Without water from the Salt River Project, the Valley would not be the metropolis it is today.
Without the Salt River and Verde Rivers, the Valley of the Sun would not be habitable. Hundreds of years ago, the Hohokam people built extensive, sophisticated canals using that allowed them to irrigate crops. Today's canals follow many of the same paths that the Hohokam used, although the rivers are tightly managed and controlled by a series of reservoirs and canals.
Here's a tour of the rivers and the engineering marvels that have made Phoenix and the surrounding Valley what they are today.