Mystic CSO Map

Combined Sewer Overflows (CSO):

• MyRWA Comments on Cambridge CSOs

• MyRWA Comment Letter on Final Variance Report 10/31/04

• EPA To Notify Public of Sewage Spills

CSO Information

MWRA's 2003 CSO Program Annual Report, Massachusetts Water Resources Authority

Joint MWRA/Cambridge/Somerville Press Release on Alewife CSO Project, April 2004

Lefkovitz L, Dahlen D, Hunt CD, Ellis BD. 2000. 1998 CSO sediment study synthesis report. Boston: Massachusetts Water Resources Authority. Report ENQUAD 1999-12. 68 p.

Alewife Study Group keeps tabs on the ongoing plans for Cambridge and Somerville CSOs.

An e-mail-based newsletter, the Stormwater Runoff Water Quality Science/Engineering Newsletter, is available. Information can be found at http://www.gfredlee.com.

Download and read 'Eight simple steps to clean water', focusing on polluted stormwater.

Read EOEA press release on CSO study in the Mystic and Alewife. (11/98)

Officials say key to keeping waterways clean is containing sewage overflows during floods (8/99)

For more information, check out the new CSO and SSO fact sheets at www.cwn.org under "Wet Weather".

What is a Combined Sewer Overflow?

From the Massachusetts Water Resources Authority: "While modern systems generally handle rainwater and sewage from homes and businesses in different pipes, older systems in Boston, Cambridge, Chelsea and Somerville have 'combined' sewers that carry both flows together. During normal conditions the flows can generally be delivered to treatment plants. During heavy rains, these systems become overloaded. Built-in overflows (called combined sewer overflows or CSOs) must then act as release valves by letting excess flows leave the system upstream of sewage treatment plants, into the nearest body of water. This prevents sewer backups into homes and onto area streets but it does so at considerable cost to local water quality."

During the Spring 2001 floods, there were many sewer overflows. For example:

• According to a Woburn city engineer, approximately 50 million gallons of raw sewage spilled into Horn Pond during the recent flooding. The city had to close down its municipal wells in the area as a result.
  
• There was extensive flooding on the Kraft plant property (also in Woburn) from both Sweetwater Brook and the Aberjona. One of the three MWRA reliever pipes flowing under their facility overflowed, causing sewage to enter their power generation building. They were able to continue with production by buying power from an outside source.

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