Friends of Casco Bay has been collecting data on the environmental health of Casco Bay for over 25 years. Volunteers have been a vital part of our work through our Citizen Stewards Program. Below we discuss the details of the Citizen Stewards Program that started in 1992 and continued through the 2017 sampling season. You can read more about the history of our entire Water Quality Monitoring Program or our current science work.
Our Water Quality Monitoring initially was designed to address: How healthy is the Bay? Where are the problem areas?
Spatial, episodic monitoring by volunteers provided a “snapshot” of the environmental health of the Bay. Volunteers measured dissolved oxygen, temperature, salinity, water clarity, and pH (the level of acidity of the water).
Volunteer Citizen Stewards sampled surface waters from shore from April through October
The data were collected by volunteer citizen scientists, whom we trained to rigorous specifications (using a Quality Assurance Project Plan). These stewards used Secchi disks and water quality test kits specifically designed by us as “Casco Bay kits” with the help of LaMotte Company.
After pulling up buckets of seawater at their shoreside sites, volunteers carefully mixed chemicals, titrated, and flocculated, to get measurements for dissolved oxygen, salinity, pH, temperature, and water clarity. They would devote more than an hour at a time to monitor their assigned stations, at appointed times in both the morning and afternoon, on ten Saturdays from April through October.
Their data enabled us to identify when and where we were most likely to find water quality variations throughout the sampling season. These data, along with other staff collected data, helped us address our early questions, “How healthy is the Bay?” and “Where are the most challenged regions of the Bay?”
These data have:
- Provided critically important baseline data; we continue to build on this data set at key sites around the Bay
- Buttressed our advocacy and community outreach to tighten environmental protections for Casco Bay
- Enabled us to create an annual Health Index of the Bay using Citizen Stewards data
- Identified areas where further study is needed
- Showed that the water quality of certain areas of the Bay have consistently remained healthy or challenged:
- Portland Harbor, the New Meadows embayment, and Harraseeket River mouth showed the poorest water quality
How the data have been used
Because the program follows an EPA-approved quality assurance plan and the data is scientifically sound, it is sought-after by other researchers, state officials, and policy makers. For example, our oxygen data has been used to determine the Clean Water Act “grade” that the State assigns to a water body and the amount of pollution that is allowed to be dumped into the state’s coastal waters. Our data convinced the State Legislature to upgrade the water body classifications for parts of Portland Harbor from the lowest grade, SC, to a healthier SB. Our data also helped to increase protection for The Basin, a popular anchorage in Phippsburg, raising its classification from SB to SA, the highest level of water quality protection.
Once an area has been upgraded, state law prohibits anyone from discharging pollutants that would degrade the water quality of that water body. What does that mean for those who swim, fish, and play in the Bay? A pledge to limit pollution from sewage treatment plants, industrial facilities, and other dischargers.
The data collected by our citizen scientists helps provide an appraisal of the overall health of the Bay, summarized in the Casco Bay Health Index. We created the Casco Bay Health Index as a reliable, easy to visualize overview of the health of the Bay that enables us to identify where problems exist. The Health Index allows us to rank the water quality of each site we sample as Good, Fair, or Poor. In problem areas, low oxygen levels, murky water that prevents sunlight from penetrating deep into the water, and rising acidity levels are recipes for troubled waters. We may not be able to identify the causes of these changes, but our monitoring efforts do show where problems lurk.
Why sample twice a day?
Citizen Stewards sampled at 7 a.m. and again at 3 p.m. Sampling twice a day throughout spring, summer, and fall provides a unique opportunity to assess daily fluctuations. Water quality typically changes from a “worst case” to a “best case” scenario as the day progresses. Knowing that helps us better understand the rhythm of the Bay. The water quality tends to be lower in the morning and higher in the afternoon as oxygen levels in the water increase, pH rises.
Throughout the day, microscopic plants called phytoplankton absorb sunlight and photosynthesize, releasing oxygen into the water. At night, the process is reversed; phytoplankton absorb oxygen from the water. Our data shows that water chemistry is clearly impacted by this cycle of photosynthesis and respiration, and the decomposition of phytoplankton.
Some areas of the Bay experience dramatic daily swings in oxygen, and pH. Often these regions, such as narrow embayments in eastern Casco Bay, are where we find substantial crops of phytoplankton thriving in the water column. When these phytoplankton die and decay, the bacteria that break them down consume oxygen from the water, which other marine life needs. At times, the oxygen levels may get so low that it stresses marine organisms and has even led to fish kills.
Decomposition of these marine plants can also release more carbon dioxide, raising the acidity of the sea water. This makes it harder for baby clams and other shellfish to build their protective shells.
Cover photo: Photograph by Kevin Morris
Thank you to all of our Citizen Steward Water Quality Monitoring Program Volunteers!
We’ve had so many wonderful and dedicated Citizen Stewards over the years. If you were ever a Citizen Steward Water Quality Monitoring Program Volunteer with us and you are not listed below, we apologize and ask that you please let us know by calling the office at (207) 799-8574 or emailing keeper [at] cascobay [dot] org.
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