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
Glen Canyon Dam about 5 million people in Arizona, Colorado, Nevada, New Mexico, Utah and Wyoming, and is sold to utilities in these states as 20-year contracts. Power sales have been managed by the Western Area Power Administration since 1977. Glen Canyon Dam generates enough power to offset 6.7 billion pounds (3 billion kg) of carbon dioxide emissions each year. However, drought conditions in the 21st century have reduced the amount of hydropower available from Glen Canyon Dam. An unusual feature of the Glen Canyon power plant is the Kentucky bluegrass lawn occupying the crescent between the dam and hydroelectric plant. At the