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 interest in irrigation projects. The Bureau of Reclamation, desirous of a major project that would bolster its reputation, was focusing on the Boulder Canyon Project that resulted in the Hoover Dam. Reclamation was authorized to conduct a study in 1923, but the project's cost made federal officials reluctant. The Washington state proposals received little support from those further east, who feared the irrigation would result in more crops, depressing prices. With President Coolidge opposed to the project, bills to appropriate money for surveys of the Grand Coulee site failed. In 1925, Congress authorized a U.S. Army Corps of Engineers study