August 2007

Toccoa Tailwater Status Report

During their July program, members of the Blue Ridge Mountain Chapter of TU were relieved to learn that the fish they pursue in the Toccoa tailwater are not likely to suffer any adverse impact during the impending deep draw-down of Blue Ridge Reservoir. However, while the trout will be “happy” with conditions on the tailwater, anglers may not be all the time. In all likelihood, juggling fishing outings around a TVA generating schedule that places little priority on anglers’ desires is going to continue.

This information came from Dr. Wayne Poppe, TVA’s Senior Manager of River Operations, who

met with the Blue Ridge TU group on July 14 when Poppe said the TVA is struggling to operate its reservoirs in the Tennessee River System through the worst drought that has occurred during the 118 years that records have been kept. Poppe said extremes in weather – drought or flood – present challenges for managing the flow of water through the system, but droughts are the most frustrating. “A flood is like the flu – it comes on fast, is bad for a few days, but then its gone, “ Poppe said. “But a drought is like a migraine headache that just won’t go away.” Recent rains have helped the situation, he said, but lake levels have already been affected to the point it’s going to take time to recover.

Poppe reported that a long-term work project involving renovations to the Blue Ridge dam that was constructed almost 100 years ago is continuing. So far a spillway was added at the dam in 1993 and a low-level outlet put in during 2004 which consists of a 1,000-foot-long 12-foot-diameter tunnel drilled through the bedrock underneath the earthen dam. The next, and final phase, of the project will be a deep draw-down of the reservoir so three objectives can be accomplished: 1) repairing the penstock that buckled when the lake originally filled; 2) stabilizing the intake tower located in the lake just out from the dam by adding more concrete to the structure; and 3) adding mass to the dam on both the “upstream” and “downstream” sides to bring it up to today’s safety standards.

Poppe said right now, it is not known when the deep draw-down will begin. He said TVA is in the design phase now and this will take at least until late winter to complete. At that time, the designs will be reviewed by various parties to make sure the engineering and plans are optimum, followed by any revisions that may be necessary. Then the project will go to the contract development and financing phases before actual construction will ever start. With all that must be done, Poppe said he would not even venture a guess on when the draw-down will start.

However, he did say that as far as maintaining water quality in the tailwater during the project goes, “I don’t see any issue with this. If you are a trout, you’ll be happy.”

While he will not know exactly how low the lake level will go during the deep draw-down until the design plans for the renovations are completed, it won’t be a situation where the river is running unchecked across a then exposed lake bed. A weir dam will be constructed around the penstock work area and he expects water levels will remain at depths that maintain a thermocline for cold water releases. Even when the water is exiting the dam through the low level discharge rather than the generator, it will be oxygenated by an aeration system built into the release system valves. Poppe said minimum flows would be maintained, not just for the biological health of the river, but also to keep the intake pipes covered with water for the three municipal water systems that draw from the Toccoa tailwater.

Another bit of good information for anglers shared by Poppe is that a tailwater generation warning system will be funded and installed by TVA during FY08. Poppe said TVA is looking at warning systems for all their dams. He said plans vary from dam to dam due to topography and other factors and the system that will be installed at Blue Ridge Dam has not been developed yet, but it will include audio and visual alerts that generation is beginning.

The news was not as good for anglers concerning the information Poppe shared about TVA generating schedules. Rather than giving much consideration to fishermen having Saturday mornings on the river with minimum flows, TVA operates the generators strictly based on electrical load management of their power grid, Poppe said. He said this is partially based on providing the electricity demanded by the 8-million consumers who get their power from TVA facilities, but also on voltage load maintenance on the system. Poppe said this latter factor (which he explained in lots more detail) is more of a factor in setting generation schedules for the facilities on the fringes of the system like Blue Ridge.

While load management trumps other factors as far as generating times go, Poppe pointed out that TVA is concerned about environmental factors – including trout habitat – in the tailwaters. He said across the TVA system millions of dollars have been spent to upgrade water quality. These measures include such things as the oxygenation system at Blue Ridge dam and the “little generator” that ensures a minimum flow down the tailwater.

The Blue Ridge Dam generating schedule is also not geared around the Ocoee rafting interests, according to Poppe, reiterating that load management has the highest priority. He said minimum flow from the Blue Ridge Dam is capable of providing the amount of water needed for rafting on the Ocoee. He said there is a contract between the TVA and the whitewater industry to provide specified flows, but this is to compensate TVA for the loss of electricity that occurs when water is released for whitewater recreation rather then generation. From a holding reservoir near Copperhill, water is spilled directly into the Ocoee for whitewater purposes, Poppe said, rather than being run through the flume to the generators at Ocoee #1 and #2. “We can’t generate when the rafters are riding,” Poppe said.

As for deviations from the posted generating times on the toll-free phone system and the internet, Poppe said there is no  way to anticipate all the system-wide factors that may necessitate last-minutes changes and these should always be anticipated. He said because there will always be unannounced generating periods, the TVA considered not even publicizing the planned schedules. But for the most part, the schedules are followed and river users can make plans based on them while remaining alert to the warning they hear on the phone and read on the internet:  “Please note! Use caution near dams. Water release schedules often change without notice due to unanticipated changes in weather conditions and power system requirements.”

This was the second time in recent years that Dr. Poppe has presented the Blue Ridge TU Chapter’s program and both times resulted in those present receiving much good information about the TVA in general and the Toccoa tailwater in particular.