* 4.9 inches — Normal January rainfall in East Tennessee
* 9.7 inches — Chattanooga rainfall total last month
* 10 inches — Tri-cities rainfall total last month
* 10.5 inches — Oak Ridge rainfall total last month
* 12.7 inches — Knoxville rainfall total last month
* 14.7 inches — Record rainfall for January in Chattanooga in 1882
Source: National Weather Service
TVA flood control
* 49 — Number of TVA dams in the Tennessee River and its tributaries
* 11 million — Acre-feet of water TVA can store in its reservoirs
* $250 million — Average yearly property savings from TVA flood control operations
Source: Tennessee Valley Authority
The dams and reservoirs of the Tennessee Valley Authority helped avert an estimated $710 million of flood damage to Chattanooga last month.
But last month's rainfall -- twice as much as in the typical January -- continues to clog river traffic along the Tennessee River artery through Chattanooga.
"It's been devastating for our operations," said Peter Serodino, president of the Chattanooga barge and towing company that bears his name. "We've been shut down for almost five weeks now. We've had to send our crews home and, except for one day, we haven't been able to operate."
With another two inches of rain forecast for the Tennessee Valley next week, TVA increased the flow of water through its dams on Wednesday to help recover more water storage in its upstream reservoirs. The faster flow from the rain-swollen river has idled barge shipments on the Tennessee River upstream of the Nickajack Dam in Marion County.
The high water also has forced the Delta Queen floating hotel to limit some of its operations over the past month at its dock at Coolidge Park in downtown Chattanooga.
But TVA's network of dams and reservoirs has been beneficial for most of the Valley, and especially Chattanooga. TVA calculates that without its dams, $800 million of flood damage would have occurred during January. Nearly 90 percent of the savings were in Chattanooga, where rainfall runoff from 20,000 square miles of land in East Tennessee, Northern Georgia, and western North Carolina and Virginia is funneled along the Tennessee River.
TVA is operating all 29 of its hydroelectric dams at full power with the available water. But the utility also is having to spill 698,000 gallons per second through the Chickamauga Dam to help draw down the rain-swollen lakes and rivers above Chattanooga.
"We try to avoid spilling water because it's low-cost power generation, but when we have a lot of water our No. 1 priority becomes flood drainage risks," said John McCormick, senior vice president of river operations at TVA. "We hold water behind the dams in order to minimize the downstream flood impacts. After the high water crested in the Tennessee River and its tributary rivers, we started gradually releasing water out of the tributary reservoirs to recover storage space and to prepare for the next rain event."
Those releases through the dam spillways are making the river too rough for barge traffic, at least in Chattanooga.
"Whenever you have these kinds of sustained rains, especially during the winter months when there is less vegetation to limit runoff, the river flows increase and we have to limit our operations," said Cline Jones, executive director for the Tennessee River Valley Association. "It's been especially bad this year."
January's rain fall was more than twice the typical level. TVA spokesman Travis Brickey said last month was the third wettest January in TVA's 80-year history.
Terry Getz, meteorologist for the National Weather Service in Morristown, said light rain is expected today, but after some clear days, more rain is expected next week in Chattanooga.
Dave Flessner is the business editor for the Times Free Press. A journalist for 35 years, Dave has been business editor and projects editor for the Chattanooga Times Free Press, city editor for The Chattanooga Times, business and county reporter for the Chattanooga Times, correspondent for the Lansing State Journal and Ingham County News in Michigan, staff writer for the Hastings Daily Tribune in Nebraska, and news director for WCBN-FM in Michigan. Dave, a native ...