The Archaeology of Thirst: Is Lake Powell Doomed?
By Bob Hembree
The Hohokam haunt the geological subconscious of our water dreams, as we sleepwalk toward the same sedimentary ending.
Masters of the Desert
The Hohokam knew something we have forgotten—that water is not a commodity but a covenant. For fifteen centuries, these "masters of the desert" inscribed their dreams across the Sonoran landscape in a language of canals and check dams, weirs and headgates. Their irrigation networks spread like neural pathways across 45,000 square miles, channeling the Salt and Gila Rivers through hundreds of miles of hand-dug canals that transformed desert valleys into agricultural oases. Some individual canals stretched over twenty miles, engineering marvels that diverted river water to support vast communities in what would become the Phoenix metropolitan area. They were hydraulic poets, writing verses in flowing water across the Phoenix Basin's ancient terraces.
Walk the Salt River today and you can still trace their ghost channels—phantom tributaries that once carried snowmelt from distant mountains to fields of corn, beans, and squash. The Hohokam engineered sophisticated networks on both sides of the Salt River, while also constructing significant canal systems along the Gila, creating a hydraulic civilization that sustained hundreds of thousands of people across the desert basins of central and southern Arizona. The Hohokam dug by hand what we now accomplish with diesel and dynamite, moving two million cubic yards of earth to create a circulatory system that would have made Leonardo da Vinci weep with envy. They understood what we are only now remembering: that in the desert, water is time itself.
But understanding and enduring are different species of wisdom.
All Used Up
The Pima people, inheritors of this waterlogged landscape, gave the vanished civilization its name: Hohokam—"all used up," "exhausted." The word carries the weight of prophecy, heavy as monsoon clouds that promise rain but deliver only lightning. By 1450 CE, ninety years before Spanish horses first stirred the desert dust, the Hohokam had simply... evaporated. Their cities emptied like cisterns in summer, their people scattered like seeds on the wind.
What happened? The archaeology of absence tells its own story. Tree rings speak of megadroughts that lasted decades—years when the sky forgot how to weep, when rivers became rumors, when even the deepest wells surrendered to the relentless thirst of the desert sun. Population had swelled during the good centuries, villages multiplying like reflections in still water. More mouths meant more fields, more fields meant more canals, more canals meant greater vulnerability to the inevitable arithmetic of scarcity.
Water shortages bred more than crop failures. They spawned political upheaval, the kind of civilizational fever that breaks governments like pottery shards. Archaeological evidence suggests increasing warfare in the Hohokam's final century—not the raiding of nomads, but the desperate conflicts of neighbors competing for liquid life. When the wells ran dry, so did social contracts. The sophisticated hydraulic democracy that had sustained them for millennia cracked like adobe in drought.
The Hohokam didn't simply disappear; they dispersed, flowing like their beloved water toward more promising watersheds. Some migrated south into Mexico, others northeast toward the Rio Grande, still others west to the Colorado River. They carried their hydraulic knowledge like precious seeds, planting new agricultural traditions wherever the soil would accept them. Their ending was not extinction but diaspora—a lesson written in dispersed bloodlines rather than ruined cities.
History's Rhyme Scheme
Mark Twain understood the desert's tendency toward repetition when he observed that "History doesn't repeat itself, but it often rhymes." Today, six centuries later, we are composing the same verse in concrete and steel, CAP canals and check dams, municipal water treatment plants and center-pivot irrigation systems. The rhyme scheme has grown more complex, but the meter remains unchanged: growth, abundance, expansion, scarcity, crisis.
Page, Arizona—that unlikely metropolis carved from sandstone and federal ambition—embodies this recurring poem. Built to service the growth of distant cities, this small town by the Colorado River became a hub for the twin commodities of the modern West: power and water. Page once thrived on the Navajo Generating Station's coal-fired prosperity, its smokestacks writing industrial haikus against the desert sky. Now those stacks stand silent, their poetry exhausted, their usefulness "all used up"—hohokam in the language of federal energy policy.
The town's survival now depends on Lake Powell's blue mirage, on the tourist dollars that flow toward Glen Canyon's drowned beauty like pilgrims seeking baptism in artificial waters. But mirages, by definition, disappear upon approach. How long before Page joins the Hohokam in the archaeology of the American Southwest—another settlement that outlived its reason for existence?
The Mathematics of Collapse
The numbers tell their own story, precise as tree rings but far more urgent. On February 22, 2021, Lake Powell measured 127.24 feet below "Full Pool"—a bureaucratic euphemism for the bathtub ring that marks the lake's aspirational height. At 38% capacity, the reservoir had shrunk to a shadow of its intended self, a liquid ghost haunting Glen Canyon's red-rock cathedral. But even this measurement understates the crisis, failing to account for the millions of metric tons of sediment accumulating on the lake bottom like the slow burial of dreams.
Geologist James L. Powell calculated that the Colorado River delivers enough silt, sand, and clay to fill 1,400 cargo containers daily—a ceaseless funeral procession of particles that once comprised mountains, mesas, and ancient seabeds. Lake Powell is disappearing from two directions simultaneously: evaporation steals water from above while sedimentation devours storage capacity from below. The lake shrinks toward its middle like a dying star, collapsing under the weight of geological time compressed into human decades.
The Bureau of Reclamation, with the optimism characteristic of federal agencies, estimated Glen Canyon Dam's lifespan at 500 to 700 years. Other voices whisper darker prophecies—some as dire as fifty years. The pessimists cite variables the bureau's engineers couldn't quantify in 1963: accelerating demand from sprawling cities, longer and more severe droughts driven by shifting climate patterns, more volatile storm systems that bring flood and scarcity in equally destructive measure.
A 2018 report by the Colorado River Research Group captured the mathematical poetry of the situation with an aptly metaphorical title: "It's Hard to Fill a Bathtub When the Drain is Wide Open: The Case of Lake Powell." Their data revealed the changing rhythm of the region's precipitation: wet years occurred roughly half the time during the twentieth century but only 25% of the time since 2000. The West's hydrological heartbeat has developed an arrhythmia that threatens the entire circulatory system.
The Hydraulic Empire
For Lake Powell and its downstream sister, Lake Mead, form a single hydraulic organism that sustains over 40 million people across the Southwest. Southern California's sprawling metropolises, Phoenix's glass-and-concrete ambitions, Tucson's desert suburbs, Las Vegas's neon oasis—all depend on this liquid lifeline threading through landscapes that evolution never intended to support such dense human populations. We have become the Hohokam writ large, masters of a more elaborate but perhaps more fragile desert empire.
The Arithmetic of Survival
Thomas Robert Malthus understood what both the Hohokam and we have learned through bitter experience: populations grow geometrically while resources expand arithmetically, and mathematics always wins in the end. His 1798 essay on population dynamics reads like prophecy when applied to water-dependent civilizations in arid lands—a theorem written in human suffering and hydraulic failure.
The Hohokam lived this equation for fifteen centuries, drawing their liquid lifeblood primarily from the Salt and Gila Rivers rather than the distant Colorado. During their expansion phases, population multiplied exponentially: villages begat more villages, successful harvests supported larger families, technological innovations in irrigation temporarily expanded the resource base. But the combined annual flow of the Salt and Gila remained stubbornly arithmetic, constrained by snowpack in distant mountains and the inexorable physics of evaporation. For a millennium and a half, Hohokam ingenuity postponed the reckoning through increasingly sophisticated canal networks, check dams, and agricultural techniques. They were buying time with technology, trading present abundance for future vulnerability.
When the megadroughts arrived in the fourteenth and fifteenth centuries, they served as what Malthus termed "positive checks"—the brutal correctives that restore balance through famine, conflict, and social collapse. The Hohokam's population had grown beyond the carrying capacity of their water system during good years, leaving no buffer for the inevitable bad ones. Their dispersal wasn't cultural choice but mathematical necessity, the desert's way of solving an equation that had grown too complex for the available variables.
We are performing the same calculation on a grander scale, with more sophisticated tools but identical constraints. The forty million people depending on Colorado River water represent our geometric population growth, spreading across landscapes from Los Angeles to Denver in defiance of hydrological reality. Our Glen Canyon Dam, Central Arizona Project, and All-American Canal constitute the technological fixes that temporarily escaped the Malthusian trap, allowing desert cities to bloom like improbable flowers in an ecological impossibility.
But the river itself remains bound by arithmetic limitations. Roughly 20 million acre-feet per year flow through the entire Colorado River system in a good year, perhaps 14 million in a drought year. No amount of engineering can manufacture water that doesn't exist, cannot conjure snowpack from empty skies, cannot reverse the fundamental mathematics of supply and demand in an over-allocated watershed.
The Malthusian crisis reveals itself in our reservoir levels, our groundwater depletion, our increasingly desperate water-sharing agreements that resemble peace treaties between hostile nations. We have reached the point where technological innovation alone cannot postpone the arithmetic of scarcity. Our dams are already built, our canals already dug, our cities already sprawling across landscapes that were never meant to support them. We are living on the interest of hydrological capital that is steadily diminishing.
Unlike Malthus's original focus on food production, water presents an even starker constraint. Agricultural yields can be improved through plant breeding, fertilizers, and farming techniques. But water is water—H2O in finite quantities, governed by precipitation patterns largely beyond human control. In the desert Southwest, we have reached what economists might call "peak water"—the point where demand permanently exceeds renewable supply, where growth becomes a zero-sum game played with an increasingly scarce resource.
The Hohokam faced their Malthusian crisis and chose dispersal over collapse, flowing like water toward more sustainable watersheds. Their empty canals filling with sand constitute an archaeological monument to the arithmetic of survival—proof that even the most hydraulically sophisticated civilization cannot indefinitely postpone the mathematics of resource limitation.
The parallel haunts like wind through empty irrigation channels. Both civilizations—theirs and ours—discovered abundance in aridity, learned to make the desert bloom through hydraulic engineering and collective determination. Both experienced population booms that transformed ecological possibilities into economic imperatives. Both developed sophisticated technologies for moving water across impossible distances, creating artificial rivers that allowed cities to flourish in landscapes that should have remained the domain of saguaro cactus and javelina.
The Hohokam's fate whispers across the centuries with the persistence of wind-carved stone: growth is not infinitely sustainable, technology cannot indefinitely postpone ecological limits, and when water runs short, civilizations don't simply adapt—they transform, disperse, or collapse. Their empty canals, slowly filling with desert sand, constitute an archaeology of overreach as much as achievement.
The Question of Tomorrow
Perhaps we are all Hohokam now—inheritors of hydraulic hubris, children of a civilization that confused engineering with permanence, that mistook temporary abundance for eternal entitlement. The question facing Page, Arizona, and the entire Colorado River watershed is not whether change will come, but what form our own dispersal might take.
Will we join the Hohokam in the desert's museum of vanished ambitions? Or will we learn what they could not—that true mastery of the desert lies not in conquest but in accommodation, not in making the landscape serve our desires but in shaping our dreams to fit the landscape's austere generosity?
The answer flows somewhere between the red canyon walls, in the space between what we want and what the desert can provide, in the eternal negotiation between human aspiration and the patient arithmetic of stone, sand, and sky. Lake Powell holds more than water—it holds the reflection of our own sustainability, as fragile and essential as morning dew on desert stone.
In the beginning, there was water. What comes next remains unwritten, flowing toward an uncertain sea.