Objects that were underwater for years - from the remnants of a sunken wooden barge to a flip-style cellphone - now sit on dry land.
"I have never seen anything like it," said Col. Chris Hall, commander of the Corps of Engineers' St. Louis District. "We're just trying to stay ahead of the potential problem areas we know of."
Water levels are low along the entire length of the river, but the corps says the worst stretch is from St. Louis to Cairo, Ill., where the Ohio River flows into the Mississippi.
The agency is scrambling to keep the shipping channel at least 9 feet deep and 300 feet wide - the minimum depth and width needed so barges can travel safely.
That requires dredging the river around the clock between St. Louis and Cairo, using barge-mounted backhoes to scoop huge chunks of rock from the river bottom and pumping sediment to the sides of the river.
The corps has begun closing the river near Thebes, Ill., every day from 6 a.m. to 10 p.m. for dredging. On Dec. 21, contractors began using explosives to blast away underwater rock pinnacles near Thebes that threaten to tear open the bottoms of barges trying to squeeze by.
The blasting near Thebes, just upriver from Cairo, is the first since the river dropped during the drought in the late 1980s, according to the corps.
Despite those measures, Hall acknowledged that a complete closing of some parts of the river is "always a possibility."
The closings near Thebes, which are expected to last at least through the end of January, have forced towboat operators to park their barges on the side of the river for hours, like truckers waiting out a traffic jam at a roadside rest area.
Even when barges are allowed to pass through the area overnight, traffic can move in only one direction at a time.
"It's nice to get a break, but this is not the type of break I was looking for," Cox said as his towboat idled in the river, already hours late for its scheduled arrival in Cairo.
While the corps plays the role of a highway maintenance department on the river, the Coast Guard serves as the highway patrol, directing barge traffic to keep boats from running aground or colliding.
The Coast Guard set up a mobile command post - a trailer outfitted with GPS systems and other tracking equipment - in a parking lot overlooking the river just north of Cape Girardeau, Mo., at the top of a boat launch ramp that no longer reaches the water.
"We're trying to keep that traffic moving as long as we can, as safely as we can," said Capt. Byron Black, commander of the Coast Guard's operations on the Mississippi River north of Cairo.
But with the Mississippi continuing to drop, the corps began releasing water into the river from Carlyle Lake in south central Illinois on Dec. 15, an effort that should provide an additional 6 inches of depth at Thebes this week.
Still, some barge industry officials and lawmakers from states along the Mississippi are urging the corps to increase the amount of water flowing into the Mississippi from the Missouri River, a step they say is critical to keeping the shipping channel open.
But that option is opposed by both the corps and states in the Upper Midwest that rely on the Missouri River for transportation and recreation.
The corps' position is that it cannot compromise water levels on the Missouri River just to help the Mississippi, and that the Missouri River's water must be conserved in case the Midwest's drought stretches on for years, Petersen said.
"It's difficult to manage water resources in a good year because of all the considerations we have to take (into account)," Petersen said. "But when we're in a drought, every decision becomes critical, and we have to keep our eyes on the long term."
For towboat operators on the Mississippi, however, the focus is on the short term - making sure their cargo and crew arrive safely, despite the challenging conditions on the river.
On the LJ Sullivan, Capt. Paul Roos relieved Cox late in the afternoon, then began steering the boat's 16 barges downriver long after sunset, when the corps reopened the shipping channel through Thebes.
As an orange sliver of moon hung low over the river, Roos weaved the massive string of barges through the shipping channel, training the boat's powerful twin spotlights on the green and red buoys lining the channel as the boat pushed its load south.
His eyes darting from the river to a GPS map to a radar screen, Roos used a steering lever to ease the barges - nearly as long as three football fields - through a 90-degree turn around a rocky point before passing the rocks near Thebes at about 6 mph.
He kept a close eye on the depth readings on a monitor in front of him, which at one point near Thebes read 10.1 feet - only about a foot more than the minimum clearance needed for his barges to pass.
"Ten foot - that gets a lot of people's attention," Roos said as he backed off on the throttle.
But by late the next morning, he had safely delivered his barges in Cairo and was preparing to pick up another string of barges for his next trip.
For the 39-year veteran of Mississippi River towboats, the lessons he learned when he first started working on the river apply now more than ever.
"Don't ever think you've mastered it," he said, standing behind the boat's control panel in Cairo. "The day you think you've mastered it, it will humble you. Overconfidence is not a good trait out here."
Most Popular Stories
- Apple Wants Samsung to Pay $22M for Patent Dispute Legal Bills
- Twitter Coming to Phones Without Internet
- NASA Fellowships, Scholarships Bring Diversity to Workforce
- Dish Network Leads 2013 Top 50 Advertisers List
- Networks Vie for U.S. Hispanic TV Viewers
- Ad Counts Rise in 2013 for Hispanic Magazines
- Entravision Initiates Quarterly Cash Dividend
- Jobs Report Brings Cheer As Unemployment Drops to Five-year Low
- Starbucks Gets Grinchy; No Gingerbread Lattes for Tampa Customers
- Warner Bros. Unleashes 'Hobbit: Desolation of Smaug' Merchandise