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Massachusetts Water Resources Authority
For Immediate Release
September 12, 2007
CONTACT: Ria Convery, Communications Director
(617) 788-1105, <>



Today, the Massachusetts Water Resources Authority held a ceremony in South Boston “launching” the tunnel boring machine for the its combined sewer overflow (CSO) storage tunnel. This project is the single largest project in the $850 million CSO Control program. The goal of the MWRA’s CSO control program is to protect swimming beaches, shell fish beds and other sensitive waters from combined sewer overflows due to heavy rainfall.

Speakers at this morning’s event included Senator Jack Hart who welcomed the crowd to South Boston; Ian Bowles, Secretary of Energy and Environmental Affairs and the Chairman of MWRA’s Board of Directors; Robert W. Varney, EPA Regional Administrator; Boston Environment and Energy Chief Jim Hunt, who is also on the MWRA board; Boston City Councilor Michael Flaherty; environmental activists Bruce Berman of Save the Harbor/Save the Bay and Vivien Li of The Boston Harbor Association; and MWRA Executive Director Fred Laskey.  Federal District Court Judge Richard G. Stearns, who oversees the Boston Harbor Court Case, was also in attendance and said a few words about the project. Finally, Father Robert Casey, Pastor of Gate of Heaven and Saint Brigid, offered a blessing for the project.


Map of project with work description

project map


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Graph - Reductions in Overflows at South Boston Beaches

cso graph south boston


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MWRA 2006 CSO ANNUAL REPORT - PDF (Released 03/15/2007)

"This is a really important project to fulfill the promise of truly clean water in Boston Harbor," said Secretary Bowles.

According to Bob Varney, "This new overflow tunnel promises to significantly help our efforts to clean up Boston Harbor by dramatically reducing sewage overflows to our waters. The hard work of many people and organizations is going to pay off for Bostonians in the form of some of the cleanest urban beaches in the country.”

This 17-foot diameter, 2.1-mile long soft ground tunnel will eliminate combined sewer overflows and stormwater discharges to the beaches in South Boston.

For decades, combined sewer overflows have discharged about 21 times a year at six outfalls along South Boston beaches.  This project will eliminate CSOs to these beaches, except in a catastrophic storm event.  Stormwater drains also discharge to the South Boston beaches every time it rains - about 95 times a year.  The project will prevent stormwater discharges in up to a 5-year storm.

During wet weather, CSO and stormwater flows will be stored in the tunnel until the storm subsides.  The tunnel will then be pumped out and the flows sent to Deer Island for treatment and discharge.

After the project is constructed, beach closings will be a very rare occurrence - about once every 5 years.












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