Visit to The Grand Coulee Dam 2002
The aerial view below shows Lake Roosevelt, the reservoir formed behind the Grand Coulee dam (capacity = 9,562,000 acre-feet of water as the Americans quaintly put it) and in the top right corner Banks Lake for which water is obtained from lake Roosevelt via the pump/generator plant at Grand Coulee dam. This facility, located on the west upstream side of the dam, lifts water from the reservoir up 280 feet into the Banks Lake feeder canal above the river gorge.
Construction of the pumping plant began with the original dam construction in the thirties but was delayed by the onset of World War II when power generation was given highest priority. After the war construction was resumed and the plant was finally made operational in 1951. In 1973 the plant was extended. The pump bay was doubled in length to the south and six 67,500 horsepower pump/generators were added (the last in 1983) to the original six 65,000 horsepower pumps providing 12 in all.
Each pump lifts water from Lake Roosevelt up through a 12 foot diameter discharge pipe to the feeder canal above. For most of their length the discharge pipes are buried in the rocky cliff to the west but at the top of the hill they emerge and can be seen as 12 silver pipes leading to the head works of the feeder canal.
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 The adjacent picture shows the activity of installing one of the units. On the whole of the site it is difficult to visually grasp the scale of all the works. This picture does help to to give an udea of the size invoved | Finally we reach the Turbine Hall - a vast empty space with the six 33ft blue circular covers for the turbine chambers
One can distinguish different frequencies in the steady hum that pervades the space
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 | All this highly impressive Civil and Electrical Engineering Construction was quite overwhelming - everything well thought out and planned to the nth degree. Too much perfection always worries me too - little humanity - but talking to our guide soon put it right - all the materials for making the cement for the dam (12 million cu.yds) had to be imported to the site but a wrong estimate of the quantity required was made and the adjacent photo shows the "mountain" of aggregate that was left over when the dam was completed.
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| We stayed overnight by the dam - witnessed the laser show and stayed in a house that had been used by the design engineers and surveyors run by a now retired mayor of the community. After the tour we explored some of the Colorado River towards the Canadian border and found other dams and some fantastic scenery. |
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The lack of any visible structures for terminating O/H cables or for switchgear creates a unexpectedly clean and efficient impression of the site. This must have been a prime consideration in the design and the use of the walls of the power houses and of the dam it self for termination enables this to be achieved.