Phoenix is in trouble. In 2024, the Arizona capital recorded 113 consecutive days of 100 degrees Fahrenheit or greater; the summers that were always hot but were still bearable are becoming more and more unbearable. As I write this in March of 2026, temperatures are already topping 100 degrees. While climate change explains some of the hotter temperatures, a bigger culprit is the endless concrete sprawl that traps heat in the daytime and doesn’t let it go at night. Phoenicians are long used to getting up at 5 in the morning to walk their dogs on concrete that doesn’t burn their paws; that time is getting earlier and earlier.
Then there’s the water. Phoenix sits on top of an aquifer and, like everywhere else in the west, they began draining that aquifer faster than they could refill it. So they supplemented. Phoenix sits at the confluence where the Agua Fria, Verde, and Salt Rivers all join with the Gila River; the Gila then runs west through the Sonoran Desert until it reaches the Colorado River some 200 miles downstream. Or, rather, it used to run west through the Sonoran. These rivers are completely used up by Phoenix, its suburbs, the Indian reservations in the metro area, and the farms in the exurbs. Waddell Dam, Horseshoe Dam, Bartlett Dam, Theodore Roosevelt Dam, Horse Mesa Dam, Mormon Flat Dam, Stewart Mountain Dam, and Granite Reef Dam create the lakes where Phoenicians go to escape the heat and ensure that one hundred percent of the rivers are available to Phoenix (less the millions of gallons that evaporate daily in the Arizona heat). West of Phoenix, the Gila runs dry until it reaches the Colorado.
This water is, or rather was, guaranteed to Phoenix by the Colorado River Compact. The compact was signed in 1922 and assumed that the 1920-1921 flows of the river were representative of the river as a whole, but this turned out to be wrong in the worst possible way: those years had far more snowpack and therefore far more river water than average, decades before the effects of climate change began to be felt. The struggle to allocate the actual flow of the Colorado, not the paper flow, is a story of election fraud and bribery and lawsuits and gunfights and dynamite attacks involving states and militias and tribes and cities and feds and Mexicans, but that’s not the book I’m reviewing here. And to paraphrase Lord Palmerston, only three people have really understood the so-called Law of the River: the commissioner of the Bureau of Reclamation, who is dead; a Navajo lawyer, who has gone mad; and I, who have forgotten all about it. So we won’t dwell on the Colorado. The upshot is that thanks to a lot of conservation efforts, Arizona has so far managed with the allocation it was given.
But Phoenix is getting more and more people and less and less snowpack. Arizona farmers are giving up more land and cities are instituting more stringent water restrictions, even as the population continues to increase and the thirsty data centers move in. In 2000, the seven western states in the Colorado River basin agreed to a set of guidelines to allocate the much-diminished river; those guidelines expire at the end of this year. The federal government gave a deadline of February 2026 for the seven states to come to a new agreement, and those states blew past that deadline without anything close to an agreement. The federal government is now in charge of determining how the river will be allocated.
This is a really bad time for the states to be arguing about river allocation; the winter of 2025-26 had the worst snowpack since the compact was signed and probably since much earlier, though records get shakier the farther back you go. This year we’ll avoid disaster by releasing years’ worth of water stored in a Wyoming reservoir. That won’t be an option next year. As the youngest state, Arizona has the weakest water rights; those rights would be the first to go in a crisis. Some of the options that the government has on the table involve cutting off the Central Arizona Project entirely, leaving Phoenix to drain the aquifer dry and collapse the whole metro area into a sinkhole.
This coming crisis has not passed unnoticed. Many people and publications have tried to explain these issues to a national audience, and a lot of them have hit on the same hook.
For example, the July 2024 cover story of The Atlantic tells the story of Phoenix. It opens with this:
No one knows why the Hohokam Indians vanished. They had carved hundreds of miles of canals in the Sonoran Desert with stone tools and channeled the waters of the Salt and Gila Rivers to irrigate their crops for a thousand years until, in the middle of the 15th century, because of social conflict or climate change—drought, floods—their technology became obsolete, their civilization collapsed, and the Hohokam scattered. Four hundred years later, when white settlers reached the territory of southern Arizona, they found the ruins of abandoned canals, cleared them out with shovels, and built crude weirs of trees and rocks across the Salt River to push water back into the desert. Aware of a lost civilization in the Valley, they named the new settlement Phoenix.The Sierra Club’s cover story in 2022 described the coming Colorado River crisis. Their introduction ends with this:
No one knows exactly why, in the 14th century, the Hohokam abandoned Pueblo Grande and other settlements across the Salt River Valley. Two hypotheses (perhaps not mutually exclusive) are that the Hohokam were laid low by prolonged drought and that hundreds of years of relentless irrigation salinized the soil, which in turn led to a collapse in agriculture…The secret of the culture’s disappearance from the region may be encapsulated in its name. Hohokam derives from a word in the language of the Akimel O’odham, a contemporary Native nation. It means “all used up” or “exhausted.”There are many more invocations of the Hohokam; I’ll quote just one more here to drive home the point. The ur-text of writing on the water crisis in the west, the book that all others cite as their inspiration, is the 1985 book Cadillac Desert. The chapter that discusses the Central Arizona Project begins this way:
The original 400,000 Arizonans were, for the most part, members of the Hohokam culture, a civilization that thrived uninterrupted near the confluence of the Gila, Salt, and Verde rivers for at least a thousand years, until about 1400, when it disappeared. The Hohokam, by A.D. 800, had already established a civilization that rivaled the Aztec, Inca, and Maya further south. They lived in small cities; the ruins of one of them, Pueblo Grande, occupied a large piece of land just about where downtown Phoenix is today. Superb flint and stone masons and excellent potters, they also worked beautifully with shells; they may have traded with people living on the Mexican coasts. For sport, they built enclosed ball courts very much like those of the Maya, who probably gave them the idea. When it came to irrigation, however, the Hohokam were in a league by themselves.It’s easy to see why the Hohokam story is used as a hook. It’s too good not to use. A people settle by the confluence of the Salt and Gila rivers and build a great civilization until the changing climate or their overuse of water forces them to leave. The writers of all these pieces start by saying the disappearance of the Hohokam is a mystery, but then make it clear that the answer to this mystery is the same as whatever they believe to be the biggest problem with modern-day Phoenix: climate change, irrigation overuse, poisoned crops, social conflict, etc.
They were more populous than any culture around. Why then should they disappear? Drought remains a possibility — perhaps a twenty-year drought the likes of which they had never seen — but an equally plausible explanation is that they irrigated too much and waterlogged the land, leading to intractable problems with salt buildup in the soil, which would have poisoned the crops. In either case, the mysterious disappearance of Hohokam civilization seems linked to water: they either had too little or used too much. And that is the exactly the problem that Arizona faces today.
But is it true that nobody knows why the Hohokam vanished? Archaeological investigations into Hohokam society have revealed several great houses, dozens of classic Meso-American ball courts, and a massive network of dams and irrigation canals. But archaeology tells us nothing about why the Hohokam left. Where else could we go to investigate this mystery? Where could we turn to see if Phoenix is heading down a well-trodden path towards destruction? How could we find out what happened to the Hohokam?
What if we asked them?
by Anonymous, Astral Codex Ten | Read more:
[ed. Less about current water problems (and possible solutions) in the Phoenix area that exists today and more about the history of Hohokam society that predated it in the same location. A very interesting and detailed account of a unique and forward-thinking society extremely advanced for its time. See also: Friday Book Club - Cadillac Desert (DS).]
