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November Reservoir System Update
Tennessee Valley Authority (TVA)
Posted: 11/1/2010
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Eastern Valley Rainfall |
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Month |
Observed rainfall |
Normal rainfall |
Percent of normal |
January |
4.51 |
4.6 |
98 |
February |
2.68 |
4.23 |
63 |
March |
2.79 |
4.82 |
58 |
April |
2.69 |
4.17 |
65 |
May |
4.50 |
4.23 |
106 |
June |
2.91 |
4.28 |
70 |
July |
3.96 |
4.97 |
80 |
August |
4.01 |
4.28 |
94 |
September |
3.68 |
3.38 |
109 |
October |
2.89 |
2.99 |
97 |
Total |
34.63 |
42.10 |
82 |
Reservoir elevations
The elevations of tributary storage reservoirs gradually dropped through the month of October as TVA continued the annual drawdown to winter flood-damage-reduction levels. Most reservoirs were at expected levels on Nov. 1, ranging from an average of 14 feet above Jan. 1 target levels on Douglas, Fontana, Hiwassee, and Tims Ford to an average of four feet above Jan. 1 target levels on South Holston, Cherokee, Norris, Chatuge, Nottely, and Normandy.
As in previous months, Watauga Reservoir was the exception. It fell below its winter flood-damage reduction level the end of August because there wasn’t enough rain in the surrounding watershed to compensate for the water released to meet downstream flow requirements. Because Watauga is still below its winter flood-guide elevation, TVA is continuing to limit releases to conserve water in Watauga, which may result in some increase in the reservoir’s elevation depending on local rainfall.
Blue Ridge Reservoir is also a special case. TVA began a deep drawdown on Blue Ridge in mid-July. The reservoir is being held at an elevation between 1620 and 1630 feet above sea level—compared to its normal winter flood-damage-reduction level of 1668—as part of a project to rehabilitate the 79-year-old dam. Get an update on this project below.
Reservoirs along the main Tennessee River—Fort Loudoun, Watts Bar, Chickamauga, Nickajack, Guntersville, Wheeler, Wilson, Pickwick, and Kentucky—were all within their normal operating ranges on Nov. 1.
Tributary Reservoir Elevations¹ |
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Reservoir |
Nov. 1, 2010 |
Jan. 1 |
South Holston |
1712.1 |
1708 |
Watauga |
1947.7 |
1952 |
Cherokee |
1050.7 |
1045 |
Douglas |
969.5 |
954 |
Fontana |
1670.9 |
1653 |
Norris |
1004.7 |
1000 |
Chatuge |
1920.1 |
1918 |
Nottely |
1766.3 |
1762 |
Hiwassee |
1497.4 |
1485 |
Blue Ridge |
1625.1 |
1668 |
Tims Ford |
885.8 |
873.1 |
Normandy |
868.5 |
864 |
1 Water elevation at the dam in feet above mean sea level
2 Flood-guide elevations show the amount of storage allocated for flood damage reduction during different times of the year. The amount of storage varies with the potential flood threat. Flood-guide elevations are lowest from Jan. 1 through mid March because winter storms are generally larger, occur more frequently, and produce more runoff. Flood-guide elevations increase between mid-March and June 1 as the risk of flooding decreases. They are highest from June 1 through Labor Day to support summer reservoir recreation. After Labor Day, TVA begins the unrestricted drawdown to Jan. 1 flood-guide elevations.
Reservoir operations
From September through
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