This necessitated a highly coordinated society. Floods would have regularly broken through headgates and filled channels with sediment, which meant the Hohokam constantly repaired, cleaned and diverted the canals. But it's a challenge for hydraulic engineers, especially since epic summer monsoons dump rain that rushes along rock-hard surfaces. Multiple mountain ranges tower around and through metro Phoenix, making it, to my mind, the best big city in the world for hiking. These design features helped keep the flow at a consistent rate while minimising siltation and erosion.Īs the Hohokam expanded their network, they had to contend with the area's complex topography. Then they slimmed as they branched into lateral canals and furrows, like watery arteries and capillaries writ large. At the heart of the system, the Salt River, the channels started out large – more than 25m wide in some places. With these simple tools, they created a precise downhill gradient of 0.3 to 0.5m every 1.6km. It provided ample plants and animals, in addition to the Hohokam's staple crops of maize, squash, beans and cotton.īecause the Hohokam had no draft animals, they carved the canals by hand using hafted stone hoes. The Sonoran Desert is the world's most biodiverse desert. But visit the north-eastern outskirts of the city – where kayakers paddle the Salt past sienna mountains, cottonwoods and wild horses splashing along the shore – and you can sense the possibilities that greeted the Hohokam when they migrated here from southern Arizona. Today, the dammed Salt River is mostly dry in Phoenix. "So, by the time you get to the Hohokam, they were skilled hydraulic engineers."
HOHOKAM NATIVE AMERICAN TRIAL
Through trial and error, these ancient river people accumulated knowledge that was passed down from generation to generation, Huckleberry notes. The oldest waterways archaeologists have found date to 1500 BCE and diverted water from the Santa Cruz River in Tucson. Native Americans have been building canals in Arizona for at least 3,500 years. Soon after, Swilling began scouring out the debris-clogged ditches to bring agriculture back to the region. He realised that, centuries before, some society had farmed this desert. In 1867, the city's founding father, Jack Swilling – a prospector who had fought on both sides of the Civil War – stood above the Salt River Valley and saw the remnants of irrigation channels squiggling across the landscape like stretchmarks. They are a major reason Phoenix exists, and the city's name hints at their mysterious origins.
The canals deliver irrigation and drinking water throughout the metro area, allowing millions of people to live in this sun-baked desert.
And I've chatted with long-time residents who fondly recall fashioning water skis from plywood, tying a tow rope to a pickup truck and jetting through their neighbourhoods in a spray of water and dust. I've joined wildlife watchers strolling the main Arizona Canal on a summer evening to watch Mexican free-tailed bats make a mass fluttering exodus from their roost. As a native Phoenician, I've spent many hours bicycling their banks alongside joggers and fishermen casting for carp. Crisscrossing Phoenix, Arizona, are 180 miles of canals – more than twice as many as Venice and Amsterdam combined.
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