Parker Dam Powerplant Virtual Tour
Parker Dam Powerplant Virtual Tour
Parker Dam, several miles north of Parker, AZ, inundates a portion of the Colorado River to form Lake Havasu. It was built in the
thirties, mainly to form a headwater for the Colorado River Aqueduct, which provides a source of water for Southern California. A second
aqeduct system was built in the eighties to bring water from Lake Havasu to the Phoenix area.
Parker is regarded as the "deepest" dam in the world. (Huh?) Since it is so
far down to bedrock in this area, 73% of the dam's structure is below the
water! However, what is above the water is still mighty impressive.
Until mid-1997, Parker Dam's powerplant (the big grey building to the left of the dam in the vidcap above) was open to the public. It
was a laid-back, self-guided tour, free of charge, and usually uncrowded.
It was a great way to get an up-close and personal look at a medium-size
hydroelectric station without braving the noisy crowds of THAT
BIG DAM near Las Vegas.
Alas, thanks to "people" like the OKC Bomber, the government decided to
close Parker and Davis powerplants to the public. I wasn't too sorry to
see Davis closed (its tour was lacking, showing just parts of the
operation, and much of what was shown was behind glass windows), but the presentation at Parker was OUTSTANDING. Everything was laid out before your eyes and carefully explained. You could even touch and walk down into the heart of two of the massive generators and see the foot-and-a-half diameter shaft whirling. What an incredible sight! No powerplant tour I have been on to date has offered anywhere near the experience that Parker's did.
OK, enough rambling! On with the virtual tour.
Here is what you saw when you started the tour. The balcony offered an impressive view of the dam, and pushing a button
produced a recorded message telling a little about the dam and the Bureau
of Reclamation.
After boarding the small elevator, you descended about 4 stories to
the generator deck. After signing in the guest book and picking up a brochure,
you saw this:
The four generators, larger than life. Each has a small light on top
which is lit if it is in operation. Half of the electricity they produce
is used in the process of pumping water along the Colorado River Aqueduct
to Lake Mathews, Diamond Valley Reservoir and water districts in the San Diego area. The spec plate on each unit states that the shaft rotates at 94.7 rpm. (I always remember that figure because the first time I saw the plant back in August '83 one of my favorite stations was 94.7 KMET in L.A. (Whoo-Ya!) ) Also stated is that the power output is 6900 volts at 2510 amps (making 17,319,000 watts per turbine. - enough to light 173,000 light bulbs, or pump a LOT of water!) I think these plates are out of date though, as the Bureau
of Reclamation's page on Parker Dam quotes them as producing 30,000,000
watts each, almost twice the original capacity. (Or could my math be off...?)
Here is the spare turbine and thrust bearing kept on hand, and the beam
used to lift the entire rotor assembly (200 TONS!!) The spare parts are situated between the two middle generators, and stairways leading to the insides of the generators are visible. There was even a small visitors' lounge. Here are some
of the pictures which were on display, chronicling the powerplant's construction:
Notice the size of the men in the lower left picture.This is a good
view of the lifting beam in action. The large cylinder just below the beam
is the generator's rotor, which is rotated 94.7 times a minute by the water turbine below the
floor. The rotating drum contains a massive electromagnet, charged by a device called an "exciter", and the strong magnetic field moves past the stator
windings, mounted in the stationary housing the men are standing on. The continuously changing magnetic fields induce electric currents in these windings, and three-phase, 60-cycle electricity is born.
(Geek note: The rotational speed tells us that the generator stator has 38 poles: 3600, the number of cycles per minute, divided by 94.7, the number of revolutions per minute, gives us approximately 38. By back-figuring, we can tell that the precise rotational speed is 94.7368421 rpm! (Ain't math fun?) For comparison, steam or gas turbine generators usually have two or four poles, due to the higher shaft speeds of 1800 or 3600 rpm.)
Big hummer! Then you would take the elevator back up and the tour was over. If you
were a "newbie" you left a little smarter about the workings of a hydroelectric
operation. If you were a return visitor, well, it was always impressive,
and the hum of the generators was a nice way to calm the mind after a beer-hazed
weekend on boats and Jet-Skis.
This is the intake structure across the street from the powerhouse.
Massive doors here regulate (in part) the flow of water into the turbines, and allow shutoff of a penstock for major repairs. Electronically-controlled vanes called "wicket gates", surrounding the turbines, provide more precise flow control to respond to electrical demands and regulate grid voltage, VARs and frequency (and of course the river level downstream.) You could see the hydraulic rams that drive the gates when you ventured inside one of the middle generators.
Here is a close-up of the massive chain used to lift one of the five giant
floodgates on the dam face. Since Parker has no spillway, these are opened during periods of high Colorado snowmelt when there is more flow in
the river than can pass through the turbines.
The dam spec plate, up close and in context. Note the Art Deco superstructure
which houses the hoisting equipment for the gates. The designers of the dam had an eye for elegance! For more technical info, visit the Bureau
of Reclamation's Parker Dam page.
Rest in peace, Parker Dam Tour.
( I deeply apologize for the photo quality. These are vidcaps from a standard-8mm video camera, the only thing I had in 1996! (grin) Believe me, I'd be the first in line to go back and take decent quality digital photos if they ever opened the plant again!)
The control room (the
only thing on the tour behind glass!)
View from the other end of the powerhouse
After gazing in awe at the generators and being soothed by their steady
60-cps hum, you would walk outside to the transformer deck. Here is where
the voltage is "stepped up" from 6,900 to 230,000 volts for its journey
across the desert on big steel towers. Another push-button audio presentation
would talk about the transformers and give more information about the dam. This deck, incidentally, provided the most incredible view of the dam.
The water rushing out 
