Posted on August 19, 2024
Joe Dunbar and Benjamin Breland, research geologists for the U.S. Army Engineer Research and Development Center, working alongside the U.S. Army Corps of Engineers Pittsburgh District, collect soil samples during an archaeologic and geomorphic shoreline survey along the Monongahela River between Elizabeth and Charleroi, Pennsylvania, Aug. 6, 2024. The U.S. Army Corps of Engineers Pittsburgh District conducted a shoreline survey to protect potential cultural resources. Cultural resources can include archaeological artifacts or historical sites. Recently, the Pittsburgh District lowered the river level by approximately two feet on a portion of the Monongahela River after breaching a fixed-crest dam in Elizabeth. As part of the Lower Monongahela River Project, the removal requires the district to mitigate and avoid damage to sites with cultural value. Lowering the river exposed shorelines along approximately 18 miles of the Monongahela, rendering sites with potential cultural or historical value exposed and more vulnerable to the elements. The team surveyed soil samples and sediment layers and recorded any archaeological artifacts found along the way to designate sites of potential cultural significance. (U.S. Army Corps of Engineers Pittsburgh District photo by Michel Sauret)
PITTSBURGH – As Joe Dunbar stepped from the boat onto shore, his leather shoes sunk immediately into the mud.
His geologist colleague, Benjamin Breland, walked beside him with the same result. The soft soil suctioned around their soles, each footstep sinking them inches into the sloppy shoreline.
“That’s some muddy work,” someone said from the boat, hesitant to step off the vessel to join them.
“It’s what we do,” Dunbar responded, joking about his commitment to the job.
The geologist duo had traveled from the U.S. Army Engineer Research and Development Center (ERDC). They flew from Vicksburg, Mississippi, to the Pittsburgh area to study the Monongahela River’s topography and geology.
“For the Corps!” Dunbar added, gesturing an “onward” motion with his arm with dramatic flair. The mud clung to his boots with each boggy step.
The U.S. Army Corps of Engineers Pittsburgh District invited the geology research team to assist with a shoreline survey. Although the Pittsburgh District has geologists on staff, they tend to specialize in conventional engineering geology studies involving rock coring, soil sampling, groundwater, and hazardous and toxic waste applications.
This trip was different, focusing on the past not future construction. The survey involved a multidisciplinary focus consisting of archaeology, geomorphology, and a background in geographic information systems (GIS) technology.
“This is very specialized work,” Dunbar said. “We are so lucky to get to work on some really interesting studies, and this project is one of the most interesting.”
The team’s survey will produce a report with geomorphic and archaeological data aimed at protecting possible cultural resources located along the Monongahela River. Once the corps completes the report, it will provide the material to Pennsylvania’s State Historic Preservation Office, also known as the SHPO.
“As a federal agency, we have the responsibility of assessing the effects our projects might have on historical sites or cultural resources,” said Michelle Zulauf, the archaeologist and tribal liaison for the Pittsburgh District.
Cultural resources can include anything from archaeological artifacts, historical structures, traditional cultural properties, historically significant landscapes, and more, Zulauf said.
“Under our programmatic agreement for the Lower Mon Project, we are committed to address and identify all the archaeological and historical sites that are within any aspect of our federally-funded projects,” Zulauf said.
Recently, the U.S. Army Corps of Engineers began removing a fixed-crest dam from the river near Elizabeth, Pennsylvania. Removing the dam lowered the waters along a portion of the Monongahela River by approximately two feet, affecting an 18-mile stretch of the river.
Lowering the river exposed shorelines with potential cultural or historical value, rendering them vulnerable to the elements or intruders. As part of the Lower Monongahela River Project, the dam’s removal requires the corps to mitigate and avoid damage to sites with cultural value.
“Now these sites could be exposed to erosion or looting,” Zulauf said. “I feel like it’s our responsibility as the federal government to protect the nation’s heritage and preserve these sites for the future.”
Two teams, one from ERDC and the other from the Pittsburgh District, joined for the work. They include geologists, archaeologists and historians, plus a boat captain. The group spent the day visiting and recording dozens of sites, stepping off and on the boat multiple times to investigate each area.
“This has been one of the coolest trips,” Dunbar said, who has a Ph.D. in geology and has conducted geomorphic research on the Mississippi River and around the country in his 46-year career.
“It’s just been so enjoyable,” he said about studying the Monongahela River for the first time.
The geologists measured shorelines, collected soil samples and tested sediment layers, while the historians and archaeologists recorded artifacts discovered along the way. They scribbled details into their field notebooks to help identify sites of potential cultural significance.
At most stops, the geologists dug into the soil with shovels, augers or other handheld tools. On a few occasions, historians spotted pieces of pottery, clay jars or even broken bottle jug necks. Their job was not to determine which people groups might have left those artifacts behind, nor determine time periods. A broken piece of clay might have been there two months or two hundred years. Their goal was to simply record the data. Their findings could lead to future study or excavation.
If an archaeological site is discovered, the Pittsburgh District will develop a mitigation plan to protect the area from further damage, Zulauf said.
“I’m a trained archaeologist. I’ve always had a passion for preservation and curation. The Pittsburgh District has so much land and opportunity for stewardship,” Zulauf said.
These riverbanks are potential sites where historic or even prehistoric Native Americans and other settling populations may have lived once.
The boat ride lasted approximately 10 hours as the crew spotted and surveyed critical shores along the river. The geologists had come with pages and pages of oversized river maps and charts, some dating back to 1833, to identify historical changes in topography.
After all, it was not just the recent dam removal near Elizabeth that affected river levels. Private industries constructed the first locks and dams on the Monongahela in 1838, which raised river levels. Later, the U.S. Army Corps of Engineers took over responsibility for navigation locks, supporting commercial navigation for more than a century. Some artifacts found on the newly exposed shorelines could date back hundreds of years.
“This landform has been stable through time,” Dunbar said, which means it is possible people inhabited the banks before the river levels rose in the 1800s.
Whenever Dunbar spotted a large rock along a shore that was mainly formed of sand or fine soil, he asked, “I wonder how that big rock got there,” hinting at evidence of man’s involvement that an untrained eye would miss or ignore.
Dunbar said the topography and soil can offer a lot of clues about the people who might have lived upon this land once. Each soil sample provided clues about the past.
“There’s a lot you can tell by different types of soil if they’re potentially habitable or not, whether in recent past or in the really distant past,” Zulauf said.
For example, geologists look at soil permeability, meaning how well it will drain, to determine how inhabitable a piece of land might be. If soil has low permeability, it drains more slowly and has a higher chance of flooding. They also look at the topography, land slope, proximity to water, agricultural opportunities, soil or mineral types, all offering little hints.
“Usually, earlier populations would settle near a tributary, but they would live on high ground to avoid flooding from inconsistent river elevations and find places near food sources,” Dunbar said.
Hunters and gatherers used the river for fishing and looked for trees and bushes with berries, fruit and nuts.
After a long research day, the team closed their notebooks and packed away their tools. Translating their findings into a full report may take several months of homework, cross-referencing charts, and verifying source data.
There is no certainty whether the new shorelines along the Monongahela River offer new historical insight, yet. For now, the team has only gone a few inches deep into the soil with their shovels and boot soles. It is too early to get excited, but future excavations could lead to more findings as they dig deeper into the earth.
“I enjoy thinking about the future,” Zulauf said. “What are people going to find? What were we able to preserve for them that might become something really significant down the road? We don’t have to excavate every single site. We can preserve them for when better technology down the road can uncover more.”
