Raccoon Mountain Pumped-Storage Reservoir

The water goes up. The water goes down.

Raccoon Mountain is located just west of Chattanooga, Tennessee. Atop the mountain is a Tennessee Valley Authority power generation reservoir. Built between 1970 and 1978, the reservoir is a pumped-storage hydroelectric power station. Raccoon Mountain has been on my “local” bucket list for several years now—finally made it!

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View across the Raccoon Mountain reservoir toward the Inlet tower.

It is “pumped-storage” because water is pumped up to the reservoir and held there. When additional electrical power is needed, valves are opened and the water flows down through a power generation plant, capable of producing 1,650 MW of power.

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Schematic of the Raccoon Mountain Pumped-Storage power reservoir and power generating plant. (TVA Graphic)

The water turbine-generators also serve as motor-pumps to fill the reservoir. According to TVA information, it takes 28 hours to fill the reservoir.

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The inlet tower. It is the top of a vertical tunnel more than 1000 feet down into the mountain to supply water pressure to the turbine generators. The tower is more than 200 feet “tall” from the bottom of the reservoir; the “windows” prevent water from swirling when water is pumped into the reservoir.

The water is pumped from Nickajack Lake on the Tennessee River, several miles from what locals refer to as Moccasin Bend on the west side of Chattanooga. The 528-acre storage reservoir is contained by a rock-filled dam that is 230 feet high and more than a mile long—the largest rock-filled dam ever built by the TVA. It holds enough water to run the generators for 22 hours.

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Lake Nickajack on the Tennessee River near the Raccoon Mountain power generating plant.

Water flows in and out of the reservoir through the inlet facility. For power generation, water flows in the inlet and down more than 1000 feet through a concrete-lined tunnel drilled down through the mountain and then horizontally to the power generator station—all tucked deep inside the mountain. The water flow into the generator turbines is controlled by huge spherical valves, similar to spherical valves found in household plumbing.

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A spherical valve that controls the flow of water into the power-generating water turbine. The opening is more than six feet in diameter.

The water exits the water turbine into a discharge area on the Tennessee River. The rush of water from the discharge would create significant turbulence in the river, but TVA installed a series of “deflector shields” to slow and disperse the flow of water so that it enters the river without creating a hazard. The deflector shields also make a natural fishing pier that is popular among local sport fishermen.

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The “deflector shields” that slow the flow of water into the Tennessee River when the power plant is generating.

On top of the mountain, next to the reservoir is a Visitor’s Center (currently closed for renovations), access to hiking trails, and a road that travels across the top of the mile-long dam. About half way around the dam, there is an exit to Laurel Point that goes to a large recreation area with a ball field, picnic tables, more hiking trails, and bathrooms. After leaving the dam road, there is a parking area that provides a spectacular panoramic view of Chattanooga and Lookout Mountain.

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View of Chattanooga from atop Raccoon Mountain.

In addition to hiking trails, the TVA area offers challenging road and mountain biking trails, and is the home of the Raccoon Mountain Marathon, Half Marathon, Double Half and Relay that attract runners from all over North America. Also, there are 5K and 10K races each year.

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Lookout Mountain viewed from Raccoon Mountain. Lookout Mountain is home to Rock City, Ruby Falls, and the Incline Railway in Chattanooga, Tennessee. The Tennessee River is visible at the foot of the mountain.

To begin your Raccoon Mountain adventure, take Interstate 24 to Exit 174, west of Chattanooga and follow signs to Raccoon Mountain and to the TVA pumped-storage facility. In the area, there is a large campground for tents, trailers, and motor homes. Adjacent to the campground is the entrance to Raccoon Mountain caverns.

Raccoon Mountain Reservoir Gallery

Photography ©2016 Jeff Richmond

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