09/16/2004 - Duke Dams

9/16/2004 - Extra: Duke’s East Fork dams

Background for Students and Parents

The dams: Four of Duke Power’s six Jackson County hydroelectric dams stair-step down the East Fork of the Tuckaseigee River, beginning at the top with Wolf Creek and Tanassee Creek, then continuing downriver to Bear Creek and Cedar Cliff.

Cedar Cliff discharges into the West Fork, just above the confluence of the East and West forks, to make the main stem of the Tuckaseigee River.

The Tuckaseigee flows west from Jackson County, through Swain and into the Tennessee Valley Authority’s Fontana Reservoir.

How dams work: These dams are huge. They are made of a clay core with an earth and rock fill.

To keep excess storm waters from wearing away at a dam by flowing over its top, the dam’s spillway gates open. If an even greater opening is needed to protect the dam, there are specially-constructed dam sections called “fuse plugs” that have been designed to wash away.

During last week’s flooding triggered by Hurricane Frances, some 13,000 cubic feet per second spilled from the East Fork reservoirs, as compared to a normal flow of 700 cfs.

Important terms to know: “Cubic foot”: One cubic foot is a cube measuring one foot, or 12 inches, on each side. If you filled that cube with water, you’d have 7.48 gallons of water weighing a total of 62.4 pounds.

“Cubic feet per second,” or “cfs”: A measurement of water flow that’s equal to one cubic foot of water passing a given point for an entire second. If you measured1,000 cfs at a dam, it would mean that 448.8 gallons flowed past that dam in one second. If water kept flowing at that same 1,000 cfs rate, 26,928 gallons would go by in a minute. After an hour, you would have seen 1,615,680 gallons pass by!

Source: Duke Power