Grand Coulee Dam crane-lifted buckets, each supporting eight tons of concrete. To cool the concrete and facilitate curing, about of piping was placed throughout the hardening mass. Cold water from the river was pumped into the pipes, reducing the temperature within the forms from to . This caused the dam to contract about eight inches in length; the resulting gaps were filled with grout. Until the project began, the stretch of the Columbia River where the dam was to rise was as yet unbridged, making it difficult to move men and materials. In , the Grand Coulee Bridge (a permanent highway bridge) was
Grand Coulee Dam of electricity. Each generator is supplied with water by an individual penstock. The largest of these feed the Third Powerplant and are in diameter and can supply up to . The dam's power facilities originally had an installed capacity of 1,974 MW but expansions and upgrades have increased generation to 6,809 MW installed, 7,079 MW maximum. Grand Coulee Dam generates 21 TWh of electricity annually. This means the dam generates about 2,397 MW of power on average, which results in a total plant factor efficiency of 35%. In 2014, 20.24 TWh of electricity was generated. Grand Coulee Dam's spillway is