TVA officials said Tuesday that waters were reaching flood stage at Chattanooga.
Officials said the water from recent heavy rains was reaching near the top of the gate at Chickamauga Dam.
Those downstream were being cautioned to secure their boats and boathouses.
Meanwhile, a woman narrowly averted drowning in Hixson. Brandy Tompkin tried to drive across a section of Old Hixson Pike that was covered with water. She said she got partway across, then decided to back up. But the car stalled and began to be carried away.
She managed to crawl out of the driver's side window just before the car went under.
She called for help on a cell phone and rescuers from the Volunteer State Rescue Squad were able to reach her in a boat after about 45 minutes.
Officials said the water level was duexpected to reach 30 feet at the Walnut Street Bridge early Tuesday afternoon.
TVA spokesman Randy Battles said significant flooding could occur in Chattanooga if downpours continued between Knoxville and Chattanooga.
There was a break in the weather Tuesday afternoon, but 1-3 inches of rain was predicted for Wednesday.
Mr. Battles said 120 million gallons of water were flowing past Chickamauga Dam compared to a normal flow of 30 million.
TVA officials said all available reservoirs were being used to capacity.
Tributaries, including Cherokee and Douglas, were being shut off.
TVA put out this flood fact sheet:
MAJOR FLOOD CONTROL OPERATION
MAY 6, 2003
Because of heavy rainfall, TVA is in a major flood control operation and is managing the river system to minimize flood impacts.
We expect the Tennessee River to be at flood stage at Chattanooga by early afternoon.
A decision will be made on managing water levels at Chattanooga later this afternoon.
Over the last 24 hours, there have been 5–6 inches of rain between Knoxville and Chattanooga, with high spots of more than 9 inches.
We are using all available storage space in the main reservoirs, such as Fort Loudoun and Chickamauga. These reservoirs are at or above summer pool levels.
We are using available flood control space in the tributaries to hold back as much water as we can. The tributary reservoirs, such as Cherokee and Douglas, have been shut off. The tributaries are at or near summer pool levels.
Water levels are expected to reach elevation 651.12 feet above sea level at Chattanooga, or 30-foot stage at the Walnut Street Bridge.
Fort Loudoun, Watts Bar and Chickamauga reservoirs are expected to reach the top of the gates at the dam sometime today. Dock owners should take precaution to secure their boats and equipment. Boat owners may need to move boats from covered boathouses to avoid damage to the boathouses as water rises.