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
Steamboats of the Colorado River to make only two trips with forty tons in that time. Trips farther up river to the vicinity of Fort Mohave took at least twice as long. The same difficulty plagued the "Colorado" carrying cargo between the estuary and Arizona City. By the fall of 1863 there was a backlog of twelve hundred tons of freight at Arizona City or in ships anchored in the estuary waiting to be brought up river. Between ten and fifty tons of ore waiting to be brought down to the estuary at each of the landings up river above Arizona City. Some of this