Water is the defining issue of Arizona's future. The state receives 2.8 million acre-feet annually from the Colorado River — water that supports 80% of the population through the Central Arizona Project canal. With Lake Mead and Lake Powell at historic lows, the first-ever shortage declarations forcing cuts to Arizona's allocation, and tribal water rights adding complexity, the state faces an existential infrastructure challenge.
In 1922, seven states divided the Colorado River's water via the Colorado River Compact. Arizona initially refused to sign, holding out until 1944. The compact divided the basin into Upper (Wyoming, Colorado, Utah, New Mexico) and Lower (Arizona, Nevada, California) divisions, each allocated 7.5 million acre-feet annually.
The problem: the compact was based on abnormally wet years. The river's actual average flow is significantly less than the 15 million acre-feet allocated.
Authorized in 1968 and operational by 1985, the CAP is a 336-mile canal system that diverts Colorado River water from Lake Havasu to Phoenix and Tucson. It is the largest and most expensive aqueduct system ever constructed in the United States.
The Bureau of Reclamation declared the first-ever Tier 1 shortage on the Colorado River, forcing Arizona to reduce its usage by 512,000 acre-feet — roughly 18% of its allocation. The cuts primarily hit agriculture in Pinal County.
Arizona's 22 tribal nations hold significant water rights — rights that in many cases predate state water law. The Gila River Indian Community, Salt River Pima-Maricopa, and Tohono O'odham Nation are among the largest rights holders. As the crisis deepens, tribal water becomes increasingly strategic.
Arizona exists because of engineered water. Without the CAP, Colorado River allocations, and groundwater, Phoenix and Tucson could not sustain their populations. The water crisis is not a future concern — it is happening now, with real cuts affecting real people. Every other topic in this wiki — defense, border, infrastructure, governance — is downstream of water.