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Since it was built in 1945, Watauga Reservoir has never been higher on February 7 than it was on that date this year. On the same date, Cherokee was the highest since 1950, and Chatuge and Nottely were the highest since 1943.
Wet weather from September through December 2004 caused pool levels in most major tributary reservoirs to rise well above normal seasonal levels, explains Morgan Goranflo, Manager of River Scheduling. “There have been only four years in the history of the TVA reservoir system when more rain fell during the same time period, and runoff—the portion of rainfall that is not absorbed into the ground and actually empties into streams, rivers, and reservoirs—was the highest ever recorded.”
Consequently, pool levels on many reservoirs rose above flood guides. “Our focus for months was on getting levels down in order to recover flood storage space. It took much of January to get there,” says Goranflo.
Because late January and early February were drier than usual, pool levels have fallen in recent weeks. On February 7, most tributary reservoirs were below their respective flood guide elevations by an average of about two feet.
This is consistent with the new operating policy resulting from the Reservoir Operations Study, according to Goranflo. “Our policy is to keep tributary storage reservoirs as close as possible to their respective flood guide levels from June 1 through Labor Day—recognizing that water levels go up and down daily depending on rainfall and runoff. However, during the winter months, we have more operating flexibility. The operating guidelines established in the ROS for winter operations allow us to use the water to ensure the reliability of the power system, to keep power rates affordable, and to meet other needs.”
“It’s important that reservoir users understand the difference between summer and winter reservoir operations,” says Goranflo. “Based on e-mails and phone calls from the public, a lot of people expected winter levels to never go below flood guide levels. We try to keep levels close to flood guide levels in the summer, but the rest of the year our policy allows for tributary levels to be drawn down below flood guide levels. This can be critical in sustaining hydropower production, improving flows for navigation, and providing other benefits, especially during cold or dry weather conditions.”
Goranflo cites Douglas Reservoir as an example. “Based on more than 100 years of actual rainfall and runoff data, water levels in Douglas will be anywhere from flood guide to six feet below flood guide about 80 percent of the time during the winter months.
Click here to view fact sheets with graphs showing the winter elevation range you can expect to see on affected tributary reservoirs based on historical rainfall and runoff data.
Wet weather in late 2004 was a “mixed blessing”
The record runoff from September through December of 2004 was a mixed blessing, according to Goranflo. “On one hand, we were able to generate about 40 percent more electricity through hydropower than we normally do during the same time period. Any time we can use clean, inexpensive hydro, that’s a real benefit to rate-payers.”
But the wet weather resulted in other impacts to the reservoir system that were not desirable. “We experienced some problems related to navigation, for instance,” explains Goranflo. “High flows affected commercial river traffic. Locks had to be shut down on a number of reservoirs. Chickamauga was closed to navigation for almost two weeks in mid-December.”
“We also had to keep a close eye on flood events,” notes Goranflo. “In the month of September alone, we were able to prevent more than $9.5 million in property damage from locations throughout the Valley that are vulnerable to flooding. We also worked closely with the U.S. Army Corps of Engineers in Cincinnati to help minimize flooding on the lower Ohio River.”
Even what TVA managers refer to as “Special Operations” were affected by all the rainfall. Plans called for Bear Creek Reservoir to be drawn down and held at a certain level so that Franklin County could install a new water intake. Due to the wet weather, that elevation couldn’t be maintained and, therefore, the work couldn’t be completed on schedule. (See related story below.)
According to TVA biologists, results of the 2004 spring sportfish survey indicate that reservoir fish health is “amazingly good.” Among 14,000 fish collected over a two-and-a-half-month period, the incidence of parasites, disease, or poor health ran only about 3.4 percent. Fish from the main-river reservoirs were in especially good condition—robust, healthy, with a good length-to-weight ratio.
The overall catch rate for the 2004 survey was 36 fish per hour—down slightly from the 2003 survey rate of 41 fish per hour. The highest catch rate—more than 74 fish per hour—was observed on Wilson Reservoir.
Crews spent a total of 342 hours conducting sampling on 31 TVA-managed reservoirs—all the main-river reservoirs and 22 tributaries. The survey included twelve 30-minute electrofishing runs covering various habitat types on each reservoir sampled. An electric current was used to temporarily stun the fish; after they floated to the surface, they were collected by TVA crew members. The fish were then weighed, measured, and released unharmed.
Close to 150 anglers and observers participated in this year’s survey.
TVA conducts the annual survey to help determine the number, age, and general health of sportfish populations. The survey mainly targets three species of black bass—largemouth, smallmouth, and spotted—as well as black and white crappie. Results are used by state agencies to protect and improve sport fisheries.
The chart below shows the top-producing reservoir for each of the species collected.
Top-producing reservoirs for different species
2004 Spring Sportfish Survey
Why does the timing, volume, and duration of actual discharges sometimes differ from the release schedule available on TVA's LakeInfo line or on the Web?
There are several reasons, according to David Bowling, manager of TVA’s River Forecast Center. “That information is a good guideline for folks to use,” he explains, “but it’s important to remember that, in order to maximize benefits, we have to be ready to adjust to changing situations—often with very little lead time.”
Bowling and his colleagues constantly monitor the latest forecasts, but sometimes—even with the very latest technology—there are unanticipated changes in the weather.
Reservoir operating plans are projected for the next several days, and an hourly generation schedule for the next day is posted by late afternoon of the previous day. “If more rain than predicted materializes, we cut back generation to prevent flooding,” says Bowling. “By the same token, a last-minute change in the forecast may mean that we need to increase generation in order to move more water through the reservoir system before the rainfall event arrives.”
Another factor influencing changes to the release schedule is the demand for electricity. Since hydro can come online almost instantaneously, it is especially valuable during peak power demands. “One of our generating units can be up and running in about 10 minutes,” says Bowling, “while it may take several hours to power up a coal-fired unit. As demand for power fluctuates during the course of the day, hydro generation has the ability to follow that demand.” An example might be when widespread afternoon thunderstorms sweep across the Valley in the summer: as temperatures cool off and the load on the system drops, hydropower generation is cut back.
Finally, it’s helpful to be able to rely on hydropower when mechanical problems arise with other generating sources. If a large coal or nuclear generating unit experiences an unplanned outage, hydro can help make up the difference.
“Whether it’s an outfitter trying to schedule a rafting trip, an angler planning a fishing trip, or a barge operator figuring on how much water his towboat will have to push against coming upstream, we understand that there are a lot of people who look to our release schedule and want to be able to count on accurate information,” says Bowling. “TVA makes every effort to provide timely and reliable release schedules—often making revisions during the course of the day. Still, there is that ongoing need for flexibility. We’d like for folks to know that they are receiving greater benefits from the reservoir system when the freedom is there to make last-minute changes to the generating schedule.”
While the terms “lake” and “reservoir” might seem interchangeable, there are some important differences. Lakes are formed by glaciers, volcanic eruptions, the movement of the earth’s crust, and other natural processes. Reservoirs are formed by humans when they build dams along rivers to impound the water for a specific purpose.
TVA–managed reservoirs were created to reduce flood damage and to maintain a navigable channel. The stored water also is used to generate electricity—between 7 and 10 percent of TVA’s total generation.
To provide these benefits, reservoir levels go up and down throughout the year. Lake levels, on the other hand, are generally stable.
So the next time you’re out on a TVA “lake,” remember that it’s actually a reservoir—working to provide multiple benefits to people all across the Valley.
TVA has installed signs, warning horns, and strobe lights at Watts Bar and Fort Loudoun dams to warn the public before TVA begins generating power and releasing water from the dams.
“The horns and strobe lights will be activated automatically prior to water-level changes as a safety warning to the public,” says TVA Senior Vice President of River Operations Janet Herrin. “When the horns and strobe lights are activated, boaters and the public should move quickly to safe areas.”
Before TVA begins generating power and releasing water from the dams, two warning horns and two strobe lights mounted on a hand rail on the promenade deck above the discharge area will be activated.
Before water is released through the spillway at the dams, four strobe lights and two warning horns mounted near an electronic message sign on both sides of the dams will be activated. Message boards will display information that water will be spilled soon.
The Shoals Environmental Alliance (SEA), a citizens’ group formed to preserve the natural resources, scenic beauty, and recreational opportunities of the Muscle Shoals area of northwest Alabama, recently received international recognition as the 2004 Community Partner of the Year from the Wildlife Habitat Council. The Wildlife Habitat Council is a nonprofit organization dedicated to increasing the quality and amount of wildlife habitat on corporate, private, and public lands.
SEA was nominated for the award by TVA’s Pickwick-Wheeler Watershed Team in recognition of the group’s efforts to establish an interpretive native-plant garden at TVA’s Muscle Shoals/Wilson Dam Reservation in Alabama. The SEA coalition includes members from the Alabama Wildflower Society of the Shoals, Men’s Garden Club of the Shoals, Shoals Master Gardeners, Shoals Audubon Society, and many other volunteers.
The project resulted in the donation of more than $21,000 in materials and supplies, including an irrigation system and more than 1,300 native plants. SEA has coordinated numerous volunteer workdays and sponsored guided wildflower walks, hikes, bike rides, birding walks, and other events over the past two years. The group also has made a long-term commitment to maintain the garden by providing one workday per month.
“SEA’s efforts and leadership have greatly expanded the scope and effectiveness of wildlife-management programs on the Muscle Shoals Reservation,” says Ken Kelley, Watershed Supervisor for the Pickwick-Wheeler Watershed Team. “They’ve given their time and money and worked tirelessly to make this ambitious project a reality.”
It’s a magnificent sight, but you’ll need to hurry to catch them before they leave. The eastern sandhill cranes are almost ready to head back north, after having spent most of the winter months at TVA’s Hiwassee National Wildlife Refuge.
In the past, the Refuge was only a stopover—a halfway point in the migration route from the Great Lakes to central Florida. But a huge number of the birds (estimates are around 14,000) are now choosing to spend the winter at Hiwassee.
The Refuge, managed by the Tennessee Wildlife Resources Agency, is an ideal spot for the cranes to forage and for folks to view them on the ground. It features shallow water and mudflats, as well as fields planted in corn.
But Hiwassee Island isn’t the only location in the Valley where you might catch a glimpse of the cranes. A couple hundred of the sandhills are spending time at the Wheeler National Wildlife Refuge in Alabama—and a few of the much rarer whooping cranes have been observed there, as well.
If you miss them this time, you’ll have another chance next fall. The first sandhills usually arrive at Hiwassee in October. Their numbers increase during November and December, and they reach peak population in January.
Bear Creek Dam, an earthen dam located in the northwestern portion of Alabama near the Mississippi border, is being repaired to ensure its integrity.
Like all earthen dams, some water will always slowly flow and/or seep through the dam. This seepage is typically collected in drainpipes, then measured below the dam to monitor changes.
Since completion in 1969, however, seepage at Bear Creek Dam has been a problem. In 1972, a major foundation drilling and grouting project was completed, which reduced the seepage. However, since then, the seepage has slowly increased.
A new drilling and grouting project was started in the fall of 2004 to intercept this seepage. During this drilling, an open cavity about two feet high was found under the dam above the rock foundation. Testing showed that this open cavity was directly connected to the drain pipes. In addition, a sinkhole developed downstream of the dam while the reservoir was at near-record elevation in December, and other sinkholes were found in the floor of the reservoir after it was lowered.
TVA is in the process of drilling and grouting the dam’s foundation, improving the downstream drainage system, probing for additional cavities, and filling the sinkholes.
To help ensure the safety of the dam structure, to allow for repairs, and to preserve some flood storage, the reservoir level is being maintained around elevation 550. However, because the sluice pipe which allows water to be passed from Bear Creek Reservoir to downstream of the dam is only nine feet in diameter, the reservoir could rise substantially during flood events.
If the reservoir rises above elevation 565, TVA will alert the local authorities of the increased hazard and will initiate special inspections on a daily or more frequent basis. However, failure of the dam before repairs are completed is unlikely.
Before raising the reservoir elevation back to normal, TVA will make sure the repairs are complete and effective. No date has been set for completing the work.
The TVA Board has appointed members for the third term of the Regional Resource Stewardship Council, which was created to provide advice and counsel to TVA on the management of natural resources in the Tennessee Valley.
The 20-member council was established in 2000 under the Federal Advisory Committee Act, which sets guidelines for establishing a group that provides advice or makes recommendations to a federal agency.
“The dedication and commitment of the men and women who serve on this council are invaluable to TVA as we manage the natural resources for the benefit of the people we serve,” says Chairman Glenn McCullough Jr. “We appreciate their input and are committed to the council’s continued success.”
The TVA Board appointed members to the third-term council after receiving nominations from governors of the states TVA serves and recommendations from TVA customer organizations, community officials and other stakeholder groups. The first meeting of the new council is scheduled for March 16-17 in Knoxville and is open to the public.
“In its first two terms, the council provided valuable advice on TVA’s stewardship programs and activities,” says Director Skila Harris. “The council’s advice helped TVA conduct a major revision of its reservoir operating policy and implement improvements in the way TVA conducts its land-management, recreation, water-supply and public-participation efforts.”
New members nominated by governors are Kenneth Ray Darnell, Murray, Ky.; Jim Fyke, Nashville; Alabama State Sen. Tommy Ed Roberts, Hartselle, Ala.; and Rosemary Williams, Corinth, Miss.
New members nominated by TVA’s directly served and distributor customers are Jim Jared, New Johnsonville, Tenn.; and Roy G. (Joe) Satterfield Jr., Young Harris, Ga. New members appointed based on recommendations by stakeholders are Mike Butler, Nashville; Tom Littlepage, Montgomery, Ala.; and Bill Tittle, Chattanooga.
Members reappointed by governors are Bill Forsyth, Murphy, N.C.; W.C. Nelson Jr., Blairsville, Ga.; and Jackie Shelton, Pennington Gap, Va.
Returning council members are Jimmy Barnett, Sheffield, Ala.; Austin Carroll, Hopkinsville, Ky.; Phil Comer, Dandridge, Tenn.; Karl Dudley, Selmer, Tenn.; Miles Mennell, Nashville; Bruce Shupp, Guntersville, Ala.; Greer Tidwell Jr., Nashville; and Tom Vorholt, Nashville.
Members will serve through February 2006 in accordance with the Federal Advisory Committee Act.
New information about how TVA limits the effects of flooding is available on our Flood Damage Reduction page. Find out when and where floods are most likely to occur in the Tennessee Valley, how much flood storage space is available in each reservoir, what TVA does when a storm hits, and more.
Interested in applying for a permit from TVA for a water intake? Do you want to know how to improve water quality around your intake? Curious about interbasin transfers? Get answers to these and other frequently asked questions on TVA’s Water Supply Web site.
And don’t forget about the redesigned Reservoir Information section on tva.com. You’ll find detailed information about individual TVA reservoirs, including observed and predicted elevations and releases at dams, reservoir operating guides, dissolved oxygen improvements, fish population survey results, recreation facilities, and more.
In some cases, phone numbers and/or the mailing address for the offices of TVA Watershed Teams have changed. For questions about the use of TVA-managed public land, for help in applying for a permit, or to learn more about how to get involved in watershed improvement activities, refer to the numbers below or click here for office addresses.