The Central Arizona Project canal near Picacho Peak.

Jeffry Scott / Arizona Daily Star 2001

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The Central Arizona Project is a pretty impressive accomplishment — a 336-mile uphill river that brings Colorado River water to Tucson from Lake Havasu.

Earlier canals were even more impressive, when you consider the circumstances under which they were built.

Our earliest settlers built elaborate irrigation systems to channel the irregular but reliable flows of the Santa Cruz, Rillito and Cañada del Oro to farm fields on the flood plains.


We used to think the Hohokam were the first to settle in our river valleys, but archaeological digs of the past two decades have expanded knowledge of more ancient civilizations.

Canals excavated at the foot of Sentinel Peak (“A” Mountain) are the earliest known in the Southwest and trace to an Early Agricultural period going back to 2100 B.C.

Farm fields lined portions of the Santa Cruz River when the Spaniards arrived, and successive waves of pioneers and settlers — Mexican, Chinese and Anglo — grew food along the Tucson stretch of the Santa Cruz.

The seasonal flows and reliable springs of the region dried up long ago as a growing city mined its aquifer and lowered the water table — creating the need for the CAP canal.

Contact reporter Tom Beal at or 573-4158.