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Massachusetts Bay


Photograph of data collection buoy in Massachusetts Bay
Instruments attached to a buoy near the Mass. Bay outfall (shown) provide MWRA with continuous water quality information.
(Photo: National Data Buoy Center)


MORE INFORMATION
Mass. Bay bacteria data
Outfall Monitoring Overview
UMass Dartmouth Bay modeling
Useful Links
Literature List
Outfall Papers (abstracts)

Now that the Boston Harbor Project has ended, there is little doubt that the upgraded sewage treatment system has benefited the marine environment.

BAY WATER QUALITY
Buoy collecting hourly data off Cape Ann Link to instrument location near Stellwagen Bank Link to Outfall instrument location
Bay water quality is measured using buoys at two locations (click to see data):
Cape Ann locationOff Cape Ann near Stellwagen Bank, and

Outfall location Near the MWRA outfall.

Compare the two stations last five days (courtesy: Univ. of Maine)

A major part of the project: to stop discharging treated wastewater (effluent) into Boston Harbor. Instead, an underground outfall tunnel carries effluent from MWRA communities out into Massachusetts Bay.

MONITORING DATA
The annual Outfall Monitoring Overview contains monitoring data from Massachusetts Bay. Over the years, monitoring has revealed that:
•
The quality of the effluent (treated wastewater) has improved, due to better control of pollution sources.
• Chlorophyll, plankton, and dissolved oxygen levels are normal.
• Concentrations of contaminants in sediment samples near the outfall are low and do not vary much. Pictures of sediments near the outfall show healthy, normal communities.

When MWRA began discharging into the Bay, a water quality monitoring program was implemented to assess any effects of treated sewage on the Bay. The Ambient Monitoring Program has enabled MWRA to better understand the natural variability in the Bay's water quality. Monitoring has shown that the water near the outfall and throughout the bays is heavily influence by river inflows, weather, and other factors.

Data continue to confirm that there are some detectable effects of the discharge near the outfall, such as increased ammonium. However, there are no detectable adverse effects at stations away from the outfall. Dissolved oxygen levels in bottom waters near the outfall have not changed and remain within state water quality guidelines.

MWRA's goals for Boston Harbor and Massachusetts Bay are based on concerns expressed by the public during the planning of the Boston Harbor Project. These goals include clean beaches, healthy marine resources, seafood safe for eating, and protection of the natural beauty of the harbor and the bay.