A Hidden Ancient Culture

Archeologist Gina Gage pulls a fragment of red pottery decorated with black stripes from the ground and begins to explain how it might fit into the history of one of America’s most advanced and mysterious ancient cultures.

Then her voice is drowned out and the shard trembles as a 747 takes off a few yards away and another of the seven jets lined up on the taxiway revs up for departure.

Gage and her team have been excavating an approximately 500-year-old Hohokam farm site before it gets paved over in an expansion of Phoenix’s Sky Harbor International Airport.

Despite its reputation as a city born after the discovery of air conditioning, modern Phoenix sits atop relics from the past 2,000 years.

What’s being done to preserve that heritage from rapid urban growth makes the city a leader nationwide in conservation.

Phoenix is one of a handful of U.S. cities, including Boston; New York; Alexandria, Va.; and St. Augustine, Fla.; to have a full-time archeologist on staff. Phoenix’s archeologist position was established in 1929 and is thought to be one of the first.

“To have a city archeologist, that’s an excellent example of how the state is working,” said James Walker of the Archeological Conservancy, a nonprofit group dedicated to preserving archeological sites nationwide. “Arizona is leading the country in these areas.”

As Phoenix’s archeologist, it’s Todd Bostwick’s job to oversee nearly 700 sites, including Gage’s dig, in a sprawling metropolis covering 470 square miles.

“It’s not like it’s some quiet little space where you do what you do,” Bostwick said. “You’ve constant activity all around. And we go from 10-block projects to five feet of sewer line.”

The area’s archeological remains are seldom eye-catching, consisting mostly of adobe buildings and canals built by the Hohokams, who lived in the Salt River Valley from AD 1 to 1450.

But they constitute pieces in an unsolved puzzle: What caused the Hohokam and other Southwest people to suddenly disappear or devolve to very simple societies in the 15th century?

“Most of what’s excavated by archeologist is information, not the spectacular findings that people think of,” said Linda Mayro, the cultural resources manager for Pima County in southern Arizona.

The Hohokam turned the harsh desert, with about 7.5 inches of rain a year, into farmland by building about 1,000 miles of canals.

Then, about 1450, they vanished. Archeologists are still wondering why.

That makes it even more important to preserve any clues, and in Phoenix, zoning law is designed to do so.

Regardless of whether the land to be developed is public or private, if the project includes rezoning the developer has to do an environmental impact review.

Two years ago, the review was broadened to include cultural resources, so “project managers now have to think archeology,” Bostwick said.

Further, since federal law mandates that construction stop if human remains are found, most developers plan archeological diggings before starting.

At real estate company Del Webb’s latest development, the 6,000-acre community of Anthem about 40 miles north of Phoenix, that attitude paid off when an almost undisturbed Hohokam farming site was found dating to 1100, said archeologist Lynn Neal.

The developer donated the 26-acre site to the Archeological Conservancy, which is rare since most sites aren’t preserved because construction can’t be moved. In those cases, it becomes the archeologist’s job to salvage as much information as possible before the bulldozers come in.

Funding for that excavation is the developer’s responsibility, Bostwick said. In projects like the airport renovations, it might amount to $1 million, though that’s only 1% of the construction cost.

With the increase in urban sprawl, however, preservation is becoming a must.

“As development has accelerated, more sites are being destroyed, which makes others all the more valuable,” Mayro said. “Once they’re gone, they’re gone forever.”

Like the Hohokam, whose name is modern Tohono O’Odham for “those who have gone.”