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TVA River Neighbors

July 6, 2011

In this issue:
Rainfall and runoff
Current reservoir conditions
Reservoir operations
Special projects update

Lake information app now available
Results of 2011 Spring Sportfish Survey
More TVA information

It's back! The "River Neighbors" name is one we find ourselves returning to, once more. It seems to more closely capture the special relationship we share with stakeholders, and we hope it's one you'll recognize and relate to.

TVA provides these monthly updates on the operation of the reservoir system by email. We sincerely welcome your comments and questions. To provide feedback, sign up for future updates, change your email address, or be removed from this distribution list, please contact riverneighbors@tva.com.


Rainfall and runoff

Even though it may have seemed as if we saw rain every two or three days throughout last month, in reality it was a pretty normal June in terms of precipitation.

For the part of the Valley above Chattanooga, rainfall for June 2011 was 4.8 inches, or slightly above normal, at 107%.

Runoff lags behind somewhat, and was actually slightly below normal for the month.


Current reservoir conditions

All TVA tributary reservoirs were at or above flood guide levels on July 1, with two exceptions. Elevations at Blue Ridge were still affected by the soon-to-be-completed dam rehabilitation project, and Watauga was slightly below flood guide because releases from that reservoir were used to meet recreational commitments and supply minimum flows through Fort Patrick Henry, due to a unit outage at South Holston.

Main river pools were all within normal operating zones, with the exception of Kentucky Reservoir, which was allowed to fill slightly around the first of July in support of flood control operations with the US Army Corps of Engineers on the Ohio and Mississippi Rivers.

Tributary Reservoir Levels
July 1, 2011
Observed Elevation1

July 1, 2011
Flood Guide2

South Holston



























Blue Ridge



Tims Ford






¹Elevations above mean sea level, as of 12:01 a.m. on this date

²Flood guide levels show the amount of storage allocated for flood damage reduction during different times of the year. During the summer, TVA's goal is to meet downstream flow requirements while keeping the reservoir level at the dam as close to the flood guide level as possible to support reservoir recreation. From June 1 through Labor Day, reservoir levels fall below the flood guide only when rain and runoff are insufficient to meet flow requirements. During the rest of the year, the primary objective is to keep the reservoir level at or below the flood guide to ensure there is enough space in the reservoir to store the rain and runoff from flood events.


Reservoir Operations

The summer of 2011 has been a pretty good one—so far, at least. That’s according to David Bowling, Senior Manager of TVA’s River Forecast Center. He bases that characterization on the fact that we’ve had “good rain, at nice intervals, and it’s been distributed fairly uniformly.”

But just because things haven’t been particularly challenging thus far is no reason to assume that they won’t become that way, as the season wears on. “We’re using common sense,” says Bowling. “Even though we’ve actually been able to run more than minimum flows to maintain our target levels, we all realize that things can change very quickly. We’re taking care not to deplete our resources, because the rest of July or August could easily end up being hot and dry.”

Until this point, however, TVA has been able to meet minimum flow commitments with the water that has flowed into the system—instead of having to take water out of storage to protect downstream aquatic habitat.

Bowling is comfortable making the prediction that lake users can expect good pool levels—at or above target elevations—through mid-July: “We feel very confident about that, based on the water we’ve got in the system. With current flows and the water in storage, we’re going to be in good shape for the next couple of weeks, anyway.”


Special Projects Update

Sometimes you know it’s coming; other times, you don’t. Whether an outage is planned or occurs unexpectedly, there are always difficulties associated with a generating unit at a hydroplant being out of service.

And at dams that only have a single generating unit to start with, the challenges can be significant. When those machines require maintenance or experience a malfunction, that can limit TVA’s ability to maintain pool levels and/or downstream flows.

At present, there are three such projects underway—with impacts, to one degree or another, to either reservoir levels, downstream flows, or both.

South Holston
This was a planned outage to repair cavitation damage and cracks in the turbine. Fortunately, a large valve located at South Holston can be used to pass water in order to meet minimum flow commitments. However, if it’s opened too much, that floods the location inside the hydro plant where welding is taking place. To complicate matters even further, if the volume of water passed through the valve is insufficient, the water could become too warm and harm the fish downstream. By cleaning out and opening all the discharge outlets in the downstream weir, TVA has been able to increase flows by 33% and no temperature problems have arisen. Daily monitoring for thermal issues will continue until the unit is returned to service—forecast to take place by mid-July.

Back in February, the windings in the generator failed—resulting in a forced outage. As luck would have it, spring rains causd Nottely to begin filling early this year; without the generator, there was no way to pass that water until the pool level reached the spillway level, contributing to the current high reservoir elevations. Since the end of March, TVA has been allowing water to flow over the spillway to meet downstream minimum flows, but water levels are still about two feet higher than where they should be at this time of year. The repair work is on schedule, with a goal of returning the unit to service by mid-September. Between now and then, TVA will be maintaining current levels in order to provide minimum flows through the spillway. By Labor Day, reservoir elevations are predicted to be six or seven feet higher than target levels. After such unusually high elevations, lake users may need to remind themselves that it won’t be like this again next year.

image of nottley spilling

Downstream flows below Nottely are being achieved by spilling water.

Blue Ridge
A long and labor-intensive rehabilitation project at Blue Ridge is drawing to a close: the reservoir is filling ahead of schedule and the generating unit is expected to be returned to service any day now. This was a planned outage, taking place in order to carry out measures designed to improve seismic stability and to install a new penstock liner—essentially correcting damages to the penstock that occurred when it was initially watered up, back in 1931. This very involved project will negate the need for deep drawdowns every five years, which had previously been necessary for inspection purposes. A concerted effort on the part of TVA allowed Blue Ridge to begin filling early this year, in order to take advantage of early spring rains. Although flows from the dam are still being limited to try to refill the upstream pool, downstream flow commitments are being met (in coordination with the Georgia Department of Natural Resources) to limit impacts to the trout fishery. More detailed information on the Blue Ridge rehabilitation project can be found at http://www.tva.com/river/blueridge.htm.


Free Lake information App Now Available

Check it from the boat ramp, just before you start your fishing trip. Access it in real-time, from wherever you happen to be on the shoreline. Reservoir elevations, water release schedules, operating guides, and more—all as close as your smartphone. For the first time ever, you can call up this type of information even if you’re not at your computer.

image of iphone appTVA’s web team came up with the idea of an application that would allow folks to use their mobile devices to access lake information and helped coordinate its development. After observing that lake information was the single most frequently accessed area of TVA’s website, they set about finding a way to optimize that information for smartphones.

Features of the TVA iPhone app include:

  • Current elevations for all TVA lakes
  • Water release schedules
  • Lake operating guides
  • Lock information and instructions
  • Reference guide for navigation channel markers and aids
  • Google-based maps

TVA has received a lot of positive feedback from stakeholders on both the functionality of the app and the fact that it’s been made available. Since mid-June, it’s been downloaded over 4,000 times.

That comes as no surprise to Chuck Bach, General Manager of TVA River Scheduling. “We’ve always known how important this type of information is to folks, particularly when it comes to planning their recreational activities. A smartphone app is just one more way we have of providing it to them, when and where they need it.”

Initially available only to iPhone users, the app is available at no charge through the iTunes App Store. It will also work on the iPad and the iPod Touch. An Android-based version will debut soon, and users of other smartphone systems can download a mobile version at http://m.tva.com.


2011 Spring Sportfish Survey

For anglers whose preferred waters include the Tennessee River system, it’s a great source of information on the status of black bass and crappie populations. The results of TVA’s 2011 spring sportfish survey are in, and an overview of the findings provides a useful look at fish abundance, condition, and general health.

image of nottley spilling

TVA fisheries biologists assess each fish’s condition, including factors such as
its weight relative to its length.

From March through May, crews conducted sampling on eight main-stem and four tributary reservoirs. The approach is much the same for every reservoir, but the number of sampling sites varies with the size of the waterbody. Sampling at each location consists of a dozen 30-minute electrofishing runs covering various habitat types. After being temporarily stunned, the fish float to the surface, where they are collected by TVA crews. They are weighed, measured, checked for disease and/or parasites, and are then released unharmed.

The survey targets sought-after species such as largemouth, smallmouth, and spotted bass—as well as both black and white crappie.

According to TVA Fisheries Biologist John Justice, tracking the numbers and condition of these “apex predators” reveals more than just how those specific populations are doing. “They’re at the top of the reservoir food chain,” he explains, “so we can make some general assumptions about other species in the ecosystem. If the apex predators are doing well, the fish that support them are doing well also.”

Justice and his colleagues calculate a “catch rate,” which factors in the number of fish collected per unit of time/effort. “We like to see a fish a minute,” he says, “and our 2011 catch rate was 57.2, averaging all the sampling we did on both main-stem and tribututary reservoirs. Pretty much textbook perfect, and—given weather conditions during the sampling period—well within where it should be.” 

Complete survey results will be available on TVA’s website by late summer. Meanwhile, here are just a few highlights:

  • Chickamauga and Guntersville reservoirs had the most largemouth bass five pounds and over. The largest fish in this year’s survey weighed in at 8.9 pounds, and was collected from the Harrison Bay area of Chickamauga.
  • Nickajack Reservoir recorded its highest catch rate (75.2 fish per hour) to date, and also had the highest average weight (2.3 pounds) ever recorded—system wide—for black bass over 10 inches.
  • Wheeler Reservoir had its highest number of three- and four-pound bass since the survey began back in 2000.
  • The greatest number of Smallmouth bass were collected from Pickwick Reservoir, Parksville Reservoir had the most spotted bass, Fort Loudoun had the most white crappie, and the most black crappie were collected from Chickamauga. 

Results of the annual survey contribute to TVA’s power plant monitoring and are also used by State resource management agencies to protect and improve fisheries in the Tennessee Valley.

They’re also a confirmation of sorts, says Justice: “It’s always good to verify that these populations are doing well. Among other things, that tells us that TVA operations continue to support a healthy sport fishery.”

image of nottley spilling

As in past years, TVA allowed members of the public to join the sampling crews as observers during the electrofishing runs and the associated work-ups. During the 2011 Spring Sportfish Survey, 144 individuals accompanied the crews, one of the highest public participation levels since the survey’s inception.


Get more information on TVA.com

The links below will take you to reservoir-related information on TVA’s website.

TVA’s reservoir operating policy:  Learn how TVA manages the flow of water through the Tennessee River system to provide navigation, flood damage reduction, power supply, water quality, water supply, recreation, and other benefits.

Reservoir information:  Get detailed information about individual reservoirs, including observed and predicted elevations and releases at TVA dams, reservoir operating guides, water quality improvements, fish population survey results, and more.

Rainfall and stream flows: Get the latest information on daily rainfall and stream flows across the Valley.

Recreation release schedules: View the 2011 schedule for water releases for rafting, kayaking, and canoeing below these TVA dams:  Apalachia, Ocoee No. 1, Ocoee No. 2, Ocoee No. 3, Norris, Watauga/Wilbur, Upper Bear Creek and Tims Ford.

Map of TVA reservoirs and power plants: Our interactive map is your guide to the entire TVA power system, including fossil and nuclear plants, dams and reservoirs, and visitor centers. You’ll find interesting facts about each facility and learn how they work together for the purposes of power supply, river management, and economic development.

Water supply FAQs: Get answers to frequently asked questions about obtaining a water intake permit, improving water quality around intakes, inter-basin transfers, and more.

Dangerous areas around TVA dams: If you like fishing or enjoy swimming and boating on TVA-managed reservoirs, you need to be aware of the possible hazards around dams, locks, and powerhouses.

How to lock through: Find out what you need to do to safely approach a navigation lock, secure your boat in the lock chamber, and exit the lock.

Reservoir health ratings: See the latest monitoring results for TVA-managed reservoirs.

Campgrounds and day-use areas: Get information here about campground fees and amenities as well as picnic pavilion reservations.

TVAkids.com: TVA’s got a Web site just for kids Learn about how TVA makes electricity, reduces flood damage, protects wildlife, and more. There’s a section for teachers, too.

TVA Heritage: Read about the people who founded TVA, shaped its purpose, and built its power plants. TVA Heritage offers fascinating glimpses of the agency’s history.

Get more information by phone
For the latest information on reservoir elevations and stream flows, call TVA’s Reservoir Information Line from a touch-tone phone:

  • From Knoxville, TN:  865-632-2264
  • From Chattanooga, TN:  423-751-2264
  • From Muscle Shoals, AL:  256-386-2264
  • From all other locations:  800-238-2264 (toll-free)

For answers to questions on how your reservoir is operated, call TVA River Operations at 865-632-6065.

For answers to questions about recreation, permitting procedures, reservoir land management plans, and other environmental issues, call TVA’s Environmental Information Center at 1-800-882-5263.