Elaine Meinel Supkis
A major dam in Kentucky is about to collapse. The Wolf Creek dam was foolishly built on limestone/karst which dissolves in water. All previous attempts at 'fixing' this has now failed and if the dam blows out, Nashville, TN, will have a New Orleans flood event.
The Commander of the U.S. Army Corps of Engineers, Nashville District, announced plans Monday to lower the lake level at Lake Cumberland (Wolf Creek Dam), in Russell County, Ky., effective immediately to 680 feet, in response to Corps and independent studies that have classified the dam as being at “high risk” for structural failure.
Normal pool levels are 723 feet in the summer and 690 feet in the winter. Dam safety experts will continually monitor conditions at Wolf Creek and further reductions may be necessary depending on the effect that lower lake levels have on the dam. Lowering the lake level will reduce the risk of dam failure by decreasing water pressure on the dam and reducing foundation seepage.
These changes are in concert with ongoing rehabilitation plans at Wolf Creek that address the problem of seepage through the foundation of the dam.
Click here to enlarge picture of Wolf Creek Dam.
Like the little Dutch Boy of yore, they basically are sticking their collective fingers in this massive dike. Namely, this is the biggest dam east of the Mississippi River! No small matter. Click here to see some of the astonishing pictures of the Johnstown flood of 1889. The Johnstown flood which was caused by the collapse of a poorly-engineered dam, so traumatized Victorians, they still referred to it in cartoons, books and songs well into the 1940s. My mother's godmother who lived to be 104 years old told me about it when I was a child, she was in her 20's when it happened. I remember seeing cartoons where characters try desperately to save small orphans from that flood. It was on par with the Titanic back then.
Click here to enlarge image of Johnstown after the terrible 1889 flood.
The Wolf Creek Dam could replicate the horrors of Johnstown.
The Army Corps of Engineers has identified Wolf Creek Dam as one of the highest risk dams in the Corps Inventory.
&hearts The Corps will request full funding to accelerate construction of the remedial project. Nashville District has already awarded the first construction contract for the grouting program and grouting is underway.
Click on image to see satellite photo of this artificial lake system.
Right now they are injecting grout like we put around tiles, into the base of this huge dam. The chances of this working is around zero. All we need is one catastrophic storm. The most likely being a hurricane. I know up here in my own mountains, the remnants of hurricanes can cause terrific floods. The steep mountainsides of the Appalachians are very prone to flooding. The Cumberland River has many dams along its great length. If this, one of the biggest and also at the head of the waters, breaks, it will probably destroy other dams below.
Flooding on the river remained a problem. Under the Flood Control Act of 1938, Corps projects were given a third purpose – flood control. Under this Act, the Nashville District investigated six reservoir sites along the Cumberland and its tributaries.
This led to the choice of Wolf Creek Project in KY for immediate construction in 1941. Congress also authorized construction of Center Hill and Dale Hollow Dams in Tennessee. Just three months after the Wolf Creek groundbreaking ceremony came the Japanese attack on Pearl Harbor and the start of World War II for the U.S. Congress directed that the construction of Wolf Creek Dam be expedited to furnish power for southeastern war industries.
It is interesting that attempts at stopping floods usually involve building systems that will, in a catastrophic storm, make things infinitely worse. There is no rainstorm that can best a dam collapse. For example, if New Orleans was build with an eye for the actual lay of the land, no one would build in dangerous places. But since the Army Corps of Engineers berthed the Mississippi with levees, people build right next to them, heedlessly and stupidly.
No one tried to stop this and all it took was one very strong storm and it all came tumbling down in a terrible wall of water that killed thousands of people. We still are dealing with the displaced population and people are already drifting in, reestablishing homes on the floodplains.
It is the carbon dioxide in rain water which causes limestone to dissolve. In fact, as rain falls, relatively little carbon dioxide dissolves but as the water percolates through the ground it dissolves more carbon dioxide from the roots of plants. The carbon dioxide solution then causes the insoluble calcium carbonate to react as forming calcium hyrogencarbonate (bicarbonate). (Most children will have heard about sodium bicarbonate [bicarb]).
Children may need some convincing that limestone will dissolve in water containing carbon dioxide. After all, it doesn't seem to dissolve in distilled water, which we've just said contains carbon dioxide. Does it dissolve in sparkling water? The easiest way to show them is to take lime water, calcium hydroxide solution. They all know it goes milky with carbon dioxide but probably don't realise this milkiness is due to the formation of insoluble calcium carbonate. (The particles of calcium carbonate are so fine they don't easily settle out. Usually, they are fine enough to pass through most school filters papers.)
However, if you continue to pass carbon dioxide through the mixture, ie through a suspension of calcium carbonate in water, it slowly dissolves.
It is worse: we have acid rain and indeed, a major coal-burning power plant fueling all those airconditioners, is right on this river! And the other matter: excess C02 is bonding with the limestone! This irresistable process wasn't a mystery 50 years ago. Even a child back then knew about these things. I used to play with their children's chemistry sets and we dissolved rocks and did other amusing things with the simple chemicals.
It is most amusing that the geologists beg the state to curb building on limestone. They point out the biggest cave complexes in America are in the same region this collapsing dam is in and they bemoan the fact that the Army Corps of Engineers didn't check out the facts with real geologists. They gloomily note that even if warned, builders pooh-pooh them and build anyway. They even illustrate housing disasters when a hole suddenly opens without warning.
When I was a child (and I still do this) I loved to dam things. We all did this. We would erect elaborate dams only the storms in Tucson can be very violent with sudden dumps of water in great volume and our dams would get blown away. Even if they weren't, we noticed that they would degrade over time, a sure sign of this is for water to pool at the base. The base weakens, the center sags and then it overflows.
The fact that water is now turning the ground under this dam into swiss cheese can't be evaded, if one stabilizes it temporarily, this is not a real solution, it is a patch. The concept of these dams, situating them and dealing with dam collapses is part of being an engineer or geologist. Just as builders must pay attention to the foundation of a building, dam builders must evaluate the very earth the dam will sit upon. Ignoring this is folly.
Just like vacationers demanded the Federal Government remove the roadblocks to Mt. St. Helen's three weeks before it blew up and killed anyone nearby, so it is here: the vacation people will show up in four months and they will be furious if the water table is 30' lower! They will demand the level be raised and the government will yield, as usual.
And we should remember, the Johnstown tragedy was due entirely to the rich industrialists in Pittsburgh, the tycoons of laissez unfaire. They wanted to have a lot of fish in an artificial lake for their private, secretive club!