The 180 miles of canals that traverse Phoenix, Arizona, allow millions of people to live in the sun-scorched desert. Yet, most people are unaware of the mysterious origins of these canals.
In the Phoenix area of Arizona, 180 miles of canals spread across the region like a web. This area is more than twice as long as the combined length of canals in Venice and Amsterdam.
As a local Phoenician, I have spent hours cycling along these canals. On these canal banks, countless people are seen jogging, and fishermen navigate their boats within the canals.
On a summer evening, I joined wildlife watchers along the Central Arizona Canal to witness Mexican Free-Tailed bats emerging in flocks from their roost.
In long chats with locals, I learned how people used to ski along these canals by holding ropes tied to their vehicles, using plywood planks, and traveling from one neighborhood to another while creating splashes of water and dust.
The canals supply irrigation and drinking water throughout the metro area, enabling millions to live in this sun-scorched desert. They are a significant reason for Phoenix’s existence, and the city’s name hints at their mysterious origins.
In 1867, city founder Jack Swilling, who fought on both sides of the Civil War, stood above the Salt River and observed the remnants of irrigation channels.
He realized that centuries ago, a society had farmed this desert. Shortly after, efforts began to clear and restore the irrigation channels.
I predict that a new city will emerge from the old ruins and ashes, much like Phoenix did.
Three years later, Swilling and other Anglo founders met to consider names for their settlement. The majority favored names like “Caduaville” and “Stonewall.” Fortunately, the eccentric English adventurer “Lord” Darrell Dupa suggested a name inspired by the restoration of the canals.
He thought that great people had lived here in the past and that another great generation would live here in the future. I predict that a new city will rise from the old ruins and ashes like Phoenix.
This great society was called the Hohokam. Between 100 and 1450 AD, they built 1000 miles of canals, making it the largest canal system in America north of Peru. This advanced irrigation system conserved river water and seven inches of annual rainfall, creating a system to irrigate more than 100,000 acres of farmland. They constructed this system using stones and sticks by hand.
Kathy Henderson, principal investigator at Desert Archaeology, a cultural resource management and research company in Arizona, said the engineering was exceptional. “We don’t see any signs where they were small. They certainly knew the art of delivering water over long distances.”
The engineering is exceptional… they must have been very adept at transporting water over long distances.
For Gary Huckleberry, a geologist and associate researcher at the University of Arizona, the Hohokam and their ancestors remain relevant today in terms of water.
He said, “We have some serious water issues in the Southwest. The Colorado River is a crucial water source for the Southwest, and a significant portion of its water is allocated. With growing population and climate change, how will we cope? I think we need to learn from past societies that managed water thousands of years ago.”
Native Americans have been building canals in Arizona for at least 3500 years. The oldest waterways have been dated to 1500 BC, and water was diverted from the Santa Cruz River in Tucson. Huckleberry says that through trial and error, these ancient riverine people accumulated knowledge passed down through generations. So, by the time you reach the Hohokam, they were skilled hydraulic engineers.
Today, the Salt River in Phoenix is mostly dry. But visiting the northeastern suburbs of the city reveals how the ancient engineers managed the canals with precise ‘downhill gradients’ or slopes every 1.6 kilometers, ranging from 0.3 to 0.5 meters. In the center of the system, canals originating from the Salt River were kept wide, some places more than 25 meters. Sub-canals and laterals were narrower, resembling large water arteries and veins. These design features minimized silt and erosion while maintaining a consistent flow.
As the Hohokam expanded their network, they encountered the region’s uneven and rocky terrain. Looking at the surrounding mountain ranges of Metro Phoenix, I thought this would be a perfect city for hiking.
But creating these waterways was a challenge for the experts, especially during summer monsoon rains when torrents of water rush down from the rocks. Floods would likely break levees and fill canals with silt and mud, meaning the Hohokam had to continuously repair, clean, and redirect the canals. This required a highly coordinated society.
Henderson said it required cooperation because all users of the canal water had to agree not only on the canal’s construction but also on its water distribution. Users had to agree on certain conditions to run the entire system.
For example, she explained, all farmers could not open their field gates simultaneously because this would deprive the lands at the end of the canal of water. Thus, the Hohokam committed to sharing water and adhering to a schedule. This also meant that water rights had to be interpreted.
By the 13th century, about 50,000 Hohokam people lived in villages specific distances from the canal system. This indicates that water and canal lands were largely equitably distributed.
Over the centuries, the canal system was restored several times, but its basic structure remained unchanged. However, after 1300, the society and canals began to decline, and by 1450, the population had vanished. No one knows why. Climate change may have played a role, but there is no evidence of particularly severe climatic changes at that time.
And although some irrigation-dependent civilizations may have faced salinity and thorns on their lands, historical evidence suggests that the Hohokam must have adopted some methods to prevent salinity.
Although archaeologists once thought the Hohokam population was destroyed by a natural disaster, modern techniques reveal that it was likely a gradual decline due to a complex mix of factors like community disunity, floods, flood debris, decline in wild food resources, and internal conflicts.
Huckleberry says there is much to learn from the Hohokam and their ancestors, who used canal irrigation for 3000 years.
He said, “For me, it is a definition of sustainability. They taught us how to practice sustainable farming, manage water, avoid degrading the soil, and provide insights on how we can deal with our current situation. I think a key lesson is not to put all your eggs in one basket; you prepare for the worst and diversify your strategies.”
The Hohokam may have stopped managing their canal system, but they did not disappear. Their story continues with their descendants, the Akimel O’odham (“River People”) and Tohono O’odham (“Desert People”), who still live in central and southern Arizona.
Their legacy also lives on in the city’s modern canals, many of which were rebuilt by rediscovering Hohokam expertise. The Grand Canal is now being developed as part of a coordinated project connecting Phoenix’s eastern and western suburbs. Phoenix Mayor Kate Gallego announced in 2020 that we are integrating canals into our communities to improve neighborhood access.
The Hohokam’s legacy is also preserved in their village, Pueblo Grande, which is a museum and archaeological park where visitors can see ball courts, (formal houses), and reconstructed adobe homes. Hikers can explore South Mountain.
But perhaps one of the most significant legacies of the Hohokam is less tangible: the idea that through cooperation, determination, and shared knowledge, it is possible to sustain life in this sun-scorched desert.
