Dam of its scale had ever been attempted; on completion, it was the largest masonry dam in the world. The Hoover Dam is a massive concrete arch-gravity dam, constructed in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada between 1931 and 1936 during the Great Depression. In 1928, Congress authorized the project to build a dam that would control floods, provide irrigation water and produce hydroelectric power. The winning bid to build the dam was submitted by a consortium called Six Companies, Inc. Such a large concrete structure had never been
Course of the Colorado River Bridge carries U.S. Route 89 over the Colorado River. Below here the Colorado flows through the last of Glen Canyon, passing the scenic Horseshoe Bend, before emerging briefly from its canyons at Lee's Ferry, where it is joined by the warm, shallow, muddy Paria River. Historically a ford used by Native Americans, explorers and settlers, Lee's Ferry serves as the dividing point between the Upper and Lower Colorado River Basins, which were each allocated one-half of the Colorado River flow in the Colorado River Compact of 1922. Below Lee's Ferry the Colorado begins to trend more south than southwest, through