The U.S. Army Corps of Engineers, Nashville District, announced today that drought conditions in the Cumberland River Basin will lead to modified operations of Cumberland River Basin reservoirs in order to reduce, to the extent possible, the adverse impacts along the river.
Adverse impacts will affect project purposes all along the Cumberland River from Laurel River Lake to Lake Barkley. There will be adverse impacts to project purposes including: recreation, hydropower, navigation, water quality, and water supply as well as to fisheries along the Cumberland River and fossil fuel power plants along the Cumberland River.
The drought conditions being experienced in the Cumberland River Basin are due to lack of precipitation during early 2007. The impacts of the drought will be greater than normal due to operating restrictions at Lake Cumberland and Center Hill Lakes. Wolf Creek and Center Hill Dams are being operated at lower levels after being classified as high risk dams. Both dams have major rehabilitation projects ongoing.
“We are seeing conditions that we would not normally see until the end of August in a typically dry year,” said Bob Sneed, Chief of the Water Management Section, Nashville District. “I am also concerned about the low dissolved oxygen levels (DO) at some of our reservoirs. For instance, Old Hickory Lake is seeing the lowest DO levels since 1988.”
Fish kills are possible if water temperatures in the Cumberland River continue to rise and the dissolved oxygen levels continue to drop. Warmer water puts stress on fish over time and then the lower dissolved oxygen rates make the water uninhabitable for fish, according to Sneed.
The Nashville District is taking every action it can to provide water for water supply intakes, to protect the public safety of the recreational user, to maintain the navigation channel, to maintain the fisheries along the Cumberland River and to maintain operations of fossil fuel power plants along the Cumberland River. The operation of the Cumberland River Basin will be modified to the extent possible to mitigate for the drought conditions.
According to Bill Barron, chief of the Hydrology and Hydraulics Branch, Nashville District, many actions that have already been taken include: asking Eastern Kentucky Power to run only minimum hydropower releases at Laurel River Lake; pulsing of hydropower generation at Wolf Creek Dam every 6 hours to keep water supply intakes covered at Burkesville, KY and Cumberland County, KY and to keep water temperature below the dam low. The Corps is also pulsing at Center Hill Dam every 12 hours for similar reasons; filling of Dale Hollow to higher than normal elevations to provide for extra storage; filling of Cordell Hull, Old Hickory, and Cheatham Lakes to slightly higher levels for emergency mitigations; spilling and partial hydropower generation at Old Hickory Dam to improve dissolved oxygen and to provide a “window of opportunity” for navigation.
In addition the Corps is spilling at Cheatham Dam to try to keep water temperatures low and to assist navigation; removing tail water restrictions at Lake Barkley and adjusting releases to minimum flow used only as flow is needed for navigation, and increased monitoring of the water temperature and dissolved oxygen levels along the Cumberland River. Future actions may include: discharging more water at tributary projects (Dale Hollow Lake, Center Hill Lake and J. Percy Priest Lake) thereby reducing their water levels below normal.
The good news is the cold water fisheries below Wolf Creek and Center Hill Dams at present are doing well because of the amount of cold water being released now, but if water temperatures rise these fisheries may be in danger. “I have been told the trout fishing is great below Wolf Creek Dam and in the Caney Fork River below Center Hill Dam,” said Sneed.
The operating objectives for the Cumberland River Basin in order of priority (highest to lowest) are: water supply, water quality, navigation, hydropower, and recreation. These objectives are also project purposes and ranked in this order with public safety as the number one priority.
The pool levels in tributary projects (Dale Hollow Lake, Center Hill Lake and J. Percy Priest Lake) will be lowered as required to maintain the operating objectives of the Cumberland River Basin. As the drought continues, recreational users will see gradually lower water levels.
As the lake levels are gradually lowered, rocks and other obstacles may be exposed and become hazards for boaters and other recreational users. Also, certain areas of lakes may not be accessible due to the low water.
Other concerns are maintaining navigation along the Cumberland River and the operation of fossil fuel power plants on the River. The Corps is working with the navigation industry to provide “windows of opportunity” where there will be enough flow for navigation. The Corps is also working with the Sherman Cooper Power Plant, the Gallatin Steam Plant and the Cumberland City Power Plant to lessen impacts to their operations.
“We will be trying to balance the operating objectives to best utilize the water we have in the Cumberland River Basin,” said Barron, “but we know there will be adverse impacts to all of the objectives this year. In a normal year, we have enough water that we only have to juggle two or three objectives, say water quality, navigation and hydropower, but this year we are juggling all five.”
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