Grand Coulee Dam is a concrete gravity dam on the Columbia River in the U.S. state of Washington, built to produce hydroelectric power and provide irrigation water. Constructed between 1933 and 1942, Grand Coulee originally had only two powerhouses. The third powerhouse, completed in 1974 to increase energy production, makes Grand Coulee the largest power station in the United States by nameplate-capacity at 6,809 MW. However, in terms of yearly power production, Grand Coulee places fifth after a number of nuclear facilities to the south, like Palo Verde west of Phoenix. This is because river flow varies throughout the year. For example, while the dam may generate at nameplate-capacity in the spring, decreased river flow in the fall means less power can be generated the rest of the year, resulting in a lower capacity factor.Plan to visit Grand Coulee Dam during your Coulee Dam vacation using our convenient Coulee Dam road trip planning app .
The proposal to build the dam was the focus of a bitter debate during the 1920s between two groups. One group wanted to irrigate the ancient Grand Coulee with a gravity canal while the other pursued a high dam and pumping scheme. The dam supporters won in 1933, but for fiscal reasons the initial design was for a "low dam" 290ft tall which would generate electricity without supporting irrigation. That year, the U.S. Bureau of Reclamation and a consortium of three companies called MWAK (Mason-Walsh-Atkinson Kier Company) began construction. After visiting the construction site in August 1934, President Franklin Delano Roosevelt began endorsing the "high dam" design which, at high, would provide enough electricity to pump water into the Columbia basin for irrigation. The high dam was approved by Congress in 1935 and completed in 1942. The first waters over-topped Grand Coulee's spillway on of that year.
Grand Coulee Dam Reviews
My hotel was across from the dam, and I got to see it every day. and walk to it on weekends. It's not what you see, but what it took to build what you see, that is the marvel. During the summer there ... more »
We toured the outside area and inside visitor center. Did not take the dam tour as did not have the time. The visitor center did a good job of telling about the dam. Very interesting. Majestic. more »
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