It's a long shot in a slow process, contingent on a mire of competing interests and sloggish regulatory hurdles. But residents of Minneapolis' Longfellow neighborhood entertained, for a few hours Thursday night, the once-in-a-generation possibility of getting rid of the dams pacifying the Mississippi Gorge and letting the river run wild as it did before humans started messing with its flow.

This adventurous idea germinated with the closing of the Upper St. Anthony Lock in 2015, by order of Congress, to prevent the spread of invasive Bighead Carp. Closing one lock has since reduced traffic at two others nearby -- Lower St. Anthony Lock and Lock and Dam No. 1 -- by about half. As a result, the U.S. Army Corps of Engineers, which oversees all three sites, started thinking that it might not be worth the cost of keeping the locks and dams up.

The Corps has until August 16 to decide whether to stay or go. If they decide to slap a going-out-of-business sign on the sites, they'll proceed with study on how to get rid of them, which would take about two years.

At that point, the Corps would look at new owners, according to a strict chronology. Housing and Urban Development gets first dibs, said Corps project manager Nan Bischoff, om case they wanted to house the homeless there, though that's not likely. Then the properties would be offered to other federal, state, or local agencies, followed by nonprofits with a public use vision. Finally, they could be auctioned off to anyone.

American Rivers, a nonprofit that works to restore free-flowing rivers around the country by removing dams, falls second-to-last on that list. But advocates are already mobilizing in the Twin Cities to make sure the public understands their dream of axing Lock and Dam No. 1, and potentially the Lower St. Anthony Lock as well.

There are many benefits to removing one or more of the dams, said American Rivers' Brian Graber.

These include putting dramatic rapids in downtown, which no other U.S. city has. It could replenish native fish and mussels, giving them a fighting chance to compete with invasive species, while spawning new kinds of waterplay like innertubing, whitewater rafting, and flyfishing. And no dam means no taxpayer-funded dam maintenance.

But the people of the Twin Cities need to want that, Graber says, or there would be no point.

Thursday's community meeting in Longfellow was the first time American Rivers presented its idea to the public. Though those in attendence seemed intrigued, technical details are far down the road, and there are plenty of other proposals to think about.

One idea that's been gaining traction this summer is to build a state-of-the-art new visitor center run by the National Park Service for the Upper St. Anthony Lock. Minneapolis Parks and Recreation is continuously remodeling the riverfront, which should prioritize giving north Minneapolis access to the river, according to Friends of the Mississippi River. And the Minneapolis Rowing Club came out in strong opposition to removing Lock and Dam No. 1 because it would eradicate the reservoir that rowers use.