.

Public meetings will be held throughout the process, the agency said. The first meeting is scheduled for Nov. 3 in Chalmette.