Students Present Pleasant Lake Research Project to College, Community

Soft laughter fills the room as the presentation screen flashes pictures of students standing knee-deep in road culverts. The photos portray students wearing wader boots, headlamps and smiles.

“So next time you see college kids playing in the waters around Pleasant Lake, know that we might be conducting serious environmental work,” says junior Steven Williamson. “And while it may look like a lot of fun, I can assure you, it is.”

On Tuesday April 23, Colby-Sawyer juniors and seniors majoring in environmental science and environmental studies presented their community-based project to the college and community.

“The community-based project is an awesome opportunity for our environmental science and studies students to apply the knowledge and skills they have learned in their courses to a community environmental issue,” Professor Nicholas Baer said. “The students work as consultants throughout the fall and spring semester to collect, analyze and communicate their findings and possible solutions to an outside partner organization. Throughout the year, students enhance their technical skills as well as project management, science communication and team dynamic skills.”

This year, the group of 10 worked with the Pleasant Lake Protective Association (PLPA) to better understand the Pleasant Lake watershed and surrounding tributaries. The watershed is the area around Pleasant Lake that channels rainfall, snowmelt and runoff water into the lake. The primary goal of the project was to find potential causes for the cyanobacteria blooms that have appeared in Pleasant Lake the past two summers.

To gather their data, the group had to collect water samples from the lake throughout the fall and spring semesters and run the samples for specific parameters. In total they sampled 22 days and collected 750 water samples.

Phosphorus was one of the main parameters that was examined, since too much phosphorus in the lake can lead to cyanobacteria blooms.

“Beyond just testing total phosphorus in the lab, we wanted to understand what factors would lead to areas with higher concentrations and daily loading,” junior Samantha Carus said. “We worked with satellite imagery to understand land use in the watershed and looked at town septic records to understand how human development could impact the watershed.”

The results showed a significant, but weak, relationship between development in some tributaries and their phosphorus concentrations, specifically areas covered by more houses and paved surfaces. They also found several tributary sites to continuously monitor, as they could be future sites for cyanobacteria blooms due to their substantial contribution of phosphorus into the lake.

Water samples collected from Pleasant Lake were also tested for chloride.

“Chloride is a pollutant of concern in terms of water quality, as rising concentrations can negatively impact freshwater ecosystems,” junior Quinn Aldrich said. “One focus of our study was to identify sites with consistently elevated chloride levels and determine the impact of salt application rates within each watershed.”

The study found that several state roads, such as Routes 11 and 114, are within the Pleasant Lake watershed and contribute 17 times more salt to the lake than the other town roads within the area. To combat the presence of chloride in the lake, the team suggested that the town of New London and the PLPA could work to develop a salt reduction program for state roads within the watershed and that Pleasant Lake residents could avoid salting their driveways to help reduce salt runoff in the lake.

Throughout this project, the class has gained significant data about the lake and the tributaries surrounding it. They plan on publishing a paper with the PLPA to summarize their findings and future steps.

“The Pleasant Lake Protective Association has provided additional funds for three of our students, Quinn Aldrich, Sam Carus and Steven Williamson to continue the research this summer in an effort to have a full year of in-depth water quality data for the lake tributaries,” Baer said. “[This project] was a tremendous effort, and my co-instructor, Dave Lutz, and I are very proud of the students’ work.”