Boston Harbor and Massachusetts Bay
MWRA Environmental Quality Department

Massachusetts Bay

Video of underwater life on an outfall diffuser Data collected hourly off Cape Ann provide MWRA with water quality information. (Photo: University of Maine) MORE INFORMATION Outfall Monitoring Overview Ambient Monitoring Program 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
	Water quality is measured at: Cape Ann near the outfall, and Stellwagen Bank. (click for live data)

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.

When MWRA began discharging into the Bay, a water quality monitoring program was implemented to assess any effects of treated sewage on the Bay. As part of this program, MWRA monitors bacterial water quality at monitoring locations near the sewage outfall and at more distant locations in Massachusetts Bay.

The Ambient Monitoring Program has enabled MWRA to better understand the natural variability in the Bay's water quality. MWRA has joined up with the Gulf of Maine Ocean Observing System (GoMOOS), who owns a buoy that monitors water quality upstream of the outfall, off Cape Ann. This water quality information allows MWRA to distinguish the impact of the outfall from other environmental factors.

To ensure that the bay monitoring is carried out in a scientifically defensible manner, an independent panel of scientists, The Outfall Monitoring Science Advisory Panel (OMSAP), reviews monitoring data and provides advice on scientific issues related to the discharge permit and related monitoring.

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.