Changing TVA operations not without trade-offs

By Kathy Helms-Hughes

   Tennessee Valley Authority wants to rebalance its reservoir system and is considering changing operations systemwide to get the most value and better serve its customers.
   The nation's largest public power producer has identified 12 objectives, such as increasing hydropower production, navigation, and opportunities for recreation.
   After screening 65 preliminary alternatives, TVA whittled the options down to 25. That set of policy alternatives underwent more screening and computer modeling, resulting in 18 alternatives being eliminated.
   TVA is now considering the remaining seven alternatives as a "Base Case" option in a Draft Environmental Impact Statement (EIS). TVA presented its findings at a Reservoir Operations workshop Thursday night at The Centre in Bristol and will be taking comments from the public through Sept. 5. Those will be used to develop a final EIS and a preferred alternative.
   The water in Watauga and Wilbur Lakes helps make up the Watauga Reservoir system. Watauga's water empties into Cherokee and other reservoirs, travels down the Tennessee River past Chattanooga, and eventually winds up in the mighty Mississippi.
   According to Gil Francis, TVA media relations, the Tennessee River system tributaries look like a giant hand "because the watershed goes up into Southwest Virginia [and] into the mountains of Georgia and North Carolina. There's a lot of water that's got to flow down the Tennessee River and eventually out."
   The TVA system was designed to alleviate flooding that usually occurred twice a year. In 1991, the utility began upgrading its aging hydropower plants to improve efficiency and increase generating capacity. To date, 40 hydro units have been upgraded; 21 are being designed or constructed, and 31 are under consideration but have not been started, according to the EIS.
   TVA also is switching to a Hydro Automation Program, which will allow all dam functions to be handled by remote and local computers from the Hydro Dispatch Control Cell at the Power System Operations Center in Chattanooga.
   According to Mark Pipkin, local production manager for TVA's hydro operations, the operations staff can look at the river system during a significant rain event and pinpoint where there might be a big pocket of water, or perhaps a bottleneck, and identify options to alleviate the greatest potential for flooding.
   "The reason that's important is because the next dam down river has got to know how much water we're releasing so they can be prepared." They will also know a timeframe for its arrival. Water travels roughly 7 mph, he said, meaning it takes about 40 minutes for a release to go from Boone Dam to Fort Patrick Henry, and approximately 17 hours to flow from Fort Henry on to Cherokee Dam.
   Because this river system is interconnected, a state of unbalance in one area could affect the rest of the system. In the River Operations EIS, TVA evaluated the trade-offs between competing reservoir operating objectives and weighed them against public input, impacts to environmental resources, and economic benefits.
   The Base Case documents current reservoir operations policy and includes a number of actions that will occur regardless of policy changes. Those include taking into account an increasing future demand for drinking water, bringing Browns Ferry Nuclear Plant's Unit 1 back on line and extending the life expectancy of the plant's three units another 20 years, as well as increasing power generating capacity; and operating the Tennessee-Tombigbee waterway at full capacity.
   According to TVA, only about 5 percent of the Tennessee River basin's water goes for consumptive water use and is not returned to the river system -- the lowest rate in the United States. By 2030, that figure is projected to still be below 14 percent, or 1.7 billion gallons a day.
   Among the alternatives identified by TVA, Reservoir Recreation Alternative A would extend the summer pool period one month, delaying the annual drawdown on Watauga, South Holston, Cherokee, Douglas, Fontana, Chatuge, Nottely, Hiwassee, Blue Ridge and Norris until Labor Day.
   Under Reservoir Recreation Alternative B, reservoir releases would be limited to minimum flows from June 1 to Labor Day, with the exception of Chickamauga, which would remain at the Base Case minimum release level of 13,000 cubic feet per second (cfs).
   The Summer Hydropower Alternative would allow unrestricted drawdown immediately after June 1 to increase power production and flood storage volume. Weekly releases from Chickamauga would be increased to 35,000 cubic feet per second, compared to 13,000 bi-weekly under the Base Case. No tailwater releases would be made for recreation, except for Ocoee #2 Reservoir.
   Increasing hydropower production would lower reservoir levels and decrease recreational opportunities throughout summer and fall, according to TVA. At the end of summer, the lower reservoir levels resulting from increased hydro production also could affect water quality and water temperatures at TVA's nuclear and fossil plants.
   Restarting Browns Ferry Unit 1 will require constructing another cooling tower and increasing water intake by about 10 percent.
   Another option studied by TVA is the Commercial Navigation Alternative, which is aimed at operating the reservoir system to increase reliability and reduce the cost of commercial navigation on the Tennessee River. Under this alternative, the navigation channel depth would be increased to 13 feet, providing 11 feet for navigation with a 2-foot overdraft. Minimum flows would be increased at key lower river projects and major navigation locks.
   The Commercial Navigation Alternative is expected to enhance barge traffic while decreasing costs and providing a positive economic impact. On the other hand, recreation would be negatively affected systemwide. A decrease in hydropower generation could result in more reliance on fossil fuel combustion, which would create more air pollutant emissions.
   Each of the seven alternatives would have some economic or social impact. The Base Case Alternative would leave operations as they now are with no change in impact.
   Reservoir Recreation Alternatives A and B would increase recreation spending and positively affect the economy, but TVA says power costs would rise. The Summer Hydropower Alternative would have a negative impact on recreation and would not measurably lower power costs.
   Other alternatives and their impacts are listed in the Reservoir Operations Study Draft Programmatic Environmental Impact Statement on TVA's Web site ( Public comments are due by Sept. 5 and may be faxed to TVA at (865) 632-3146. Send written comments to: ROS Project Manager David Nye, TVA, c/o WT 11A, 400 West Summit Hill Drive, Knoxville, TN 37902.