The MWRA submitted its Annual Progress Report on Combined Sewer Overflows to federal district court Judge Richard G. Stearns on March 15, 2012, as part of the Boston Harbor cleanup case. The Report describes the progress made by MWRA in cooperation with the Boston Water and Sewer Commission (BWSC), the cities of Cambridge, Chelsea, and Somerville, and the Town of Brookline.
Highlights for 2011 include the completion of the largest of the projects – the $272 million South Boston CSO Storage Tunnel – on May 4, which has virtually eliminated the discharge of both combined sewer overflows and stormwater run-off onto the beaches in South Boston, making them the cleanest urban beaches in the country.
Cambridge began work in 2011 on a $16.1 million project involving innovative green technology with the construction of a new 4-foot by 8-foot box culvert storm drain that will convey separated stormwater to a new 3.4 acre stormwater wetland in the Alewife Brook Reservation.
To date, MWRA has completed 29 of the 35 projects in the $860 million long-term control plan and CSO volume has been reduced by over 2.5 billion gallons a year.
Four of the remaining six projects are well into construction, and the last two projects are scheduled to move into design by April 2012. When the program is completed in 2015, system-wide CSO discharge volume will be reduced from 3.3 billion gallons in 1988 to 0.4 billion gallons, with 93% of the remaining discharge volume receiving treatment at MWRA’s four CSO facilities.