Since 1992, more than 650 volunteers have gotten their hands wet in our Citizen Stewards Water Quality Monitoring Program, complementing the work of our staff scientists in assessing the environmental health of Casco Bay. This science is the foundation of much of our community engagement and advocacy efforts.
Volunteer Citizen Stewards measured dissolved oxygen, temperature, salinity, water clarity, and pH at nearly 40 shoreside sites on the same date and time on ten Saturdays from April through October, to create a simultaneous snapshot of surface conditions around the Bay.
Our staff scientists have monitored offshore at 10 stations, from surface to sea floor, aboard our research vessel, every month of the year.
The data allowed us to address these questions:
- How healthy is the Bay?
- Where are problem areas?
- What influences the health of the Bay?
What we have learned
- Casco Bay is generally healthy, compared with other estuaries.
- Year after year, our data has identified Portland Harbor, the New Meadows embayment, and the mouth of the Harraseeket River as the most environmentally challenged areas in Casco Bay.
- The healthiest regions of the Bay are Broad Sound, Maquoit and Middle bays, and the offshore waters near Halfway Rock.
- By sampling both along the shore and offshore, we determined that land-based origins contribute significant sources of excess nitrogen.
- The bottom water of the Bay has become more acidic, a worrying trend that mirrors what is happening worldwide.
- Summer is lasting longer beneath Casco Bay. Water temperatures are staying warmer into the fall.
- In order to better understand how the Bay is changing, we are increasing the frequency of data collection.