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How did the 1963 Supreme Court decision affect the Central Arizona Project?

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Colorado River Colorado River, near San Luis, Mex.

The 1963 U.S. Supreme Court decision was a pivotal development for the Central Arizona Project. Following a long and contentious legal battle with California, the Court ruled that Arizona was entitled to an annual allocation of approximately 2.8 million acre-feet of water from the Colorado River, in addition to the entire flow of the Gila River.1

This favorable ruling provided the necessary legal foundation for the state to pursue the massive infrastructure required to transport this water. Consequently, in 1968, the U.S. Congress authorized the construction of the Central Arizona Project, a complex system of pumps and canals designed to deliver Colorado River water to the Phoenix and Tucson metropolitan areas, which was ultimately completed in 1993.1