"Lake level to be low through summer, perhaps into summer 2008
It won’t be officially announced until Monday morning (Jan 22), but it appears it is going to be a low-water summer for boaters and visitors to giant Lake Cumberland. Marina operators and area officials have been notified in advance that the U.S. Army Corps of Engineers (COE) is planning to reduce the level of the lake to 680 feet above sea level through September, and possibly into October – or perhaps for as long as 18 months, which would put the lower levels into the summer of 2008.
This would be about 45 feet below the tree line, and about 10 feet lower than the current level of the lake, which is now at its usual January winter low level. The COE annually reduces the level during the fall and early winter to enable it to catch usual heavy late winter / early spring rainfalls, which usually bring the lake back to its “summer pool.”
The move is prompted by the serious “seepage” of water through the limestone bedrock under the dam that was discovered and announced in 2005. A planned $300+ million retrofit of the nearly mile-long earthfill portion of the dam – by inserting a huge concrete “diaphragm” inside the rocky portion of the dam – is currently in beginning stages.
The COE had previously announced they planned to keep the level of the lake lower than normal during the spring flood seasons to reduce stress on the 57-year-old dam, but would be cautiously allowing the lake to return to normal summer levels. However, it appears that engineers have growing concerns about the stability of the dam, which has partially led to the probable very low summer levels.
Word is that some of the engineers are not comfortable with even the 680 foot level, and would prefer the water be lower to reduce stress on the structure. We understand that the COE plan to reduce the level to 680 feet within the next couple of weeks, then monitor the stress levels within the dam structure. If satisfactory after that, the level would be maintained during the first grouting work and with further checks the lake could be allowed to rise a little. However, if the pressure is still at an unsatisfactory level, there could be a reevaluation to lower the lake even further than 680 feet to reduce the pressure on the structure and its porous bedrock base.
While lower than normal, a lake level of 680 feet is not overly unusual, just a few feet lower than many wintertime lows over the life of the lake. However, that level during the spring and summer tourism season is extremely rare. The only previous time the lake was very low in the warm months was in the mid-1970s when work on the dam for a previous – and very serious – leak was underway. During that period, the lowest level was 677.85 feet, recorded on Feb. 9, 1977. A few years later, on Jan. 27, 1981, the lake was allowed to fall to the second lowest-ever level of 675.10 feet.
(The lowest all-time level of the lake occurred just 3 years after the lake filled, in Nov. 1954, when during a period of extreme drought the lake’s level fell to 665.11 feet above sea level.)
The expected low levels will have some effect on boaters’ ability to launch into the lake. Already the COE has announced that several of its launches will be too exposed to be used. At some of the lake’s 11 commercial marinas and docks there will have to be some major adjustments to mooring, though at 680 feet nearly all should still have usable launches.
Even at an unusual summertime low level of 680 feet, Lake Cumberland is still a major body of water with a huge surface area for recreational uses. It would still be one of the largest and deepest man-made lakes in the U.S. At its "normal summer pool" of 723 feet, the amount of water contained in Lake Cumberland is enough to cover the entire state of Kentucky 3 inches deep.
The COE plans a news release around 8 a.m. on Monday morning, Jan 22, to explain their plans.
LINK: COLLECTION OF NEWS ARTICLES ON DAM SEEPAGE PROBLEM"