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CSO Control in South Boston
Massachusetts Water Resources Authority

 

MORE INFORMATION
Trailing Gear

Inside the CSO Tunnel during mining: January 10, 2008

more photos

CSO Main Page

Boston Harbor Court Case

CSO ANNUAL REPORTS

MWRA 2007 CSO ANNUAL REPORT(Released 03/13/2008)

ABOUT THE PROJECT

The South Boston CSO Control Project will virtually eliminate combined sewer overflows and stormwater discharges to the beaches in South Boston.

The project includes four new facilities:

  • a tunnel,
  • an odor control facility,
  • a pump station and
  • a force main

When the project is complete, beach closings will be a very rare occurrence - only about once every 5 years.

WHY THIS PROJECT IS NEEDED

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.

HOW THE PROJECT WILL WORK

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

RELATED PROJECT

The Morrissey Boulevard Storm Drain project is being designed and constructed by the Boston Water and Sewer Commission under agreement with MWRA.

ABOUT THE TUNNEL

The 17-foot diameter, 2.1-mile-long soft ground tunnel will hold 19 million gallons of combined sewer overflows and stormwater, eliminating discharges to the beaches in South Boston. Mining was completed in August 2008. The $148 million project has been constructed by a joint venture of Shank/Balfour Beatty/Barletta.

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PROGRESS PHOTOS
January 10, 2008

Sand Hogs

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Sand hogs head into the tunnel.

Trailing Gear

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The TBM trailing gear in a lined segment of the tunnel. A ventilation system runs along the roof of the tunnel, and tracks have been placed on the tunnel floor.

back end

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A close-up of the TBM's back end and trailing gear.

Back of Cutter Head

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The back of the TBM's cutter head.

Lining In Place

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The liners after placement inside the tunnel.

Liners

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Tunnel liners are stored above the tunnel, where they are covered and kept warm until installation.
More Photos : ARCHIVE
MINING PROGRESS HIGHLIGHTS
08/04/2008 TBM at 10,280 feet -- 572 feet to go!
07/22/2008 TBM at 9,496 feet.
07/15/2008 TBM at 8,968 feet.
06/20/2008 TBM at 7,544 feet.
06/13/2008 TBM at 7,092 feet. TBM has crossed Day Blvd.
06/09/2008 TBM at 6,700 feet.
05/29/2008 TBM at 6,044 feet.
05/19/2008 Mining resumed.
03/28/2008 TBM at 4,544 feet.
03/25/2008 TBM at 4,256 feet
03/24/2008 TBM at 4,104 feet
03/17/2008 TBM at 3,724 feet.
03/11/2008 TBM at 3,352 feet.
03/04/2008 TBM at 2,792 feet.
02/22/2008 TBM at 2,636 feet.
02/22/2008 TBM at 2,328 feet.
02/20/2008 TBM at 2,112 feet.
02/14/2008 TBM at 1,992 feet.
02/08/2008 TBM at 1,744 feet.
First curve begins.
01/24/2008 TBM at 1,016 feet.
12/24/2007 TBM at 369 feet.
11/26/2007 Mining stopped to install trailing gear.

Visit the MWRA CSO Main Page for more information about Combined Sewer Overflows and efforts to control them in Boston, Cambridge, Somerville and Chelsea.

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Updated January 30, 2009