MWRA's Boston Harbor Page

Boston Harbor and Massachusetts Bay
MWRA Environmental Quality Department

Boston Harbor and the Tributary Rivers


Boston Harbor	Beaches	Charles River	Mystic River	Neponset River

INNER HARBOR SURFACE TEMPERATURE RANGE: 53-61° F

ABOUT BOSTON HARBOR

Boston Harbor encompasses nearly 50 square miles and is an estuary, where fresh water from tributary rivers mix with the salt water of Massachusetts Bay.

The Massachusetts Water Resources Authority monitors water quality at more than 50 locations in Boston Harbor. Measurements are also made in the Charles, Mystic, and Neponset rivers. The monitoring program is designed to monitor the impacts of combined sewer overflows (CSOs) on the Harbor and rivers.

See larger map with sampling locations

Water Quality Parameter		Historic Range for Boston Harbor*	Data
	Dissolved Oxygen	1.29 - 14.31 mg/L Mean: 7.54 (7886 readings)	Download physical data
	Temperature	46.2 - 74.9 deg F Mean: 60.9 (7978 readings)
	Salinity	0.29 - 33.73 PSU Mean: 29.75 (7800 readings)
	pH	6.47 - 9.95 Mean: 7.82 (6922 readings)
	Secchi Disk Depth	0.2 - 6.9 m Mean: 2.39 (3300 measurements)	Download clarity data
	TSS	0.37 - 20.2 mg/L Mean: 3.85 (1981 samples)	Download clarity data
	Nutrient Chemistry	DIN: 0.03 - 27.5 umol/L Mean: 3.15(783 samples)	Download nutrient data
	Chlorophyll & Phaeophytin	Chl a: 0.53 - 18.4 umol/L Mean: 3.75 (1994 samples)	Download nutrient data
	Enterococcus	0 - 169000 count/100 mL Geo. mean: 2 (4531 samples)	Download bacteria data
	E. coli	0 - 261000 count/100 mL Geo. mean: 3(2372 samples)
	Fecal coliform	0 - 968000 count/100 mL Geo. mean: 7(2706 samples)

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