monitoring water quality in Midcoast Maine estuaries

Maine Coastal Observing Alliance awarded grant for water monitoring

Tue, 11/28/2023 - 5:00pm

The Maine Coastal Observing Alliance (MCOA), a network of nine conservation groups monitoring water quality in Midcoast Maine estuaries, has received a grant for $142,000 from a fund at the Maine Community Foundation. The grant will be used to grow MCOA’s monitoring network and collect meaningful data for Maine’s coastal communities.

An estuary is a coastal water body where fresh water from rivers and streams mixes with salt water from the ocean. Maine’s estuaries support diverse marine life and thriving working waterfronts. But because they tend to be shallower and mix less with the open ocean, rain and runoff from land may put them at risk of increased acidity, reduced oxygen, and high nutrient levels. All of these factors pose a threat to the health and productivity of these waterways. 

Good data help communities understand the impacts of climate change and coastal acidification, and are essential to protecting water quality. MCOA was formed in 2014 in an effort to meet this need. The group collects estuarine water quality data using standardized equipment and protocols on an on-going basis, at a regional scale, from Belfast Bay to the Harraseeket River in Freeport. Without this regional approach, there is no way to know whether pollution is coming off the land or from the Gulf of Maine.

“This collaborative effort has been extraordinarily powerful,” said MCOA chair Sarah Gladu, in a news release. Gladu is also director of Education and Community Science at Coastal Rivers Conservation Trust. “Its regional scope allows us to compare data across estuaries, and now, as we approach a tenth year of monitoring, we have data that are meaningful across a significant span of time. MCOA also offers its partnering organizations tremendous capacity through meetings, calibration workshops, access to expert data analysis and shared data interpretation.”

MCOA partners include Boothbay Region Land Trust, Coastal Rivers Conservation Trust, Friends of Belfast Bay, Friends of Casco Bay, Friends of the Weskeag, Georges River Land Trust, Kennebec Estuary Land Trust, Midcoast Conservancy, and Rockport Conservation Commission.

Estuary monitoring takes place at five to eight sites in each of the nine coastal areas, twice a month for at least two months a year. Data are collected on transparency, dissolved oxygen, salinity, temperature, and total nitrogen. 

The Maine Community Foundation grant funding will help pay for staff time, consultant support, and new equipment, including nine data collection buoys that will be placed in each estuary for extended periods of time to collect continuous data.

“All of this will help communities understand what factors impact coastal acidification and enhance MCOA’s ability to provide high-quality, reliable data,” said the release.

For more information, visit MCOA’s website at or email Sarah Gladu at