and Massachusetts Bay
MWRA developed a Contingency Plan to
ensure that discharge from the Bay outfall does not result in adverse impacts.
The Plan identifies thresholds that can suggest that effluent quality
or conditions in the Bay may be changing. When monitoring indicates that
"Caution" or "Warning" threshold levels for certain environmental indicators are
exceeded, these exceedance reports must be posted
on this website.
Contingency Plan Reports:
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 the
Plan Quarterly Report on Effluent Monitoring
Summary of data on pH, fecal coliform, toxicity, oil and grease, and nitrogen
in Deer Island Treatment Plant effluent (treated wastewater) compared
with threshold limits in the Contingency Plan.
The annual outfall monitoring overview presents monitoring program results for
effluent and field data from the previous year. All results are compared to Contingency Plan thresholds.
Proposed Modifications to the
Contingency Plan (November 2001)
Proposed Contingency Plan threshold modifications to dissolved oxygen
concentration, dissolved oxygen saturation, and Alexandrium abundance.
(See previous modification request)
Outfall Contingency Simulation: Treatment
Plant Chlorination Upset and Red Tide
Simulates the notification and decision-making processes that would occur
in the event of unexpected problems at the treatment facility or in Massachusetts
Questions? Email the Environmental Quality Department