Montezuma Well
Near Sedona, Arizona
A few miles northeast of the cliff dwelling that shares its name, a perfectly circular pool fills a collapsed limestone cavern in the Arizona desert. Montezuma Well is three hundred sixty-eight feet across and fifty-five feet deep, and it releases roughly one and a half million gallons of warm, mineral-rich water every single day, has done so for thousands of years, and will almost certainly continue long after anyone driving this highway is gone.
The geology behind the well reaches back roughly eight million years, when the Verde Valley lay under a shallow lake. When that lake dried out roughly two million years ago, it left a thick bed of limestone. Underground streams slowly dissolved caverns within that stone, and eventually one roof collapsed, opening the sinkhole that fills today with water rising from deep aquifers at a constant temperature around seventy-six degrees Fahrenheit.
The water's chemistry is extraordinary: extremely high in carbon dioxide, nearly devoid of oxygen in the deeper zones, and home to a community of creatures found nowhere else on Earth. Fish cannot survive in it. Instead, the well contains at least five endemic species, organisms that evolved here and exist nowhere else, including the Montezuma Well springsnail, a water scorpion, a unique leech, and the tiny amphipod crustacean that the leech feeds on exclusively. Scientists regard it as possibly the highest concentration of endemic species in any single spring in all of North America.
The Sinagua people recognized what they had. By the twelfth century they were living in cliff dwellings around the rim and had constructed an irrigation system that drew water from the well through hand-cut channels still visible in the rock. They grew cotton, corn, and beans in fields fed by water that required no rain and never ran dry. The Hohokam had farmed here before them, and the Yavapai after. The well has sustained human life continuously for at least eleven hundred years, a fact that dwarfs almost every other claim this highway corridor can make.
