What They Learned: Ceci Silberstein ’19

The first Haverford student ever to graduate with a major from the recently founded Bi-College Department of Environmental Studies used techniques she learned as a double major in mathematics to study stream health in Philadelphia.

Ceci Silberstein ’19 is the first Haverford student to graduate with a major from the newly-minted Bi-College Department of Environmental Studies. The department, which previously only offered a minor, was able to expand to a major after years of work from faculty, administration, and students. (Search committee representatives Kaitlin Reese ’20 and Ashley Boyette BMC ’20 were instrumental in bringing this major to life.)

As if being the first Haverford major weren’t enough, Silberstein also majored in mathematics at Bryn Mawr and wrote a joint mathematics-environmental studies thesis by using statistical tools to study the biological health of streams.

Silberstein was guided in this singular undertaking by Bryn Mawr Mathematics Professor Victor Donnay, who also carries an affiliation with the environmental studies department. As a liaison between the two departments in which Silberstein studied, Donnay was able to help her identify a project that simultaneously satisfied the requirements of both departments’ thesis projects by partnering Silberstein with the Philadelphia Water Department.

Professor Donnay has formed many partnerships with organizations around the city for praxis courses at Bryn Mawr—courses that teach applied math in the context of real-world projects,” she said. “My project with the Philadelphia Water Department stemmed from one of these partnerships. Professor Donnay also helped me balance the Water Department’s interest with the expectations for a ‘math thesis’ at Bryn Mawr—your typical water-resource management paper wouldn’t include a mathematical proof!”

Specifically, Silberstein studied how statistical methods can be used to track the effectiveness of tools that measure the holistic healthfulness of a waterway.

“My project was a small piece in an ongoing effort by the Philadelphia Water Department to test the efficacy of an existing stream health monitoring strategy on Philadelphia streams,” said Silberstein. “We learned that there’s a way to go as far as collecting and organizing relevant data before it is possible to fully implement this tool.”

Part of this difficulty comes from the environments in which these waterways exist: as portions of an urban ecosystem, these streams are susceptible to all sorts of biological factors. Because of this, Silberstein’s work hinged on being able to conglomerate measurements of these factors into one workable mathematical structure.

“We were able to take the existing data on different characteristics describing the ‘urbanness’ of a watershed and synthesize them into a single gradient,” she said. “We also used GIS [geographic information system] software to plug the existing data into the U.S. Geological Survey’s more wide-reaching Stream Stats database to collect data on additional watershed characteristics and develop an ‘alternate urbanness’ gradient.”

Ultimately, Silberstein’s work set the stage for future iterations of this project. By honing the statistical tools used for the study, she has primed the Water Department to expand the project’s scope and effectiveness.

“The next step for the water department is pairing these gradients with biological data,” she said. “This will be a challenge because that data needs to be consolidated, cleaned up, and then processed into a gradient, but it was encouraging to see that learning a little bit of technology can enable a wide array of data for hundreds of sites to be synthesized into a useful tool.”

What did you learn from working on your thesis?

I got the chance to learn about ecology, statistics, and resource management from the perspective of water managers. Our partners at the Water Department sent over some of the existing literature on the statistical tool they are developing, and from there we explored some of the underlying math and history. It was interesting to see how the same biological health indicators that you can look at pretty much anywhere in the country need to be scaled differently to differentiate sites in highly urban areas. It was also interesting to see that landscape “urbanness” in the context of the biological health of streams can be boiled down to the same widely available characteristics in many urban areas. This gives hope for future information sharing and resource sharing among urban water departments across the country!

What are your plans for the future and did your thesis have anything to do with helping to guide your future career path?

I will be working for the Pennsylvania Horticultural Society through the Haverford House fellowship. The Philadelphia Water Department has a growing program to address stormwater management through strategic greenspace. Many of the Pennsylvania Horticultural Society’s gardens support their irrigation with rainwater. There are lots of little overlaps in the organizations’ goals, resources, and bureaucracies and I am looking forward to exploring the same issues of organism health, water management, and public health from different angles in the coming year. My thesis dealt with synthesizing different numerical ways of describing one taxanomic group’s health, but there are lots of different ways of talking about health, and there are lots of ways organisms are deeply intertwined across an ecosystem, so I will be taking these quantitative skills with me and learning about new layers and techniques as I learn more about Philadelphia’s particular ecological, infrastructural, and public health challenges and hone in on my own interests and niche.

“What They Learned” is a blog series exploring the thesis work of recent graduates.