Four Corners – In national parks and historic sites across the Southwest, federal conservation experts are pouring tons of dirt over 1,000-year-old ruins, reburying them in a desperate attempt to preserve the ancient dwellings and the information they hold about past lives.
Archaeologists have lost too many battles against wind, water and gravity, they said. At Chaco Canyon, Aztec Ruins, Chimney Rock and other popular sites, walls are crumbling and ceilings are collapsing faster than they can be repaired with mortar and epoxy.
By reburying sites – a process called reverse excavation, or backfilling – conservators put ancient structures back in a sort of suspended animation, where delicate mud mortar, ancient plaster and intricate stonework can hide from the elements.
But reburying also conceals ruins, perhaps forever, from the public’s eye. Hundreds of thousands of people pay fees and taxes to visit ancient Southwestern ruins every year.
“I know that, archaeologically and scientifically, there is a very valid argument that burial is the best option for preservation, and the cheapest,” said Glenn Raby, a geologist at Chimney Rock Archaeological Area near Pagosa Springs. “I guess the question you have to ask is, ‘Preserve it for what?”‘
Dabney Ford, an archaeologist at Chaco Culture National Historical Park in New Mexico, manages up to 12 Navajo and Pueblo men who help the park maintain hundreds of thousands of stone structures. The masons replace eroded mud mortar with concrete, build modern roofs over ancient stones and close trails when crumbling walls threaten visitors or staff.
But that constant stabilization turns ancient walls into modern reconstructions, Ford said.
So this summer, workers will dump tons of desert dirt to protect the original architecture in Chaco’s Pueblo del Arroyo, covering the lower walls to keep wind, water and temperature swings at bay.
At Aztec Ruins National Monument in New Mexico, they’ll continue work on the National Park Service’s largest project to date: the reburial of more than 100 rooms painstakingly excavated a century ago.
And at Chimney Rock, experts will soon decide whether to cover a great house and a kiva, the structures that draw virtually all the site’s annual 10,000 tourists.
At a few Southwestern sites, backfilling has gone on quietly for several years, said Todd Metzger, a Park Service archaeologist in Arizona.
Now it’s either happening or proposed at almost all federal ruins because of what he calls a “crisis situation” in stabilization.
Metzger is preparing an agency document that lays out some of the questions managers should ask when considering how best to protect ruins. Backfilling is often the best option, he said.
Gary Brown, archaeologist at Aztec, stands on a rise that commands a wide view of the sprawling pueblo ruins that are 900 years old. Nearby, workers spread gravel on a newly refurbished modern roof for the Great Kiva.
The giant circular room has been completely reconstructed since work began on it in 1933.
“The significance of the site lies in the ruins, not in the reconstruction,” Brown said. “If a wall falls down, we don’t rebuild it.”
Most of Aztec’s 400-plus rooms lost their roofs hundreds of years ago.
Moisture moves in and gets trapped in narrow rooms and between walls, where it eats away at sandstone masonry.
“We’ve reached a point that’s considered to be intolerable by many preservationists,” Brown said.
So Aztec workers are backfilling, buttressing some walls with earthen berms, covering others. In areas, they have used conveyor belts to sift dirt into tricky spaces, and workers tamp down each layer by hand. Crews install plastic drainage pipes to pull moisture out of backfilled rooms. They test fill dirt for salts that could harm old building materials.
“I have mixed feelings,” Brown said. “It’s no longer possible to get back into these rooms.
“In a perfect world, it would be nice to leave the structures open. It’s a very beautiful ruin.”
Norbert Grona from nearby Bloomfield has toured Aztec Ruins many times and has no qualms about the backfilling project, he said.
“They’re saving this place for future generations,” Grona said.
At Colorado’s Chimney Rock, managers are considering a variety of options. One would put the site’s signature ruins underground to protect the crumbling structures.
“Yes, backfilling will preserve it forever. That said, I am not a proponent,” said Gary Fairchild of the U.S. Forest Service in Pagosa Springs, which manages the archaeological site.
Chimney Rock’s visitors come for two reasons: the Great House Pueblo and the Great Kiva.
“Without those, no one will come,” Fairchild said.
Late this year or early next year, the Forest Service will decide whether to leave the site as it is, fill it in or find some middle ground.
Fairchild and many of his colleagues hope for a partial backfill, which would protect the ancient bottoms of walls but leave exposed a “foreman’s outline” of the buildings.
Workers would need to continue constant stabilization work on the upper walls, he said, but most of those walls have already been extensively reworked in the past several decades anyway.
That’s also true at many of Chaco’s ruins.
Harold Suina of Cochiti Pueblo repositioned unstable stones on one high wall at the ancient site, using mud mortar, sand and special glue to secure them.
Suina said he’s happy the ruins are on display so that people can see the achievements of the ancestral Puebloans.
But year after year, the park has lost funding for stabilization. Crews have dwindled to one, with about a dozen men, most of them hired only seasonally.
Lewis Murphy Jr., a Navajo, said his crew and others have filled in about one-quarter of the rooms at Chaco, some with just a couple of feet of dirt, others with 6 feet.
John Keller, a Californian who visited Chaco in late April, said he found the work quite natural in appearance.
“But it’s too bad you can’t protect sites without taking away from the height of the ruins,” he said. “That’s one thing that makes Chaco so special – the tall rooms.”
Keller said he would propose an alternative preservation plan.
“They should just pick one ruin at a place and bring it back to its heyday, completely restored so people can see what it was really like,” he said. “Then they should make the rest off-limits to everybody.”
Staff writer Katy Human can be reached at 303-820-1910 or khuman@denverpost.com.
Staff writer Electa Draper can be reached at 970-385-0917 or edraper@denverpost.com.
