Judging from feedback I have received, my Sunday column (linked here, and pasted below) obviously did not answer everyone's questions about the fate of the locks and commercial river traffic in Minneapolis. Here are the ones I can answer:

Why not close the lower two locks, since there are no port facilities in Minneapolis below the city's soon-to-be closed terminal?

Congress only authorized the closure of the Upper St. Anthony Lock and Dam. The lower two locks will still accommodate traffic, although it will likely be recreational craft only.

What will happen to all of the goods currently being shipped by barge in Minneapolis?

Expect more trucks bearing scrap metal and aggregates rolling to and from the North Side.

Would the lock operate for a lone paddler?

Yes, and I speak from experience, having traveled downstream through Lock and Dam #1 (at the Ford Bridge) in a canoe.

Here's the column:

The long-lived dream of river commerce in Minneapolis officially ended a few weeks ago, laid to rest by the stroke of a presidential pen.

Three paragraphs submerged in the Water Resources Reform and Development Act of 2014, signed by President Obama on June 10, order the U.S. Army Corps of Engineers to close the Upper St. Anthony Falls Lock within one year.

By next spring, the last barge or pleasure boat will take a 49-foot vertical ride in the concrete channel, exit through the mighty gates and the lock will close forever to river traffic. Local leaders think the extraordinary measure will keep the hated invasive carp from swimming upstream and muscling out our beloved local fishes.

What the closure of the 51-year-old lock won't do is save much money for taxpayers. The Corps of Engineers, which has beenreshaping the Mississippi River's only natural waterfall since 1869, is here to stay.

Aaron Snyder, the corps' district chief of project management, said that the law merely orders the lock closed, but it doesn't tell the corps what to do with it afterward. So Snyder and his colleagues in the St. Paul District await word from headquarters in Washington on what to do next.

No matter what happens, Minneapolis has finally let go of its vision of a bustling river terminal on the North Side, loading the bounty of the Midwest onto fleets of barges headed for the world downstream.

The idea of Minneapolis becoming a major port was so far-fetched that even the corps, usually an enthusiastic dredger, was dubious. It tried to pull out in the 1950s, saying the project would never pay for itself, but Minneapolis' obsession pushed it forward.

Workers knocked out a vault in the Stone Arch Bridge and replaced it with an ugly trestle, so ships would have clearance. Then the deepest and most expensive ($38 million) lock system on the Mississippi River opened on Sept. 21, 1963. Politicians celebrated as a towboat pushed a barge full of cast-iron pipes through a red ribbon strung across the lock.

Two hours later, the barge was pushed back downstream to the Minnesota River, because Minneapolis didn't have any place to unload the plumbing.

The city developed its Upper Harbor Terminal in the late 1960s and early '70s at a cost of at least $7 million. Driven by coal and grain, the tonnage moving through the lock peaked at 3.1 million in 1976.

These days, it's mostly sand, gravel, fertilizer and scrap metal on local barges. This season, interrupted by a late thaw and high water, only 202,500 tons had moved through the locks by July 15.

Earlier this year, the City Council voted to stop funding the money-losing Upper Harbor Terminal. The corps cannot do the same with the Upper St. Anthony lock, which cost about $762,000 last year to operate. The Lower St. Anthony Lock and Lock and Dam No. 1 will remain open to traffic, while Upper St. Anthony has to stay operational for flood control.

The corps likely will reassign the four lock operators at Upper St. Anthony to the other locks, leaving one maintenance worker on site.

On July 7, less than a month after Obama signed the law closing the lock, the corps put out a request for bids to replace the lock's electrical equipment. The anticipated cost: $250,000 to $500,000. Snyder said the need became clear after the sluggish performance of a special flood gate, deployed this year for only the sixth time since the lock opened.

Something beyond jobs and business will be lost when the last towboat chugs with its cargo down the Mississippi next spring.

The spectacle of churning waters lifting a vessel above the falls always attracts a crowd on the Stone Arch Bridge, because they know they're watching something elemental, the power of metal and concrete and electricity to tame the Mississippi.

A career on the river called to Greg Genz ever since he stepped on his first towboat as a child. Genz, president of the Upper Mississippi Waterway Association, which represents the river industry, thinks that despite its declining traffic, the city could have saved its port. Genz says the interests of riverfront real estate developers won out over the need for a working river.

"I rode the last commercial barge off the St. Croix River," Genz said. "I guess I'm going to try to ride the last one out of Minneapolis."