The National Weather Service predicts heavy rain this weekend.
TVA is trying to move as much water as possible before then.
TVA is already spilling on the entire main stem of the Tennessee River but may need to spill more after this weekend.
At the TVA River Forecast Center, Operations Support Manager James Everett said they have already changed some spilling.
TVA increased spilling at Kentucky Dam and slightly decreased it at Guntersville Dam on Friday.
"Flows are high on the Tennessee River currently. We are running forecast models several times a day to update river elevations and change our operations as needed whenever it does start raining," Everett said.
Depending on rainfall, starting as early as Sunday, TVA could increase spilling on the main dams then do the same to tributary dams within the next week.
"In April we got about two inches more than normal. We normally see about four to five inches of rain in April and we saw about 6.5 inches of rain in the valley above Chattanooga so we have seen more rain than normal," Everett said.
On Friday afternoon, TVA stopped spilling at Norris Dam because of some prior recreation commitments.
TVA may spill at the dam again after this weekend.