On May 20th and 21st I had the pleasure of leading a public archaeological survey at the site of the historic military site, Fort Howard, in downtown Green Bay. Thanks to special permission from Brent Weycker, owner of Titletown Brewery, we were allowed to set up a survey area behind the brewery along the railroad tracks. Based on historic maps and previous research, this area is thought to be the location of the southeast section of the former fort.
More than one hundred people came out both days to learn about the fort’s history and the technology being used to locate it. Although we know the approximate location of the fort we do not know exactly where the stockade or any of the buildings stood. The main technology used in the survey was the museums’ Ground Penetrating Radar (GPR).
GPR is a technology that uses radio waves to “look” into the earth without digging. The radio waves bounce off of buried objects and are captured on a computer chip. After the survey area is mapped the data can be sliced in layers using special computer software. This can reveal patterns that might give clues to the size and shape of buried features and how deep these features are located.
Over the course of the 2 days, 3 survey grids were collected with a total area of 5,433 cubic feet. The depth that the GPR was looking was just over 6 feet deep. After processing the data, it was clear that there is large amount of disturbance in the first 2 feet or so, likely from the past hundred years of railroad activity. However below 2 feet things got interesting.
Around 3 feet below the surface, a series of anomalies appeared in all of the survey grids we collected. Once the grids were stitched together at the same depth, a pattern emerged that strongly points to these anomalies as being human-made and possibly associated with the historic Fort Howard. At this time we cannot confirm that what the GPR is showing us is the fort but if there was to be a controlled archaeological excavation, we can recommend an exact location to dig. Known as “ground truthing,” an excavation would prove if what we’re seeing are the remains of wall foundations or something else.
In the meantime, we hope to continue surveying the area behind Titletown Brewery, and hopefully beyond, in order to piece together a much larger understanding of Fort Howard. If the patterns in the data below one meter continue, then it will make for a compelling case that we have located the foundations of the fort that made Green Bay American.
I will be presenting the findings of our GPR survey at a special Hardcore History event on August 9th at 6pm. If you want to learn more about the history of the site and Fort Howard’s influence on Green Bay visit our current exhibit Life and Death at Fort Howard open through April 2017!