The Tennessee River will be a no-shipping zone this weekend as TVA draws down its rain-swollen reservoirs to prevent future flooding.
For Chattanooga-based shipper Serodino Inc., that means 75,000 tons of cargo -- the equivalent of 3,000 truckloads -- will sit in the river, waiting out the draining.
"It causes time delays, of course, and much of our business activity halts," said Peter Serodino Jr., who helps run his father's company. "Idle time is a cost. We're not burning near as much fuel, but capital costs and labor costs continue."
The Tennessee Valley Authority boosted the amount of water spilling and flowing through the Chickamauga Dam on Friday from about 35,000 cubic feet per second to 95,000 cubic feet per second. The higher flow increased the amount of water flowing over the Chickamauga Dam to the equivalent of more than 42 million gallons of water per minute, TVA spokesman Travis Brickey said.
The higher spill rate is expected to raise the level of the Tennessee River as it flows through downtown Chattanooga by up to 1.5 feet, but the extra flow will drain reservoirs needed to prevent serious flooding in the future.
For shippers, manageable flood risks are usually preferred to the other weather extreme.
"We always say, it is much better to have a little bit too much water in the river than not enough," Serodino said. "Working with mother nature, sometimes delays are expected."
The weather has been particularly harsh recently. Over the last four months, rainfall has been about 150 to 160 percent higher than normal, according to Tom Barnett, manager of TVA's River Forecast Center.
"Really, it's just an aggravation," said Cline Jones, executive director of the Tennessee River Valley Association, which promotes river commerce. "It's just planning and pre-positioning. One of the last things you want when you have high water is barges breaking free."
According to U.S. Corps of Engineers regulations, barge traffic on the river is halted when the river flow reaches 90,000 feet per second or more in the Tennessee River gorge just west of downtown Chattanooga.
Over the last week and a half, Chattanooga saw between four and five inches of rain, according to Tod Hyslop, a National Weather Service meteorologist. On Thursday and Friday alone, Chattanooga saw more than three inches of rain.
"Normally we're not getting so many periods of rain," Hyslop said. "It's an active season we're having."
Floods are always a concern this time of year. Without living vegetation to absorb the rain or warm weather to evaporate it, water levels are far more likely to rise.
If it weren't for periodic river shutdowns such as this weekend's, the Chattanooga area could see annual flood damage totaling more than $200 million, Barnett said.
Brickey said TVA expects to continue the elevated spill rate at most of its dams until the first of next week.