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 the river, except for the "Searchlight" that lingered on as property of the U. S. Reclamation Service until it was sunk in 1916. Steamboats were tried in Glen Canyon, the Green River in Utah and Wyoming and the Grand River, (after 1921 renamed as the upper part of the Colorado River), above its confluence with the Green River in Utah and in Colorado. Unlike the Lower Colorado, the railroads made possible most of this steam navigation on the Upper Colorado, bringing in the boats or their parts and their fuel to the points on the river where they were assembled