Workers operate Chickamauga Dam hydro units. Staff photo by Dave Flessner

As the Tennessee Valley Authority prepares to revamp its future power generation plans, the federal utility Thursday celebrated its record success in getting power from its oldest source of power.

Mother Nature provided a bit of manna from heaven for TVA in fiscal 2013 with near-record rains swelling TVA's reservoirs and helping the utility generate a record amount of power from its 29 hydroelectric dams.

TVA's hydro generation -- its oldest and cheapest source of electricity generation -- rose to 18.5 million megawatt hours during the 12 months ended Sept. 30. That bested the previous record set in 1973 and was the highest in the 80-year history of TVA.

"It's been one of our wettest years ever so we've run our hydro units more often and longer than at any previous time," Chickamauga Hydroelectric Manager Tony Townsend told visiting journalists Thursday. "We've helped avert floods and generate a record amount of power."

Townsend said the floodgates at Chickamauga were opened 800 times so far this year, twice the normal level. TVA raises and lowers its reservoir levels to help flood control and to maintain navigation, recreation and power generation along the 652 miles of the Tennessee River.

The 7-state Tennessee Valley received nearly 62 inches of rainfall in the fiscal year ended Sept. 30, or more than 10 inches above the precipitation in a typical year. The heavy rains generated 30 percent more water runoff into TVA reservoirs, allowing the utility to run its hydro units around the clock during parts of the year.

TVA also estimates it saved about $800 million in flood damages in January, primarily by protecting low-lying areas of Chattanooga that would have flooded after heavy winter rains pushed the Tennessee River higher. Another $48 in damages was averted by TVA following heavy rains in July.

In an average year, TVA estimates it saves about $250 million in flood damage.

"TVA was able to reduce flooding impacts during large events throughout the year," TVA Vice President John McCormick said in a statement Thursday. "In a typical year, conventional hydroelectric power makes up about 8 to 10 percent of TVA's total electricity production, with the bulk of our generation coming from nuclear, coal and natural gas. But in fiscal 2013, hydroelectric power contributed about 13 percent of the generation mix."

TVA is beginning a new Integrated Resource Plan to outline the power generation options for the future. A stakeholders group will help review the recommendations, which are expected late next year.

Contact Dave Flessner at dflessner@timesfreepress.com or at 757-6340.