Andy Davis

aldavis@press-citizen.com

Armed with a laser imaging scanner, a team of University of Iowa faculty, students and state archaeologists on Monday embarked on an underground educational excursion.

The group delved into Iowa City's man-made "beer caves," a system of tunnels on the city's north side. The team explored the portion of caves located about 30 feet below what used to be the Union Brewery, now the Brewery Square Building.

Adam Skibbe, Geographic Information Systems administrator in UI's Geographical and Sustainability Sciences Department, led the scanning efforts. Skibbe said the LIDAR scanner — a detection system that uses light from a laser and works on the principle of radar — will collect points of data that will be patched together to render a high-definition, 3-D image of the caves.

"We'll do six scans, and each takes about 30 minutes to do. We'll probably end up with several million data points," Skibbe said. "The data comes back as a massive cluster, which we reconstruct as a landscape. Eventually we plan to make a fly-through video and possibly something you could use an Oculus (virtual reality headset) to explore."

Early renderings of Iowa City beer cave scans

Mark Anderson, a research archaeologist with the Office of the State Archaeologist, came along for the trip and said LIDAR technology is typically used by aircraft to map the landscape of the ground below.

Monday's work was the first time in the state the technology was used to map caves, Anderson said.

"What we wanted to do was put together a multi-departmental team that could accomplish the work and then, just as importantly, interpret it for the public," Anderson said.

The work will not only create a tangible product viewers can interact with, he said, but will lead to talks and presentations about the project and the history of the caves.

Located below Linn and Market streets on the city's north side, the caves were once used to ferment and then transport beer starting in the later half of the 1800s. Marlin Ingalls, an archaeologist and architectural historian with the Office of the State Archaeologist, also was in tow during the mapping to provide historical context.

Ingalls said the caves were completed sometime around 1857, and were likely built by German masons. Builders used millions of hand-made bricks fired in wood stoves to build an arch system in a centuries-old Roman building style.

There are more caves along Market and Jefferson streets that once were used by two other nearby breweries, City Brewery and the Great Western Brewery.

"This was a time people were living here, and Iowa was just barely a state," Ingalls said. "At the time, Iowa City was really the last stop on the railroad ...and you could get a bucket of beer for a nickel."

Skibbe and four students worked to map the main corridor and a smaller cave at the back. The cave at the back has a channel in the floor that was once filled with water so kegs could be floated from one end to the other.

Near the entrance shaft at the entrance of the main corridor is another cave that holds coils of rusted steel left by kegs that were destroyed by fire.

Ian Dunshee, an undergraduate studying anthropology and GIS, said he had visited the caves a few months ago when the team descended to plan the project. At that time, he said, the caves were filled with about a foot of water that was pumped out.

Dunshee said he has a particular interest in using LIDAR and GIS-related technology for archaeological sites.

"If you dig up a site and end up destroying something, you can't research what you've destroyed," Dunshee said.

He explained that LIDAR technology allows archaeologists the ability to take detailed scans throughout a dig to preserve the various stages of the excavation. Those scans preserve the "before, during and after" phases of a dig that offer future points of reference if they are needed.

Skibbe said he may need to return to the caves if there are gaps in the imaging, but the final product will be posted online and will provide those who are not able to climb down into the caves or who are too claustrophobic the chance to experience a piece of Iowa City brewing history.



Reach Andy Davis at 319-887-5404 or at aldavis@press-citizen.com, and follow him on Twitter as @BylineAndyDavis.