A $300 million, seven-year project to shore up the dam, which was built above caves and an eroding limestone base, is about to begin.
The limestone formations, called karst, are an issue with any structure in this area that holds back water, said Larry Weber, a geologist with Geosciences Design Group and national president of the American Institute of Professional Geologists.
"We're talking about conduits and holes in the bedrocks," he said. "That's a natural channel for water to bypass whatever structure you're trying to design."
If the Wolf Creek Dam were to give way while water levels are high in Lake Cumberland, the flood could sweep trailers, bridges, propane tanks and a host of other items downstream, adding to the damage.
Oh...MY...Lord!!!! I saw this post and creaky bits of my brain started rubbing together...Dug around in my detritus, and found 3 pages of engineering critique on the Wolf Creek Dam in "A Dam Site Worse than Teton" by my late friend Don Rimbach. (Teton Dam was a poorly constructed Western dam which failed catastrophically on June 5, 1976, literally wiping out about 80% of the structures in downstream Rexburg, ID. Astonishingly, only 14 fatalities resulted from the draining of the almost 300,000 acre foot lake over about 12 hours. )
According to his booklet, Wolf Creek was built on caves with 12' high air passage and mudfill passage up to 35 ft high in the 1940s. (Under hydraulic pressure, and assuming an outlet, a mud fill isn't exactly the same thing as rock.) After severe leakage in 1967, and the beginnings of the collapse of the dam in early 1968 and Oct. 1973, over $100 million (in 1970s dollars) was sunk into repairs by 1977 --12X what it cost to build the dam originally. This was supposed to fix the dam for its foreseeable life. Now, we're 30 more years down the road, and they are going to fix it forever for $300 million. Oh...My....Lord!!!
My friend did this critique as part of his engineering argument against the Meramec Dam project, in which (mid-60s to its deauthorization in 1981) the same people, our lovely Army Corps, planned to build a major mainstem dam on the Meramec River, and planning to grout known cave and mudfilled passage in excess of 50' high in one of the abutments of that dam.
Man, if I lived downstream of the Wolf Creek dam, the heck with flood insurance. I think I'd move.
By the way... the second largest spring in Arkansas, Big Spring, is an artifact of Bull Shoals Dam. Yes, there was a spring there originally, but it was a small thing. Once the dam was built, water under height head pressure (stacked up behind the dam) found a way around it into an already existing conduit. This leak apparently does not threaten the integrity of that dam. But it is very interesting the 'spin' the Arkansas State Parks puts on this. There is an Arkansas State Park at Bull Shoals, which contains the spring. About a month ago I heard a presentation by a very nice young lady explaining what a wonderful resource this spring was, and that tourists loved ot look at it , etc. "It's a feature...not a bug."
If any Nashvillans would like copies of the three pages of this document, let me know. If there is enough interest, I will scan them and post them as .pdfs on the web.
Here are another couple of links to articles concerning Kentucky's leaking Wolf Creek Dam.
Monday, 01/22/07 Wolf Creek Dam reclassified as 'high risk;' water level to be dropped at Lake Cumberland By ANNE PAINE Staff Writer
The leaky Wolf Creek Dam in Kentucky – upstream of Nashville on the Cumberland River -- has been classified as a “high risk” for breaking, and federal authorities will drop the water level at Lake Cumberland in response, the U.S. Army Corps of Engineers announced this morning.
"A high level of risk does exist," Lt. Col. Steven J. Roemhildt, commander of the Corps’ Nashville District, said this morning in a printed statement.
"Reducing lake levels lowers pressure on the dam and pumping grout into the ground lessens erosion, both of which immediately reduce risk."
The Corps has identified Wolf Creek Dam as one of the highest-risk dams the Corps manages.
Feds fear a dam break in Ky. and Tenn. By ROGER ALFORD, Associated Press Writer
FRANKFORT, Ky. - Fearing a dam break that could cause catastrophic flooding in Kentucky and Tennessee, the Army Corps of Engineers began lowering the water level on Lake Cumberland on Monday.
The measure was aimed at reducing pressure on the weakened 240-foot-high dam, said Lt. Col. Steven J. Roemhildt, commander of the Corps of Engineers' Nashville office.
"We must take this emergency action to reduce risk to the public and to the dam itself," he said in a statement.
If the Wolf Creek Dam, which is nearly a mile long, were to break, flooding in communities downstream along the Cumberland River could kill people and cause an estimated $3.4 billion in damage, Roemhildt said. Cities along the Cumberland include Nashville, Tenn.
Post by Tony Anders on Jan 23, 2007 19:14:58 GMT -5
1968-1970: Emergency grouting of Wolf Creek Dam is credited with saving the dam, but does not solve the problem, cavernous limestone bedrock below the dam.
2006: Preliminary phase for plans to pour a new grout curtain into bedrock 25 feet below Cumberland Dam to prevent failure of dam. The new waterpark in Somerset is damaged by sinkhole collapse shortly after the park is opened.
I wonder why it took them so long to try to fix the problem, if they knew about it in the 70's
Post by Tony Anders on Jan 23, 2007 21:33:24 GMT -5
Another link from local paper here...
Corps of Engineers’ Roemhildt says Wolf Creek Dam is high risk By BILL MARDIS, Editor Emeritus Commonwealth Journal
“I am very concerned about Wolf Creek Dam ... that’s the reason it’s in the high-risk category.”
Lt. Colonel Steven J. Roemhildt, commander of the U.S. Army Corps of Engineers’ Nashville District, made the unsettling assessment to the Commonwealth Journal yesterday afternoon. His comment followed announcement by the Corps that Wolf Creek Dam is at a high risk of structural failure.
To relieve water pressure on the ailing dam, the Corps announced yesterday that the lake level will be lowered immediately to 43 feet below the tree line to relieve pressure on the dam.
Brigadier General Bruce Berwick, commander general of the Great Lakes and Ohio River Division of the Corps, is the chief decision-maker for the water level. Roemhildt said he made recommendations to Berwick and “ ... totally supports his decision.”
Roemhildt said there are no sinkholes or muddy water in the tailrace as when the dam was first discovered leaking in 1968. However, he said piezometers (pressure reading gauges) and wet spots indicate seepage throughout the entire length of the dam, including beneath the concrete section.
An emergency grouting program has been initiated to stop the seepage and fill any possible erosion cavities, Roemhildt said. Grouting is forcing liquid concrete into the earthen section of the dam.
A Canadian firm, Advan-ced Construction Techniques LTD, has been given a $51 million contract to build grout curtains on both sides of a proposed concrete diaphragm. This work apparently will be expedited.
Roemhildt said a contract will be let in December to insert another diaphragm into the dam.
The diaphragm will extend through the entire earthen section of the dam and about 100 feet into the bedrock. A diaphragm extending some 25 feet into the bedrock was inserted into the dam in the 1970s after a serious leak was discovered in the late 1960s.
Corps engineers have apparently known since March 2005 that the dam was leaking again. The public announcement of the problem and planned $309 million rehabilitation of the dam was made in August 2005.
The revelation had a familiar ring. A muddy discoloration of water in the dam’s tailrace in 1967 warned engineers that materials were being washed from beneath the structure. A sinkhole was discovered near the toe of the dam on March 13, 1968. The pit grew to 10 feet in diameter and eight feet deep during the next two days. Another sinkhole developed in late April of that year about 75 feet from the first sinkhole.
After a dozen years and $103 million spent, the original diaphragm wall was completed. Engineers thought at the time that the problem was solved.
Roemhildt said Wolf Creek Dam “can be fixed.” He said the Corps will seek international for a contractor to do the job. “There are very few companies that can do this kind of work,” he said.
Corps studies have indicated a catastrophic failure of Wolf Creek Dam would inflict $3.4 billion in damages downstream. A Tennessee newspaper estimated that 10,000 structures in Nashville would be inundated if the dam gave way. Several other communities in Kentucky and Tennessee would be in harm’s way.
Wolf Creek Dam is 158 feet high and 5,738 feet long. It impounds 63,000 acres of water with 1,255 miles of shoreline.
They likely knew they had a problem from the very beginning when the lake filled. If most dams are going to leak, they do so as soon as standard pool levels are reached. The question is: What's the percentage in spending 500 million dollars plus (over 50 years) to fix a $15 million dollar dam? How about just giving up and starting over? They did this at the Hales Bar Dam:
Post by Sharon Faulkner on Jan 28, 2007 17:59:16 GMT -5
Seems like the Lake Cumberland Dam problems are still a hot topic. Here is a new article citing some sources who believe the water level should be lowered more than previously recommended. -----------------------------------
Experts disagree over lake level
Lake Cumberland drawdown enough for dam safety, corps says. But others assert more should be drained. By James Bruggers firstname.lastname@example.org January 28, 2007
An outside group of engineers recommended a much more drastic lowering of Lake Cumberland than the 10-foot drop the Army Corps of Engineers began last week.
Those experts backed lowering the lake level an additional 30 to 70 feet to take pressure off the leaky Wolf Creek Dam as a safety precaution, according to a senior corps official.
But David Hendrix, manager of a project to fix the dam, said corps officials decided that an extreme drawdown wasn't necessary. They believed they could protect people who live downstream by lowering the water level to 680 feet above sea level, he said.
Corps officials said the dam, which has been plagued with problems for 40 years, is not about to collapse. And if it were to begin to fail, there would be warning signs, giving people time to evacuate "and prevent a loss of life," Hendrix said.
Corps spokesman Bill Peoples said the decision to lower the lake was prompted by an agency risk assessment in 2005 and the outside experts' review of it, combined with new methods for evaluating risk.
Hendrix said the action reduces the potential damage that would have resulted from a flood if the dam had failed while the lake was full. That worst-case scenario could have caused an estimated $3 billion in damage, much of it in Nashville, 280 miles down the Cumberland River from the dam.
With the lake at the 680-foot level, flooding in Nashville would be more manageable, said Amanda Sluss, a spokeswoman for the mayor's office of emergency management. The river would not likely reach street level downtown, but there would be moderate flooding in tributaries in Davidson County, she said.
I noticed the article actually mentioned the word Karst! This is a great improvement over just a few years ago when they had no clue what the word meant! Cool!
Karst to an engineer means: " Keep them yhar concrete trucks coming Billy Bob, and we'll get that big hole down cheer filled yet!"
Only problem is: they fill this big hole, and then the water finds another big hole over yonder. There is also a mindset that unless there is a true void (not a clay filled void) there is no problem. They've never heard of piping caused by stacking too much hydraulic head behind a big tunnel filled with dirt. It will hold. For a while. Then bingo-- "hey, ladies and gents we have a new spring, and it's flowing bass and crappie." A genuwine tourist miracle!
Post by Brian Roebuck on Jan 28, 2007 20:45:52 GMT -5
Yeah, I was just remarking to Lynn that all TVA dams are built in Karst terrain. The Tennessee valley is Karst! Lots of dams around here are leaky too. They just are located downstream of Nashville and don't have the political spin that Wolf Creek Dam does. Still it would be newsworthy if any of them burst!
Where's my concrete mixer/ (I am an engineer ya know)
Brian Roebuck NSS 34626 RL (FE) ----- Caving is far too serious to be taken seriously.
We've got a good one here called Clearwater Dam, holding back Lake Clearwater in SE/SC Missouri, near the town of Piedmont. It says it is a dam, but it is actually a stormwater retention device. It's holding back silt and sediment, and slowly allowing water to leak downstream through a number of holes below the dam, and it is one of those 'smack the groundhog or prairie dog' games to try to get them filled. Clearwater is much smaller than the Wolf Creek situation, and none of the holes are imminently threatening the dam footing (at least this week).
Brian, being an engineer is a dirty job, but someone has to do it. Believe me, I know enough geological and geotechnical engineers to know the ribbing which goes back and forth between them and the academic and regulatory geologists. (Try being on a schoolbus with the occupants divided half and half!) I have no problems with most engineers. Just the few who think they are GOD, and, in the words of a famous cartoonist who fought tooth and nail against the damming of the Buffalo River in Arkansas (the karst area which later became the Buffalo National Scenic River) who drew a lake shaped like the state of Arkansas and captioned it: "God would have done it this way, if he had only had the money."
Nashville and it's surrounding communities sit below two dams the U.S. Army Corps of Engineers has said are at a high risk of failure, Center Hill Dam and Wolf Creek Dam in Kentucky .
Now, people living along the Cumberland River want to know if they'll be safe when and if either dam fails.
To alleviate some of the unknown, those living along the river want to see maps that show probable flood areas, if the dam were to fail. The U.S. Army Corps of Engineers was reluctant to release the information, due to homeland security issues....
The agency is now changing its' tune and the potentially life-saving maps are expected to released to local libraries next week. Due to the detail and the large size of the maps, they will not be available online. Copies, for viewing only, will be placed in Mid-State libraries.
Post by Sharon Faulkner on Jan 31, 2007 21:01:50 GMT -5
The Weather Channel had a brief program on the Wolf Creek Dam this evening. Only 15 minutes or so, but they had some good video of the Dam and a map showing the projected flooding of Nashville. According to the program, Nashville will flood to 30 feet above flood stage and the amount of damage would rival that wrought by Hurricane Katrina in New Orleans.
If I lived in Nashville, I'd probably be in favor of lowering the level of Lake Cumberland a little more.