When the Ohio floods its banks in and around Paducah, the damage can be widespread, bottling up traffic, damaging property and interrupting daily commerce, both on land and the river.
While putting up the floodgates, issuing road closure advisories and filling sandbags may be more visible to the general public from land, critical adjustments to river operations are also underway.
"With this extreme high water, it limits our ability to actually transit through certain areas," said Robbie Englert, Crounse Corporation senior vice president of operations.
"Smithland Locks and Dam, for one, is closed, so as far as being able to transit through there with barges that we load south of there to take to points north, we're unable to do so."
"The pipeline, if you will, is clogged for the foreseeable future. We think it may be about a week before we can move any cargo. Not just our company, but anybody, coming up the Mississippi River, the upper Mississippi ... all that stuff will immediately be backlogged in the Paducah area."
Katie Newton, public affairs specialist with the U.S. Army Corps of Engineers, Louisville District, said it's estimated that locking operations at Smithland will resume Friday, and at John T. Myers Locks and Dam -- also currently closed -- at Mount Vernon, Indiana, on Wednesday.
"Those are the only two where we don't have any navigation traffic now, so there we have a queue at both of those because the vessels are not transiting the fixed weir," she said.
Olmsted Locks and Dam has what is called a navigable pass, Englert said, and in high-water conditions when the wickets are down, vessels can pass through.
"Smithland used to have a navigable pass but in the last few years there's been an island built up there," Englert said. "There's enough water to go over the top of that pass but you would end up on top of that island, so it's not navigable."
Extreme high-water conditions have an economic impact, Englert said.
"With the high, strong currents we have to run with smaller tow sizes, which increases our operating costs," he said. "We spread our cost over the amount of time we're moving and so our cost goes up. Plus our customers are unable to receive shipments in the size they were expecting."
Safety is always the top priority, whether in high-water conditions or more normal conditions, Englert said.
"Safety first ... that's paramount," he said. "We just don't take chances with the crew. And safety is not company specific. We have a call group we belong to, an industry work group, of companies up and down the Ohio River. We talk out any problems and see what we can do to keep things safe."
Helping train mariners on the inland waterways is a primary task of the Seamen's Church Institute's Center for Maritime Education in downtown Paducah.
The CME uses simulators to train towboat pilots on different scenarios including high water, said John Arenstam, the center's assistant director.
Arenstam, a retired U.S. Coast Guard officer, said there are a number of issues that come into play in navigating extreme high-water conditions.
"There is more debris, a lot more current, and there is also a lot less vertical clearance underneath bridges," he said. "So sometimes they (pilots) have to go through different spans. There's a high-water span and a low-water span. And sometimes there's just not enough vertical clearance at all.
"And when you're in the locks and dams you're sometimes going over the navigational pass and that can be a unique challenge in itself."
The CME opened in Paducah in 1997 as the first inland river system stimulator, "and the technology since '97 has only been getting better."
A lot goes in to creating the different scenarios for simulation, Arenstam said.
"It takes a lot of work to get the current right. If the current is running faster it also runs in different directions, so we have to try to model how it feels in real life for these folks. We'll design it, they'll test it and give us feedback. And then we'll adjust the currents again."
Both Arenstam and Englert point to Paducah's unique position within the inland waterways system.
"Paducah is the hub for sure," Englert said. "What's easy to see is that once boats get to Paducah it's kind of the link to all the other river systems. Sometimes they're going up the Tennessee River, the Cumberland, or on up the Ohio."
Paducah is "unique for the river system," Arenstam said.
"One, just where we are with the river geography," he said. "Two, how many of the towing companies are in town. Three, you have the Center for Maritime Education. Four, you've got the Coast Guard National Center for Expertise for the towing vessels here in Paducah.
"And now you also have a MARAD (Maritime Administration) Gateway Office in Paducah ... a town of 25,000 people."