Roosevelt Dam was built when Arizona was still a Territory — an exception to the federal government's stance toward its territories.
But statehood was pretty much in the bag by then and Teddy Roosevelt, who signed the legislation enabling the dam, was solidly behind Western expansion.
I wrote a longer piece about the dam when it celebrated its 100th birthday last year.
Its impact on the growth of the Valley of the Sun can not be overstated. It watered the cotton fields that lured the tire manufacturers during World War I. It provided irrigation for a citrus industry and it enabled the growth of Phoenix and its sister cities.