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May 4, 2010

In this issue:
Rain and runoff
Reservoir elevations
Reservoir operations
In answer to your question about water temperatures
Tennessee River lock closures
What's going on at the Norris weir?
2010 recreation release schedules

More TVA information

TVA provides monthly updates on the operation of TVA-managed reservoirs by e-mail. To sign up for future updates, provide feedback, change your e-mail address, or have your address removed from this distribution list, please send an e-mail request to reservoirupdate@tva.com.


Rain and runoff

The western part of the Tennessee Valley was hit by heavy rains May 1 and 2. Some areas received as much as 15 inches in this two-day period. But rainfall in the eastern Valley was relatively light, averaging from 1-3 inches. Rainfall in the eastern Valley was below normal in February, March, and April, as the chart below shows.


Observed rainfall

Normal rainfall

Percent of normal

















Runoff (the amount of water that reaches the river system when it rains instead of being absorbed into the ground) is currently 95 percent of normal in the eastern Valley.


Reservoir elevations

The elevations of TVA-managed reservoirs increased over the weekend of May 1-2 as an average of 3.5 inches of rain fell across the Valley and TVA stored water in tributary and upper-main river reservoirs to minimize the impacts of high flows on the lower end of the Tennessee River system. At midnight, May 4, most tributary reservoirs were at or near their flood guide elevations with the exceptions of South Holston, Cherokee, and Norris, which averaged about four feet below their flood guide elevations.  Most main-river reservoirs were within or being drawn back to their normal operating zones. Kentucky Reservoir was continuing to rise.  Near-record elevations are projected at Kentucky as TVA continues to hold back water to reduce flooding on the Ohio River in conjunction with a flood control operation directed by the U.S. Army Corps of Engineers.

Tributary reservoir elevations¹


May 4, 2010
Observed Elevation

May 4
Flood Guide Elevation²

June 1
Flood Guide²

South Holston




































Blue Ridge




Tims Ford








¹Elevations above mean sea level
²Flood guide elevations show the amount of storage allocated for flood damage reduction during different times of the year. From June 1 through Labor Day, 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. During this period, reservoir levels fall below the flood guide only when rain and runoff are insufficient to meet flow requirements. 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

Since mid-March, TVA reservoir operations have focused on filling tributary storage reservoirs to June 1 target elevations while making sure there is enough water flowing through the river system to protect aquatic life and meet downstream water supply needs.

“Rainfall in the eastern Valley has been below normal since February, so we’ve only released the minimum amount of water needed to meet the flow commitments specified in our operating policy,” said Chuck Bach, TVA General Manager for River Scheduling.

Those flow commitments protect a range of uses—from aquatic habitat to municipal and industrial waste assimilation, power plant cooling, and whitewater recreation. TVA is generating hydroelectric power with the water released to meet its flow commitments, but no additional water is being released solely for the purpose of hydro generation.

TVA's conservative operating strategy, in combination with stored water from above-normal precipitation in late 2009, kept most tributary reservoirs near their target elevations through mid-April. Dry weather in late April caused a growing number of reservoirs to drop below their flood guide elevations. But the eastern Valley received an average of two inches of rain the weekend of May 1-2, which helped bring most of those reservoirs back to seasonal levels.

There are three exceptions, according to Bach. “Norris, Cherokee, and South Holston Reservoirs have missed out on most of the rain we’ve received in other parts of the eastern Valley. Consequently, they are not filling as fast as we’d like. We expect Norris to catch up in the next few days when the rain that fell in the upper end of the watershed reaches the reservoir.  But the Cherokee and South Holston watersheds didn’t get as much rain. We’ll hold on to every drop of water that we can in those reservoirs, but it will take significant local rainfall to bring them up to June 1 elevations on schedule.”

To track your reservoir's elevation in comparison to its flood guide level, go to TVA's Reservoir Information site. Choose a TVA-managed reservoir from the pull-down menu on the right-hand side of the page. Then, from the pull-down menu for “Type of Information,” select “Operating Guide,” then “View Info.”


In answer to your question about water temperatures

Where can I find information on water temperatures for TVA-managed reservoirs?
Water temperatures are of interest to many reservoir users, particularly anglers interested in planning a fishing trip. In the spring, surface or near-surface water temperatures can alert anglers to when and where the water has warmed enough to encourage fish to feed. Later in the summer, anglers in search of striped bass can use water temperatures to tell them how deep they'll need to fish in order to reach that cool, oxygen-rich zone where stripers like to congregate.

TVA's temperature monitoring is designed for operational purposes. It doesn't show temperature variations from day to day or from one part of the reservoir to another, which are important to anglers.

State fisheries management agencies are a better source for water temperature information. They monitor water temperatures very carefully because they are important to the health of the fisheries, and many share the data they collect on their Web sites, recognizing the benefit to anglers.

The Tennessee Wildlife Resource Agency, for example, provides online fishing reports that include surface water temperature information. (Look under “Related Topics” at the bottom of the page.) TWRA Region IV also offers summer water quality reports that include water temperatures at various depths for many East Tennessee reservoirs.

For information about surface water temperatures in other states, visit your state government Web site or try searching online. You'll find numerous marinas, as well as angler guides and commercial Web sites, geared toward outdoor recreation, which offer this type of information.


Tennessee River lock closures

The U.S. Army Corps of Engineers has scheduled the following lock closures on the Tennessee River in 2010:

Fort Loudoun Lock was closed to navigation traffic on April 20. It is scheduled to reopen on May 13.
Chickamauga Lock is scheduled for closure from July 20 through August 16.
Watts Bar Lock is scheduled for closure from October 12 through November 2.

These lock closures are for routine maintenance. Closure schedules are subject to change so be sure to check the Nashville District's Navigation Notices Web page for updates.

Melton Hill Lock also is scheduled for closure June 8 through June 29, but the closure will not impact recreation users since recreational lockages are only available by reservation on a limited number of pre-scheduled days. To check the recreation lockage schedule and to make or cancel a reservation, contact the Fort Loudoun lockmaster at 865-986-2762.

The U.S. Army Corps of Engineers is responsible for operating and maintaining locks on the Tennessee River; constructing new locks; and performing periodic channel inspections, maintenance dredging, and barge mooring maintenance. TVA provides navigation flows and power for lock operations, maintains roads and grounds, and constructs and maintains lock support facilities.


What's going on at the Norris weir?

Norris residents and anglers who like to fish the tailwater below Norris Dam may be wondering about the work taking place on the island located between the two sections of the weir. TVA is repairing a breach in the dike on the island. The dike helps prevent the water from eroding the island. By protecting the island, the dike also protects the stability of the weir, which is anchored to its edge.

TVA has closed a parking lot and a walkway near the area where the materials for the repair are being stored, but the work does not impact fishing or other recreational uses of the area. The repairs to the dike should be completed by the middle of June.

The Norris weir operates like a small dam, holding back some of the water when power is being generated, then slowly releasing it when generation stops. This maintains a constant flow of water as the weir pool drains, which helps to prevent the riverbed from drying out.

While the primary function of the Norris weir is to provide a steady release downstream, it also adds oxygen to the water as it cascades across the top of the weir. This is important because low-oxygen conditions can occur downstream of hydroelectric dams such as Norris, causing problems for fish and other aquatic life which depend on oxygen as much as creatures living on land do.

The Norris weir is one of many TVA projects designed to improve conditions for aquatic life in the tailwaters below its hydroelectric plants. Studies show that these improvements have benefited aquatic life in more than 300 miles of river and resulted in a dramatic increase in tailwater fishing, which aids local economies.

Find out what TVA is doing to improve water quality below other dams.


2010 recreation release schedules

A growing number of people are interested in tailwater recreation—whitewater rafting, canoeing, kayaking, and fishing in the area downstream of TVA dams. To support these recreation activities, TVA releases enough water from the upstream reservoir to keep the riverbed downstream of the dam from drying out between periods of power generation and provides scheduled releases so that paddlers and anglers will know when they can count on desired river conditions below eight TVA dams.

TVA began providing scheduled releases for whitewater recreation below Ocoee No. 2 Dam on April 17. (Typically, these releases begin in mid-March, but they were delayed this year due to a November 2009 rockslide which closed a section of Highway 64, eliminating access to the rafting put-in area.) Recreational releases resumed at Apalachia and Norris on May 1. Recreation releases are scheduled to begin at Ocoee No. 3 on May 15; at Tims Ford, Upper Bear Creek, and Watauga/Wilbur on May 29; and at Ocoee No. 1 on June 1.

Click here to see the complete 2010 recreation release schedules for these dams.


Get more information on TVA.com
The links below will take you to reservoir-related information on TVA’s Web site.

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.  To check reservoir information from your cell phone or other mobile device, go to http://m.tva.com.

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

Recreation release schedules:  View the 2010 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, 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 76-year 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.

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