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Boston Harbor and Massachusetts Bay
Massachusetts Water Resources Authority

Ambient Monitoring

MWRA monitors water quality at the outfall location in Massachusetts Bay where treated sewage, or effluent, is discharged. This sampling program is termed Ambient Monitoring, because sampling is focused on the ambient, or surrounding waters at the outfall, as well as more distant locations. The program is detailed in the Ambient Monitoring Plan, which is monitored by state and federal regulators, as well as by the Outfall Monitoring Science Advisory Panel (OMSAP).

Monthly Bacteria Monitoring at the Outfall
Recent measure of sewage indicator bacteria, fecal coliform and Enterococcus, around the outfall and elsewhere in Massachusetts Bay.

Quarterly Ambient Monitoring Report
The results of all monitoring required by the ambient monitoring plan or the Bays Eutrophication Model must be reported quarterly to regulators, OMSAP, and the National Marine Fisheries Service.

Contingency Plan Quarterly Report on Ambient Monitoring
Data on mussel contamination, dissolved oxygen, and algae at sampling locations in Massachusetts Bay, compared with threshold limits in MWRA's Contingency Plan.

Older Reports

AMBIENT QUARTERLY MONITORING REPORTS
This Year
2014
2013
2012
2011
Quarter 4

Ambient monitoring plan for the Massachusetts Water Resources Authority effluent outfall revision 2. July 2010

Modifications to the Ambient Monitoring Plan, 2010

Bays Eutrophication Model (BEM): Modeling analysis for the period 2006-2007
MWRA must update, maintain, and run a three-dimensional water quality model called the "Bays Eutrophication Model" developed by Hydroqual and the United States Geological Survey. The model is designed to predict conditions caused by addition of nutrients to the bay, and is used to support decisions about nutrient limits in effluent discharges.

Ambient Monitoring Plan for the Massachusetts Water Resources Authority Effluent Outfall, Revision 1, March 2004

Special Study of Flounder Skin Lesions
In the April 2003 flounder survey, an increased number of flounder ulcers were recorded, with the highest prevalence in Western Massachusetts Bay. The condition was absent from Eastern Cape Cod Bay. The Outfall Monitoring Science Advisory Panel recommended further study of this condition. MWRA designed a study to further investigate the possible causes of these ulcers.

Outfall Maintenance and Diversion Plan (2000) 
This plan provides the protocol required to divert effluent flow in case MWRA is directed to temporarily shut down the exisiting outfall.

A review of issues related to the development of a food web model for important prey of endangered species in Massachusetts and Cape Cod Bays (2000)