These are notes that I am writing to help me learn our industrial history. They are my best understanding, but that does not mean they are a correct understanding.
Wednesday, August 11, 2021
Wolf Creek Dam and 270mw Hydropower on the Cumberland River
The length of this 258' high dam is 5,736', of which 1,796' is concrete. The reservoir is Lake Cumberland. The drainage area is 5,789 sq. mi. When full (elevation 760'), the length of the pools is 101 river miles and the length of the shoreline is 1,255 miles. The spillway crest is 723', the top of the gates is 760' and the top of the dam is 773'.
Elevation
Acres
kilo acre-feet
top of
760
63,530
2,094 (760-723)
flood pool
723
50,250
2,142 (723-673)
summer pool
673
35,820
1,853 (<673)
dead pool
The 270kw capacity consists of 6 units of 45mw each. Average yearly output is 800gwh. The powerplant can pass 9,800cfs and the spillway has a discharge capacity of 553,000cfs using 10 50'x37' tainter gates.
Their link to the "Safety Rehabilitation Project" is broke.
Pictured is the Wolf Creek Power Plant at Wolf Creek Dam in Jamestown, Ky.
It is the largest of U.S. Army Corps of Engineers Nashville District’s hydropower plants with six 45 KW generators capable of producing 270,000 KW of clean electricity.
The nine hydroelectric power plants in the Nashville District provide enough electricity to power about 287,000 homes annually. It would take about 1.4 million tons of coal to generate the same amount of electricity.
Additionally, it only takes a few minutes to put a hydroelectric unit online, versus hours for some other forms of generation.
The Nashville District salutes our Hydropower Team who works each day to operate and oversee hydropower in Cumberland River Basin.
The dam is the 25th largest dam in the US and the most monitored in the world. The Wolf Creek National Fish Hatchery is located at the base of the dam. "The Wolf Creek Dam area is one of the top fly fishing spots in the United States." [KentuckyTourism]
"Wolf Creek Dam is the 22nd largest dam in the United States....Lake Cumberland is 101 miles long and is one of the largest man-made lakes in the Nation." [LakeCumberlandVacation]
This dam is the major source of water during droughts in the river system.
energy "Only three dams sustain the desired Cumberland River flows through Barkley Dam during drought. Wolf Creek, Dale Hollow, and Center Hill Dams supply 65%, 15%, and 16%, respectively, of the total flow in the Cumberland River system during dry conditions. The ability of a project to contribute flow to the system is linked to the summer pool storage volume maintained at a Wolf Creek, Dale Hollow and Center Hill projects. " [The is more information from this reference below.]
Feb 22, 2019: "Elevation at Lake Cumberland is 746.05 feet above sea level as of noon Thursday. That is 23 feet above the tree line, inundating and closing many recreational areas. The current level is the highest observed since April 25, 1998 when the pool crested at 742.44 feet. A total of 47.4 percent of the flood control pool is currently being utilized. With the additional rainfall expected this week, reaching elevation 750 is possible. The pool of record is 751.69 set in May 1984. In the history of Wolf Creek Dam, which spans back to 1950, elevation 745 has been exceeded twice - 747.12 in April 1962 and the pool of record." The storage pool can hold 6.78" of rainfall runoff from the 5,789 sq.mi. watershed. The reservoir filled up in 1952. In the 1960s huge sinkholes and muddy water appeared. In the 1970s the USACE built a concrete wall in the earthen section 225' into the limestone base. It wasn't enough. During 2007-2014 a secant cutoff wall that was 75' deeper (300') was created using 50" holes placed so that the wall was at least 2' thick. Lake Cumberland was lowered 40' during the years of this construction. [somerset-kentucky] This is another big dam that had been built on a cave system (limestone). (The 1967 Nickajac Dam replaced the 1913 Hales Bar Dam because a new dam on good foundation rock was cheaper than trying to properly repair the old dam.)
"Under normal operations, summer pool elevation of 723 ft and is targeted in mid-May
and held until mid-June. The lake is then gradually drawn down to reach the targeted winter
pool elevation of 695 ft by January....Due to Lake Cumberland’s seasonal thermal stratification, hydropower releases are generally below the DO [dissolved oxygen] standard from mid-July until the lake destratifies in mid to late-November." The input to the turbine penstocks are fixed at a depth low enough that it draws water from a lower layer that is low in DO. In 2007, the Corps added gates that can release just 540cfs. of water. This creates a turbulent flow that aerates the water. Existing sluice gates can release up to 6,400cfs if more turbulent water is needed. They also modified three of the turbines to improve DO levels in the release water. The modifications added 1.5mg/l, but the water quality standard of 6.0mg/l was still not achieved. Water released by the bypass gates is lost revenue ranging from $600k to $1.4m per year. Originally, the Cumberland River was a warm water river. The dam turned it into a cold water river. In fact, they exploited making a cold river in Tennessee by building a trout fish hatchery and starting a fly-fishing tourist industry. Also, a downstream power plant uses the cold river water to condense its steam. But later environmentalists discovered that the mussels in the river won't breed in cold water. Now they are endangered. More about the river temperature below. One method to add more oxygen to the tailwater is to install auto-venting turbines (AVT). The figure below shows the output of a regular turbine vs. an AVT. "The entrainment of air is obvious in the photos. Dissolved oxygen improvement at J. Strom Thurmond ranges from 2-3 mg/l depending on the number of units in operation." [energy]
The figure below shows two more alternatives for adding oxygen. One is to lay hoses along the bottom and pump oxygen bubbles out of them. Other dams have done this. They store the oxygen as liquid oxygen. They would need more than one truck load of liquid oxygen each day. So this alternative is more expensive than the other alternative, which is to force water down to the inlet from the surface using surface water pumps. This pump solution has also been used at other dams. The pumps are variable speed so that the velocity of the water is enough to reach the inlet but not enough to stir up bottom sediments. (The figure is not to scale because there is more distance between the inlet and the bottom than there is between the inlet and the top.) The pump solution is cheaper, but the surface water is warm. This solution would increase the temperature of the tailwaters. That is good news for the mussels, but bad news for the trout and power plant. [energy] I could not determine if there exists a "sweet spot" that would make both the mussels and trout happy.
The long term plan for the dam includes the replacement of the turbines in 2024. This paper says a more detailed study would have to be done, including an environment impact study, before a choice can be made. Because the article converts costs to 2017 dollars, I assume that is when it was written. Have they made a decision since then? If so, what was it? If not, they can study it a little more and then it will be 2024 and they can go with the AVT solution. And they have already done an experiment with a warmer river because the lake was lowered 40' during the repair work during 2007-14. Lowering the surface of the lake allowed warmer water to enter the penstocks. What happened to the mussels and trout during that period? [energy]
StoryMaps [The page describes how the author used GIS to count the number of structures that got drowned by the lake. The result was 1,649, which includes 7 schools, 3 churches and 17 cemeteries. It also provides the figure of $594m for the 300' deep secant cutoff wall built from 2007-14.]
This postcard shows the original town of Burnside, KY, that had to be moved to the top of the river bluff.
To put the 553kcfs spillway capacity in perspective, the capacity of the original spillway for the Oroville Dam was 125kcfs. [DeBruler] This video talks about 15,000,000 gallons per sec being released in Feb 2019 with the lake at 748'. The conversion factor is 1 gal = 0.13368 cubic foot. But that gives me a release rate of 2,005kcfs, which is way too much. So I'm confused.
HeidelbergCement [The USACE claims the project to upgrade the foundation went from 2008-13, whereas all other sources claim 2007-14. I think the discrepancy is the amount of time it took to let 40' of water out of the lake before the USACE started and the time it took for the lake to rise 40' to its normal summer time (i.e. recreation) levels. The USACE cares about when it could work, everyone else cares about when they can play.]
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