Decades of Data: A Watershed Year for Science

This year we are marking two important milestones: our 30th season of monitoring the water quality of Casco Bay and the first full-year of having three Continuous Monitoring Stations in the water.

Staff Scientist Mike Doan says that both our Seasonal Sampling and Continuous Monitoring efforts are crucial to our mission to protect the health of the Bay. “Casco Bay covers more than 200 square miles of water,” he explains. “Our monitoring programs are designed to efficiently measure how healthy various parts of the Bay are while tracking how our waters are changing over time.”

“We are proud to say that we have stuck with science for the long-haul,” says Will Everitt, Executive Director of Friends of Casco Bay. “It takes tenacity to stick with any long-term project. It takes committed supporters and donors to ensure that we have the resources to continue this work year in and year out. If you are one of those supporters, thank you. You’ve helped us reach these milestones.”

The Casco Bay Estuary Partnership (CBEP), one of 28 federal National Estuary Programs, is among the many entities that put our data to use. “For three decades, Friends of Casco Bay’s monitoring efforts have provided a crucial part of the data used to understand the condition of Casco Bay,” says Curtis Bohlen, Director of CBEP. “The data are relied on by scientists and regulators alike. Friends’ thirty year history of monitoring the Bay provides a long term perspective crucial for understanding how the Bay is — and is not — changing.”

30 Years of Seasonal Sampling

Our Seasonal Sampling program continues to add to one of the most-important and long-term marine water quality data sets in New England. Data from this program helped to designate Casco Bay as a Federal No Discharge Area and upgrade Clean Water Act classifications for large areas of the Bay, ensuring our waters are better protected for years to come.

From May to October, Staff Scientist Mike Doan and Casco Baykeeper Ivy Frignoca take to our Baykeeper boat or truck and travel to 22 sites across the Bay.

“We are providing a health check-up for the Bay each day we are out there,” Mike explains. “Like a doctor checking your blood pressure, if we find an anomaly or problem, we can do more thorough investigations.”

365 Days of Continuous Data

Mike and Ivy use a scientific device that measures water quality characteristics called a data sonde to measure temperature, dissolved oxygen, pH, salinity, chlorophyll, turbidity, and water depth. They also collect water samples that we send to a laboratory to measure total nitrogen.

As of May 20, 2022, Friends has a full year of around-the-clock data from all three of our Continuous Monitoring Stations. In May 2021, we launched two new Continuous Monitoring Stations in Casco Bay, located off Harpswell to the east and in Portland Harbor to the west. These two Stations joined our original station off the coast of Yarmouth, near the coastal center of the Bay, first launched in 2016.

Mike designed our Continuous Monitoring Stations, which combine a data sonde with a sensor that collects carbon dioxide data. “We launched the stations to measure how the Bay is changing,” says Mike. “By looking at data collected every hour on the hour, we can better see through the noise of daily and seasonal changes, and understand how climate change may be impacting our waters. Having three stations up and running for more than a year now is giving us a clearer picture of what is happening in very different regions of the Bay.”

Our Continuous Monitoring Stations are maintained thanks to the generous support of the Casco Bay Estuary Partnership and the more than 700 Friends of the Bay who gave to our Climate Change and Casco Bay Fund.