With an interdisciplinary spirit, Lafayette supports Bushkill Creek’s restoration

By Bryan Hay

Freshwater mussels perform a valuable environmental service, keeping streams and rivers clean by absorbing heavy metals and filtering out pollutants, silt, and algae that otherwise would harm fish and riverine habitats.

All they need to do is hitch a ride on the gills of fish, jump off when they reach upstream beds, settle among rocks, mud, and sand to complete their metamorphosis, then get busy doing their essential ecological work.

However, their egress into the Bushkill Creek, a watershed encompassing 80 square miles from Blue Mountain to the Delaware River in Easton, has been blocked for more than 100 years after a series of dams was constructed for milling. 

But that’s about to change as a Lafayette-supported project led by the Wildlands Conservancy and involving numerous government agencies and conservation organizations will remove several dams to restore freshwater mussels and improve the health of this creek that supports a large diversity of plant life and aquatic and land-based species.

Nearly 20 years in the making, the project emerged from a legal settlement stemming from a 2005 coal ash slurry spill at a coal-fired power plant on the Delaware River about 10 miles north of Easton. The nearly $1 million mitigation settlement, overseen by Delaware River Basin Commission, Pennsylvania Department of Environmental Protection, and Pennsylvania Fish and Boat Commission, was mostly designated to fund mussel restoration and removal of the Bushkill Creek dams, including the one owned by Lafayette behind its Film and Media Studies building on North Third Street. 

Separately, the Wildlands Conservancy secured nearly $2 million in grants and other funding to support the Bushkill project. 

On Friday, July 7, using a hydraulic pick, crews started to safely remove the Lafayette dam, the first and most critical of a series of dams upstream of the confluence of the Bushkill and the Delaware. The dam at the Simon Silk Mill will be removed later this summer, and the Easton-owned dam, between Lafayette’s and Simon’s dams, will come down next summer. The Wildlands Conservancy removed two additional dams on the Bushkill Creek in 2021 and plans to remove a fourth upstream dam and install instream habitat at its Binney & Smith Preserve as funding becomes available. 

For the Lafayette community, the project has provided an opportunity to demonstrate environmental stewardship and offered rich interdisciplinary collaborations, bringing together faculty and students in biology, civil and integrative engineering, geology, and economics. For almost 15 years, they have examined and studied the effects of removing the dams, gathering valuable data that will support and inspire similar projects in the future. 

“Lafayette College has done a tremendous job engaging their students in the many aspects of the project and helping them gain real world experience,” says Kristie Fach, director of ecological restoration with the Wildlands Conservancy.

“Their years of stream monitoring have provided a detailed record of pre-project conditions and stream ecology,” she says. “We are excited to be able to compare and quantify the benefits of the dam removals and use this as a model for future stream restoration projects.”

Since 2010, students of Megan Rothenberger ’02, associate professor of biology and chair of environmental programs, have been wading in the Bushkill collecting pre-dam removal data in preparation for the dam removals. 

“When I was a student here, there weren’t as many interdisciplinary programs as there are now. Things were far more siloed and divisional,” she says. “The Bushkill Creek dam removals are a really good example of a problem where we really needed all of these different perspectives and experts. 

“We needed all that different expertise to actually address the full scope of the issue. It isn’t just a science problem. It isn’t just an economics problem,” Rothenberger adds. “It’s really been cool. The students who have worked on this project in my lab over the years have interacted with other departments, including engineering and geology. It’s the kind of stuff I love and what makes the Lafayette experience so unique.”

In addition to recognizing the value of dam removal to restore natural flows, Rothenberger and her students have come to recognize that freshwater mussels represent a freshwater version of coral reefs, burrowing into sediment and helping with nutrient recycling and decomposition.

“They create a sort of structure, the way corals do,” she explains. “They create habitats that are used by other aquatic freshwater species. They’re considered a keystone species in riverine and stream habitats. Nobody really thinks about mussels, because they seem uninteresting. They’re just there. It’s not like they move around like a fish or a turtle or a frog. But they’re one of the most threatened species of animals actually. And the main threat to mussels is dams.”

Mussel larvae are parasitic, temporarily. They attach to the gills of fish that swim up and down rivers and streams. Once they get upstream into a new habitat, they drop off the gills, never harming their host, and grow into adults. Long lived–mussels can live up to 200 years–the bivalves in the Delaware River below the confluence with the Bushkill are abundant. 

“But if dams are blocking the streams and the fish aren’t able to move up and down, then neither can the mussels,” Rothenberger says.

Eurnett Christopher ’25, who’s pursuing a degree in environmental science with a data science minor, joined Rothenberger’s lab in spring to study the effects of low-head dams on the physical and ecological structure of Bushkill Creek.

“This effort is important since mussels are a vital part of the freshwater ecosystem,” she says. “Dam removal will restore the natural flow regime and allow for migration of fish species. Additionally, mussel restoration efforts will likely improve water chemistry and restore aquatic food webs in the Bushkill Creek. Our pre- and post-removal monitoring will allow us to assess this.

“I believe that Lafayette’s initiative to remove these dams will inspire other community members to remove their dams,” Christopher adds. “Believe it or not, we rely heavily on the ecological and economic services provided by freshwater mussels. Restoration of these extraordinary creatures is just the beginning for the restoration of Bushkill Creek. It’s been a valuable Lafayette learning experience.”

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Mussels, dams, and economics 

Hongxing Liu, assistant professor of economics, and her students have been looking at the socioeconomic aspects of the dam removal project.

“We’re looking at the housing values around the creek, to see how the dam removal is capitalized in the housing market. Basically, when the water quality is better, the housing prices are higher,” she says.

They’ve also been surveying Easton residents to gauge how their behaviors and activities have been influenced by the dam removals, considering the changes in aesthetics, water quality, and recreation.

“These are things that you can’t directly measure from scientific measurements of water quality,” says Liu, who has placed a high value on the interdisciplinary connections, particularly with biology, and how housing market data and water quality data have merged together to support her research with her students. “It’s just so exciting to see it happen, a great opportunity for the students as well.” 

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Spring lessons: On the water, where geology meets civil and integrative engineering 

It’s a blazing hot late spring day on the Bushkill Creek at Lafayette’s dam, an appropriate backdrop for the kind of get-dirty-and-gritty learning environment that makes Lafayette classes and labs come alive.

Removing a machete from his pack of gear, a khaki and camouflage-clad Dru Germanoski, Dr. Ervin R. Van Artsdalen Professor of Geology, takes several hearty whacks at Japanese knotweed, a thick, reedy invasive plant that chokes the stream banks. He clears enough of it to make room for the geology and engineering students to move around safely and place their equipment.

Out on the creek, above the dam, David Brandes, professor of civil and environmental engineering and Walter A. Scott Chair of Integrative Engineering, is in a kayak helping his students position and secure a line to an eyebolt, allowing consistent surveying over time of cross sections of the creek both above and below the dam. 

As excited as a first-year student on his first field experience, Germanoski, with his students, is gathering data on how the streambed and hydraulics will change with the removal of the dam as sediment disperses with the creek’s elevation shifts. 

“That sediment will start to get eroded because the energy of flow is proportional to the slope,” he says. “And that’ll cause sediment to erode upstream of the dam. What will eventually happen is this stream will create its own sort of natural gradient, or slope, here that will basically be a new equilibrium.”

Germanoski also observes the pools in the less active water above the dam and how they warm up in the summer, affecting the migration of trout trapped in that area. 

“Whereas, every time you’re taking a dam out, you’re opening up passage for the fish,” he says. “So that movement is really important to the fish. This allows temperature-stressed fish in warmer pools to move freely to find cold water discharging from springs during the heat of summer. During spawning season fish can migrate into the Bushkill Creek from the Delaware River to spawn. This not only helps the Bushkill, but it helps the fisheries in the Delaware River as well.”

People often associate dams with flood control or flow management; however, these Bushkill dams play no positive role in flood control, Germanoski further notes.  

“They are not flood control dams and were not constructed to provide any flood protection. They have very little water storage capacity and do not provide any real measure of flood control,” he says. “In fact, dam removal will reduce local flood impacts. As the channel downcuts through the legacy sediment stored above each dam, it will increase channel capacity, which means the channel can convey more water within the channel without flooding.”  

Navigating his kayak to shore, Brandes takes a philosophical view of all the interdisciplinary work that’s been done by Lafayette over the years.

“Part of it is environmental stewardship and giving something back to the larger community. The Bushkill Creek is our neighbor, our natural boundary between campus and the city of Easton,” he says. “I think it’s fair to say, it was essentially ignored by almost everybody until the Karl Stirner Arts Trail was established in 2011, soon after we started conversations about dam removal on the lower Bushkill.” 

Access to the stream from the trail has brought to light its potential as a recreational green space, and so removal of these dams will continue the work of connecting people to nature in a mostly urban environment, Brandes says, adding, “that’s what makes this project so important.” 

“Our hope is that the project will encourage others to invest more in the stream as an asset to our community, rather than letting it remain a forgotten industrial corridor,” he says. “I have had several teams of students, in engineering courses and environmental studies capstone, and also tech clinic, contribute fabulous ideas to what this place could look like. Imagine sitting on a deck above the former dam site and enjoying lunch and a cold beverage while listening to the sound of water running over the rocks!

“Many people who work at Lafayette don’t even know there’s been a dam here,” he notes. “It’s an opportunity to restore this section of stream back to a natural state, so that it will support not only trout but also migratory American shad, eels, and, of course, mussels. 

“And the fact that it’s so close to campus just makes it an incredibly great opportunity for students to get involved in meaningful multidisciplinary research. This is the kind of project where collaboration and commitment of many partners with differing expertise are needed,” Brandes says. “The long process it took us to finally get to the point of dam removal is a great example of the perseverance that is often necessary to effect environmental change.”

Nearby, Liam Thompson ’24 (integrative engineering), in a wetsuit helping guide the line, is interacting with geology students, appreciating the symmetry of a familial discipline and finding shared areas of expertise. 

“It’s cool because they have a similar background,” he says. “They work with a lot of the same stuff that we use to build. We’re all kind of doing the same thing, right? They’re doing geology and we’re doing engineering, and we share a common language. It all fits.”

Thompson works alongside Elise Walsh ’25 (geology), Eve Bertoni ’25 (civil engineering), and Taylor Wininger-Sieve ’26 (geology). 

“It’s fun being in the water. I can see myself doing a job like this after Lafayette,” Walsh says. “Lots of problem-solving and collaboration with engineering.” Bertoni, positioning surveying equipment, agrees: “Outside and hands on, what could be better?”

Germanoski is grateful for the opportunity to work alongside Brandes and Rothenberger for so many years on the Bushkill project, sharing a common interest in helping restore the creek. He’s equally grateful for the real-life learning opportunities that have opened up for so many students.

“Everything is so multidisciplinary and multifaceted that it’s just necessary we think across the boundaries and think about how  projects like these benefit students,” he says. “They learned that even though they each have a little bit of a different expertise, they overlap and they come together and enhance one another. They discover that the whole is more than the sum of the parts. It’s really beautiful. This is actually training them for what’s coming next.”

It’s also been about bringing back the health and natural beauty of the Bushkill Creek and the restorative benefits to the human soul. 

“The human element is so crucial,” Germanoski says. “The benefits that people derive from a stream, psychologically and emotionally, to be able to come down here and just sit or to fish, it does wonders. It’s just so peaceful and cool along the Bushkill, a place to nourish our emotional health.”