Emma Zeitler, C'20, conducts research in Sewanee's constructed wetland. Photo by Buck Butler

Discerning the Shape of Water

Students and professors in a variety of disciplines take advantage of Sewanee’s local ecology to engage in water and water-systems research that is as deep as it is wide.

When rain falls in Sewanee, it is either taken up by organisms, evaporates, or makes its way to the Tennessee River by a more or less circuitous path. To the south and east, runoff heads down Crow Creek or Battle Creek, pretty directly to the Tennessee, though it will also percolate into the rocks and take its sweet time through Buggy Top Cave and other crevices. To the north and west, the route is more circuitous, down Boiling Fork Creek or Dick Creek or Mud Creek, which flows out of Shakerag Hollow, and into the Elk River, which then meanders across southern Middle Tennessee and North Alabama, cutting through Pea Ridge before it meets the Tennessee about 15 miles upriver from Muscle Shoals.

What happens to that water between the gathering of the clouds and the flowing of the creeks is a matter of great interest to a growing group of researchers at Sewanee. Some of it collects in ephemeral ponds, jacking up local biodiversity before evaporating or percolating down through the rocks. A good bit more passes through the machinery of the Sewanee Utility District and the thousands of citizens it serves, picking up coliform bacteria or pharmaceuticals or microplastics from laundry and toothpaste along the way. In a heavy rain event, streams flush through neighborhoods, carrying silt and plastics and other detritus to low-lying areas and stressing the populations of aquatic species.

“The important thing to remember is that we are at the top of the watershed,” says Ken Smith, assistant dean of environmental programs. “That means our drinking water is about as clean as you can get, and also that we can measure what we do to that water at the municipal scale and get insights that researchers in other areas cannot. What happens here matters here, but it also matters elsewhere. We are starting to understand that better every day.”

Several years ago, Smith, along with colleagues Karen Kuers and Martin Knoll, put together a watershed science certificate, which now also involves Assistant Professor Keri Watson, and Biehl Professor in Biology Deborah McGrath. Along with Amy Turner, director of the Office of Environmental Stewardship and Sustainability, Rob Bachman in chemistry, and several colleagues in biology, Sewanee professors and their students are exploiting the local ecology to produce an ever more robust understanding of the fate of water.

Now that group is beginning to build coherence and traction, as exemplified by what Smith has called the Year of Water. One night in late February, some of these researchers gathered in Gailor Hall for a panel discussion of their work: a lightning round of presentations followed by scripted questions generated by Smith and asked by students. The room was full for what was the eighth event sponsored by Sewanee’s Integrated Program in the Environment called “Water is the Best Thing,” or, in the original Greek, APIΣΤΟΝ ΜΕΝ ϒΔΩΡ. Over the course of the year, Sewanee audiences had heard from researchers, authors, historians, filmmakers (and films) that teased out the complex relationships between aquatic ecosystems and the human beings who depend on them.

Emma Zeitler, C’20, introduced the panel. A sophomore, Zeitler came to Sewanee knowing exactly what she wanted to do—research in ecology. “Dr. McGrath pulled me in to work on the constructed wetland,” she says, “And then I was able to start working with Dr. Cecala on amphibian research.” The constructed wetland is a relatively new research station made possible by grants from the Coca-Cola Company and Coca-Cola Bottling UNITED, with a grant from the Riverview Foundation supporting Sewanee’s partnership with the University of Georgia. It was envisioned as a way to learn if a wetland has the ability to clean water at a small utility to standards higher than currently mandated by the Environmental Protection Agency, particularly in cleaning up pharmaceuticals in the water. Zeitler has been working to answer a simple question: Will amphibians thrive in the constructed wetland compared to their cousins in native environments? Yes, is the short answer.

Now she and Assistant Professor of Biology Kristen Cecala are adding a layer to the research. They have released 3,000 tadpoles in 24 mesocosms, basically cattle tanks near the wetland filled with water from three different sources: Lake O’Donnell (Sewanee’s primary drinking water source), a wastewater lagoon, and the constructed wetland. This semester, the two researchers have worked hard to set up the experiment, filling the tanks and helping create a somewhat natural environment. “One of Dr. Cecala’s colleagues recommended we put leaf litter in each tank, so I gathered a lot,” says Zeitler. “Enough to put a kilogram of leaf litter in each of the mesocosms.” Zeitler has just been awarded a Ledford Scholarship from the Appalachian College Association for her work on the project this summer.

On the panel, Cecala summarizes her multifaceted research on dynamics of amphibian populations in the Southeast. Deborah McGrath, co-director of the wetland project, followed, discussing how this experiment station is helping researchers investigate more and more questions. Keri Watson, C’12, discussed her research on ecosystem services and stormwater effects and how that might find application in Sewanee. That night, Watson was, in fact, in her second month as a professor at Sewanee, having just completed a Ph.D. from the University of Vermont. Martin Knoll, C’82, reprised a discussion of Tenneswim. Ben Beavers, director of the Sewanee Utility District, explained how research keeps the District able to supply the community clean, safe drinking water, and Eric Keen, C’08, a visiting professor in environmental studies, talked about his research on marine mammals.

After the presentations, the panel sat for questions, first from student moderator Kailey Bissell, C’18, and then from the audience. Bissell is herself among the researchers doing water-related work, early in her career with Cecala and now with Assistant Professor Katherine McGhee on the responses of fish species to predation risk. “The biggest water-related issue in our Sewanee community is related to a clean, safe water supply,” said Watson, in answer to Bissell’s first question. “Part of what I study is storm events, but I also think it is important to think about water scarcity, and the two things are related. With climate change, we are likely to see more extreme events, both flooding and drought, and that makes it difficult for a community like Sewanee to ensure a clean, safe water supply.”

For Deborah McGrath, the most important issue has to do with environmental justice. “The work that we have been doing with the constructed wetland is really important,” she says. “And one reason it is important is that we are lucky to be at the top of the Mountain, essentially drinking rainwater. But the people downstream from us—which is basically everyone from here to New Orleans—get our waste. So what we do to make sure our wastewater is as clean as possible is really important from the point of view of environmental justice.”

As for a problem with more global dimensions, Martin Knoll focused on microplastics. “So, in Tenneswim, we collected microplastics [tiny pieces of plastic that have broken down from larger pieces and that are invisible in the water],” he tells the audience. “And there was so much, we had to change the filters more often than we had planned. One of the goals of Tenneswim was to compare the Tennessee to the Rhine, because our swimmer/researcher, Andreas Fath, had completed a swim of both streams. Even though the Rhine Valley is the home of many more people than the Tennessee Valley, microplastics were much more prevalent here. We found there are about 8,000 microplastic particles per cubic meter of water in the Tennessee River, compared to only 200 for the Rhine. That’s a problem. Microplastics can form a matrix and can attract harmful chemicals, pathogens, and all of that enters organisms like fish and people.”

Ken Smith and Amy Turner have recently worked on a successful grant proposal to the Arthur Vining Davis Foundations that will continue to build coherence among student and faculty researchers doing water-related work. An important focus of the project, called the Sewanee Headwaters Initiative, is to connect research more clearly to conditions the public faces. The grant will allow Sewanee to hire a research manager who will also help faculty develop a public-facing dissemination strategy for water-related research. For Turner, “This project represents a powerful connection between an office with staff dedicated to managing the Domain and faculty who are interested in the research and teaching that takes place on it.”

One of the pioneers for water research on the Domain was Karen Kuers, the Annie Snowden Professor of Forestry, who was principal investigator on a previous grant that established a watershed research site. In fact, this may be a kind of origin story for the Sewanee Headwaters Initiative. Beginning in 2001, Kuers became part of a regional network of scientists who began collecting data on the interactions between weather and Appalachian forests. Kuers’s work, and that of her colleagues at colleges across the region, is what is known as a longitudinal study. “The project began with my participation in a multi-college research project entitled ‘Collaboration Through Appalachian Watershed Studies,’” she explains. “The purpose of the project was to facilitate collaborative environmental research and teaching among small undergraduate institutions.” The colleges range from Middle Tennessee State University to the University of Maryland, and provide opportunities for students to compare watershed processes across the Appalachian region and share their work online.

Kuers and her students installed a weir and a weather station in the Split Creek watershed, near the Forestry Cabin. The weather station records precipitation, and the weir records runoff—all within about 50 acres. Researchers also look at other metrics, gathering leaf litter as a proxy for forest production, photographs of the forest canopy to measure the leaf area index. Early on, the Split Creek researchers placed laundry baskets at regular intervals throughout the research site to gather leaf litter, using statistical analysis to measure total forest production and carbon sequestration. In the past three years, Kuers has had to adapt to an influx of armadillos, which upend the baskets, looking for food. The solution? Window screen suspended from a hoop of PVC held off the ground by metal fence posts.

Kuers’s data is not only available to colleagues across the region, she is now making it available to her new colleague, Keri Watson, who is working with students this semester on the beginning of a long-term project to assess how development of the Sewanee Village might have environmental impacts downstream. Watson and her students, Glenn Ireland, C’18, and Charlie Williamson, C’18, are installing instrumentation to measure runoff from the Depot Branch watershed, the small creek that drains the area around the Village. “We had trouble getting going,” she says. “The first time, we installed flow meters at the confluence of two culverts, and after a storm, there was so much water that it overwhelmed the ability of the stream to drain. Now we are hoping for another storm event so we can measure in a new place.”

Watson takes out a pencil and draws an illustration of a stream channel to demonstrate how measurements are taken. It’s a laborious technique, involving taking stream depth measurements at regular intervals to get an idea of volume. “This is a good technique to know how to do, but it would also be great to have a weir for the Depot Creek watershed to match the Split Creek unit. Then we could continuously record data rather than having to develop a stream profile each time we take a measurement.”

Watson is excited about the possibility of having a paired research station. “In terms of size and shape, the Depot Branch watershed is much smaller than Split Creek, but what a paired system can show us is the difference between runoff in an undisturbed location and a disturbed location.” For Watson, getting this data about what happens after disturbance is key to doing scenario planning, which allows people who are considering development to understand what that development will do to human and animal neighbors downstream. Watson works in what is known as ecosystem services, which tries to assign value to nature—a task that involves the kind of data sets that Kuers has been collecting.

In the words of Ken Smith, the grant from the Arthur Vining Davis Foundations is “a game changer.” It could fund at least partially the Depot Branch weir and inform the process of downtown development. It will help extend research at the constructed wetland. It will help Martin Knoll drive insights from Tenneswim more fully into public consciousness. It will help researchers in biology, forestry, and earth and environmental systems start to quantify the effects of climate change on people and animals.

“We think that building a kind of structure within which we all can continue to talk with each other and support each other in our research and teaching comes at exactly the right time for us,” he says. “The Year of Water may be over, but we are now beginning some really fruitful and collaborative work to connect our research to public needs and the public good. This is part of our ongoing effort to make Sewanee’s environmental program the best of any liberal arts university in the nation.”