Carnegie Mellon University
August 23, 2013

Staying Afloat: DiPietro Studies Environmental Impact of Monongahela Towboats

Staying Afloat: DiPietro Studies Environmental Impact of Monongahela Towboats

CEE PhD candidate Gwen DiPietro is studying the environmental impacts of towboats on the Monongahela River. “In many ways, the rivers in Pittsburgh are out of sight, out of mind; people who live here are only really aware of the rivers when they’re driving over them,” says DiPietro. “Many people don’t realize that the rivers are still highways that move a tremendous amount of materials.”CEE PhD candidate Gwen DiPietro is studying the environmental impacts of towboats on the Monongahela River. “In many ways, the rivers in Pittsburgh are out of sight, out of mind; people who live here are only really aware of the rivers when they’re driving over them,” says DiPietro. “Many people don’t realize that the rivers are still highways that move a tremendous amount of materials.”

Hear the words “industrial transportation,” and you’ll likely think of semis, trains, or airplanes. But what about boats? Though many Pittsburgh residents don’t know it, river transportation is a key component of industry in the Pittsburgh region. Thirty million tons of materials, eighty percent of which is coal, are transported on Pittsburgh's rivers by towboats every year, and their ability to traverse the rivers is dependent on a hundred-year-old system of locks and dams. So what happens if these locks fail? 

CEE PhD candidate Gwen DiPietro wants to find out. DiPietro, who is advised by Duquesne Light University Professor Chris Hendrickson and Professor H. Scott Matthews, is working to quantify the environmental impact of the towboat fleet on the Monongahela. In the event that one or more of the antiquated locks at Elizabeth or Charleroi fail and river transportation is transferred to other modes of conveyance while the system is repaired – a process that DiPietro estimates could last a year – knowing how such a change would play out environmentally and economically would be invaluable. “There are a lot of efficiencies associated with using the rivers to transport materials, and the congestion effects on the region could be significant if one of these antiquated locks were to fail,” DiPietro explained. “There is a significant likelihood that one will fail.”

The advantages of river transportation

The Monongahela’s towboat fleet consists of roughly one hundred boats of varying types and sizes. DiPietro noted that a standard towboat pushing fifteen barges has the carrying capacity of 885 trucks or more than two one hundred-car trains. “The working theory is that towboats are more efficient than other conveyance methods because they require less fuel and are therefore associated with lower air pollution levels,” she said. “I’m exploring whether this theory is true for the Monongahela’s towboat fleet.” Studying one boat at a time, DiPietro is gathering information about each boat’s engine and assigning the boat a compliance status based on its fuel efficiency. She will then combine this information with existing records from the Army Corps of Engineers which note the exact times particular boats traveled through each lock in 2010. 

While many large studies have been conducted on the environmental and economical impact of river transportation, DiPietro’s is the first to focus so narrowly on the Monongahela and the actual vessels that work there.  “These national studies don’t tend to reflect the realities of a specific place,” she explained. “I’m trying to develop a methodology that makes it real for Pittsburgh – that is specific to the actual boats and the trips they make, and illustrates the impact of a particular lock failing.” 

Implications of DiPietro’s research

So what does this study mean for Pittsburgh? For starters, DiPietro’s findings could be valuable ammunition in the argument to fund the stalled upgrades of the Monongahela’s vulnerable locks and dams. “Right now, the rivers are not used at full capacity because the locks are so slow and unreliable,” she explained. “If it’s true that towboat transportation is more efficient than rail, then replacing these locks and dams and transferring more materials from rail to barge could be a way to improve air quality.” More broadly, having accurate data on the air pollution associated with river transportation will aid policymakers in making informed decisions about Pittsburgh’s infrastructure and industrial policies.

For DiPietro, a Pittsburgh native who completed her bachelor’s in chemical engineering in 1982, researching the Monongahela towboats is an opportunity to draw on her extensive experience with environmental sustainability. As Lead Engineer at the Center for Sustainable Solutions, she worked with U.S. Army garrisons to identify and implement strategic sustainability goals to ensure their long-term functionality. Prior to that, DiPietro worked as a team leader at the U.S. Environmental Protection Agency, where she focused on the characterization and regulation of hazardous waste, and the development of public policies to maximize recycling industrial by-products and construction and demolition debris. “Everything that I’ve done in my career has been associated with the environment in one way or another,” she said. “A couple of years ago, I decided it was the right time for me to fill in some gaps in my education, and I came to Carnegie Mellon.”

DiPietro is happy she returned to school, noting that she enjoys working with the younger engineers. “For me, the most rewarding thing about conducting research in the CEE department is asking a question that has not been answered yet and coming at it from a new angle,” she said. “Many people don’t realize that our rivers are still highways that move a tremendous amount of materials. I hope that my research will address issues on the rivers.”