Downtown Phoenix yields a rare archaeological find

By: Angela Cara Pancrazio ~ The Arizona Republic
October 15th, 2006

Streams of sweat rolled down Mark Hackbarth's face.

The archaeologist and his crew dug with shovels and hand trowels. Nearby, bulldozers rumbled under the hot summer sun on another corner of the downtown construction site for the new Phoenix Convention Center.

Because of tight construction schedules, Hackbarth had 30 days to excavate the remains of a prehistoric Hohokam village that had been preserved under the old Phoenix Civic Plaza.

When Hackbarth was called to the site at the end of July, he expected to find Hohokam ruins. But even after 20 years of archaeological work in the Valley, he never imagined the immensity of what he found.

Hackbarth uncovered three of the earliest known pithouses in the Phoenix metropolitan area, houses that were 3,000 years old. And as he dug, he kept finding more traces of the ancient civilization.

Today, thousands of artifacts from the dig rest in a Tempe laboratory as Hackbarth analyzes one of the Valley's greatest archaeological finds.

With downtown Phoenix engrossed in its biggest burst of construction since World War II, the discovery in its heart is a reminder of how far back the area's history goes.

The pioneers who first settled in Phoenix knew they were building on the ruins of a previous civilization. They named the city Phoenix to recognize the new rising from the old. But no one back in the 19th century would know how old the ruins they found in the dirt really were.

When the Phoenix Civic Plaza was built in the early 1970s, it sat on a cement slab, not a basement.

That left the ruins covered until this summer.

Surrounded by a culture fortified with glass, steel and concrete, the archaeologist circled the remnants of houses where people began living 1,000 years before the birth of Christ.

By the time Hackbarth and his crew from the Tempe-based archaeological firm Logan Simpson Design were finished in early September, they had discovered nearly 40 Hohokam pithouses. They had also filled 3,500 little brown sacks with artifacts and dirt to be studied for more clues about the people who first found a way to live in the desert.

An ancient people

The word Hohokam comes from the Akimel O'odham term for "those who have gone."

Their irrigation techniques and canal systems enabled them to farm, build a series of pueblos and thrive from the time of Christ until they vanished around 1450.

Four tribes today - the Salt River Pima-Maricopa, the Ak-Chin, the Gila River and the Tohono O'odham - trace their ancestry back to the Hohokam.

Remnants of the Hohokam are buried across the Valley, beneath the runways at Phoenix Sky Harbor International Airport, Arizona State University's Sun Devil Stadium and much of downtown.

Early in the 20th century, archaeologists mapped out Hohokam villages dotting the Salt River Valley. The area of old downtown Phoenix - between Central Avenue and 10th Street, Fillmore and Harrison Streets - rests on a village named Pueblo Patricio.

Last year during the planning stages for the construction on the northern part of the Convention Center, Phoenix's archaeologist, Todd Bostwick, pulled out old blueprints for the Civic Plaza site and noticed there was no basement, which meant there had been little excavation.

In the early 1990's, Bostwick and Hackbarth had excavated remnants of a Hohokam village next door to the old Civic Plaza in what is now Heritage Square at Seventh Street and Washington. Looking at the blueprints, Bostwick realized there was a good chance more pithouses might be found on the new site.

Pieces of the puzzle

Through the muggy heat of the monsoon season, Hackbarth and his crew methodically unearthed the site, often a fraction of an inch at a time.

Bulldozers had removed about 5 feet of dirt, and from there the tools were shovels and common garden trowels. They collected dirt in dustpans and sifted it through screens.

"Even these little pieces of pottery can be informative," said Bostwick as he nimbly tried to grasp a broken piece of pottery between his finger and thumb.

"We can look at what's inside the pottery and we can source the materials used to make the pottery and determine which village this pottery was made at; it might not have been made at this village."

Every fragment recovered by the team is bagged and marked with its pithouse location. After each piece is analyzed, the archaeologists will have an idea of how long people stayed at this location, how many lived here and what kind of crops they grew and traded.

Near the end of the monthlong dig, Hackbarth stood among rectangular and circular outlines of the pithouses.

"If you just look at this and say, 'Ah, this is a house,' that can only get you so far," Hackbarth said.

"But looking at what's on the floor, what's nearby, you understand more of how things were done in the past and you're not just seeing a nice artifact or seeing a wonderful house. You get to look more at their social structure, aspects of how they lived and died."

Death, disappearance

Human remains are part of a Hohokam village.

During the month of digging, the archaeologists found two burial sites. Out of respect and as part of an agreement with the tribes, all digging stopped immediately.

A medicine man from the Salt River Pima-Maricopa Community came and blessed the remains. Then they were removed and taken away for study to try to determine how they died. Remains and any pots or objects associated with the grave will later be returned to the tribe.

The Hohokam disappeared from the Valley in the 15th century. No one knows why.

Some archaeologists believe their farming could no longer sustain their growing population. Others think there might have been conflict among the villages. Or drought or floods could have diminished their canal system.

The ancient culture flourished in the Salt River Valley due to their canal system that diverted water from the Salt River. Over a span of more than 1,400 years, they created as many as 16 independent canal systems. Some of the canals, more than 1,000 miles of them, were 50 feet wide. The Hohokam moved tons of earth and carved out their canals with stone and wood tools.

Winds and rain covered the abandoned villages with dirt and preserved the ruins.

In 1929, Phoenix was the first American city to hire a full-time archaeologist, who helped preserve the Hohokam village of Pueblo Grande. Bostwick was hired as the city's fourth archaeologist in 1990.

Whenever a developer or the city wants to put up a new office building or high-rise, Bostwick studies whether anything of archaeological or historic significance will be disturbed. During the 1980s, the city adopted a historic preservation ordinance that included protection of its archaeological resources.

In recent years, cities and counties around the state have adopted similar ordinances. But it's still not enough, said John Madsen, associate curator of archaeology at the Arizona State Museum.

Around Arizona, looting and vandalism was so widespread at archaeological sites that in 1990 Arizona passed legislation more stringent than previous burial laws.

It is illegal to knowingly disturb any buried human remains or burial artifacts on public or private land, including backyards, without permission from the state.

Ravaging of sacred Indian burial grounds by pot hunters continues, said Madsen, especially in the far reaches of Arizona where it is often impossible to police and prevent the thievery.

"Everyone that's buried has a large number of vessels buried with them."

Madsen said the looters know where the burials are and go after them.

"They wreak havoc, the research potential is gone forever and they are disturbing human remains."

The continuum

After the dig, Hackbarth and archaeologists Mary Ellen Walsh and John Rapp began studying the soil and fragments at their Tempe lab.

One morning, Hackbarth ran his fingers over a large trough-shaped rock. There are tiny pockmarks created by grinding saguaro seeds and corn kernels into the basalt.

Walsh eyed a pottery shard with a microscope.

"This is like my dinner plate and someone used this pottery," she said.

Hackbarth lifted a heavy rock hollowed out at the center like a doughnut. He explained that the Hohokam used such rocks as counterweights on the end of their digging sticks, making it easier to puncture the soil.

Because these remnants are from a Phoenix site, the artifacts will be stored at a climate controlled and secured vault at the city's Pueblo Grande Museum. It will probably take three to five years to complete the archaeological survey for this dig.

Before the dig, Hackbarth and Bostwick thought the Hohokam people lived at this downtown site only seasonally. But the number and size of the pithouses suggest that they lived here more permanently.

Their biggest discovery was uncovering remnants of the late Archaic people, those who came 1,000 years before the Hohokam.

Archaeologists believed these were hunters and gatherers, nomadic people who roamed on the edges of the Valley hunting and living along small streams.

Settling so close to the river means they needed water to irrigate their fields; they weren't just hunters and gatherers, they were farmers too.

Watching the Arizona Diamondbacks or Phoenix Suns or working in a downtown office cubicle, it's tough to imagine that the Hohokam settled at this site because it was higher than the vibrant river nearby where they fished the streams and harvested corn and cotton.

And that they hunted birds and mule deer in a thick mesquite forest that covered the landscape from where Chase Field is today to McDowell Road.

All of the pithouses are gone now, removed by construction crews digging the 40-foot-deep foundation for the new convention center.

But as Phoenix rises once again on the village of Pueblo Patricio, the mystery of the ancient civilization is far from over.

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