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Massachusetts Water Resources Authority
March 19, 2007
CONTACT: Ria Convery, Communications Director
(617) 788-1105, <>


Report Highlights Progress Made During 2006


aerial of bay


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

> MWRA Presentation: CSO Progress Update - PDF (March, 2007)

On March 15, 2007, the Massachusetts Water Resources Authority submitted its 2006 Annual Progress Report (PDF) on the Combined Sewer Overflow (CSO) Control Program to the federal court. 

The report is required under Schedule Seven of the federal court Order in the Boston Harbor Clean-up Case and highlights the progress and accomplishments of CSO Control design and construction during 2006.

A major achievement of 2006 was Federal District Court Judge Richard G. Stearns’ April 27 approval of a long-term CSO Control plan for Boston Harbor and its tributaries. In his comments, Federal District Court Judge Richard G. Stearns described the clean up of Boston Harbor “one of the most successful modern public works projects ever undertaken.”

The goal of the CSO Control Plan is to protect swimming beaches, shellfish beds and other sensitive waters from overflows due to heavy rains. The plan strikes a balance between increased environmental cleanup and responsible levels of spending. It includes projects specific to Boston Harbor, the Charles River, the Alewife and Mystic Rivers, and to East Boston and North Dorchester. It also includes five, three-year variances, and a three-year assessment at the end of construction.

To date, 16 of the 35 CSO control projects identified in the 15-year plan have been completed.  Some of the highlights for 2006 include:

  • MWRA completed the $3.2 million construction contract for Pleasure Bay Storm Drain Improvements in March 2006, in compliance with Schedule Seven. The work has eliminated storm water discharges to Pleasure Bay beach, making Pleasure Bay one of the cleanest urban beaches in the nation.
  • In July 2006, MWRA awarded the construction contract for the $145.7 million North Dorchester Bay Storage Tunnel, in compliance with the court schedule. This project will virtually eliminate CSO discharges to the South Boston beaches. The tunnel contract is the single largest contract within the plan for North Dorchester Bay and in MWRA's entire long-term CSO Control Plan.
  • Boston Water and Sewer Commission (BWSC) completed construction of the MWRA-funded $45 million Stony Brook Sewer Separation project in September 2006, reducing the number of annual CSO discharges to the Stony Brook Conduit (which discharges to the Charles River Basin) from 22 to 2. The project has also reduced the volume of discharges from 44.5 million gallons per year to 0.13 million gallons per year.
  • MWRA continued to make progress with the $11.0 million construction contract for the BOSO19 CSO Storage Conduit, and the work is more than 90% complete. The storage conduit will reduce the frequency of annual discharges to the Little Mystic Channel in Charlestown from 13 to 2 and reduce the volume from 4.4 million gallons per year to 0.6 million gallons. MWRA expects to complete construction by March 2007.

The report includes details on these important projects and many others.

By 2015, MWRA is projected to spend over $850 million on CSO control projects, in addition to the $3.8 billion already spent on the Boston Harbor Clean-up which has dramatically improved the health of the harbor and brought people back to Boston’s waterfront.

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