Wednesday, September 29, 2010

Glen Canyon Dam

The Glen Canyon Dam is the second largest dam on the Colorado River and is located at Page, Arizona. Its main purposes include generating electrical power, storing water for the arid southwestern, and providing water recreation opportunities. The dam generates an average of 451 megawatts representing 6% of the total electricity generated in Arizona and 13% of the electricity generated in Utah. Damming the Colorado River created the large reservoir called Lake Powell, the second largest man-made reservoir in the United States after Lake Mead at the other end of the Grand Canyon.




The tour of the dam costs $5 and lasts about 45 minutes. Below is a "runner" recently removed from service when replaced by a newer, more efficient model. The runners are what rotate as the water surges through them, causing the turbines to rotate and generate electricity. There are 8 turbines, each with a runner. Notice the Glen Canyon bridge high above in the background.




Here's another view of the bridge overhead, taken from the generator level. It was interesting to learn that the bridge was built first. Otherwise, workers and equipment would have had to drive over 200 miles to get to the other side. The bridge was fully constructed in California, then disassembled, and half driven to each side of the canyon for re-assembly.



Concrete placement for the dam ran 24 hours a day for three years -- over 5 million cubic yards were mixed in a 21 story facility on site. That's enough concrete to pave a four lane highway from Phoenix to Chicago! Then it took 3 years to install the turbines and generators and 17 years to fill Lake Powell to full-pool level.

Here's the turbine room with its 8 generators, four of which were running when we toured. Each generator's shaft weights 40 tons and the water pressure turns each shaft at 150 rpm, generating 200,000 horsepower. That represents 15,000,000 gallons of water per minute when all 8 generators are operating! 1.5 million users receive their energy from this dam, which has an estimated life of 300 to 500 years.



The dam was built by the Bureau of Reclamation and has already more than paid for itself with its 1.5 billion in revenues. All the expenses of the Bureau of Reclamation are paid by the electricity revenues generated each year, so no taxpayer funds are required.

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