1. Marilyn’s Report.
2. Bob Response / Elaboration.
1. Marilyn’s Report.
Marilyn Wellons attended the Boston ConCom's hearing on November 17,2010:
The Commission issued a Certificate of Compliance for MWRA work done in Boston on one of three sewer pipes under the river that connect to the Cottage Farm plant by the BU Bridge. The work finished in 2009.
Previously 2 of the 3 pipes led from Cottage Farm to another plant in Boston and ultimately to Deer Island. Flow in the long-unused third pipe was from Boston to Cottage Farm. The work was to reverse that flow, so that all 3 pipes now channel sewage treated at Cottage Farm to the next station in Boston.
It was part of the ongoing court-ordered cleanup of Boston Harbor and the Charles River. Municipalities along the Charles have spent more than $60M so far to separate sanitary and stormwater sewers that have previously been combined (CSOs).
In heavy rains CSOs discharge both stormwater and sewage into, e.g., the Charles River, Alewife Brook, and of course Boston Harbor itself, polluting them. Some CSOs still drain stormwater to Cottage Farm, but as I understand it, the ultimate goal is to have only sanitary sewers drain to it. The project increased Cottage Farm's capacity to treat and pump sewage, to reduce its overflow discharges into the Charles in such storms.
Because the goal is to separate sanitary and stormwater sewers, the MWRA would not have allowed a new connection for stormwater from the BU Bridge to connect to Cottage Farm--unlike the situation at the Cambridge Boat Club, where the sanitary sewer was allowed to tie in to it.
(The MWRA official I spoke with after the Boston ConCom hearing wasn't able to say why the BU Bridge's new stormwater system could not have connected to either Cambridge's or the DCR's own stormwater drains at Brookline Street or along Memorial Drive.)
The increased capacity at Cottage Farm may explain why Lake Pearl Street drained easily through Kathy Podgers's basement into the sanitary sewers, but Cambridge's stormwater system was overwhelmed in the July 10 storm this past summer.
2. Bob Response / Elaboration. Major angle in the sewer separation project.
Thank you Marilyn for the good report.
A few weeks ago, I reported on a decidedly bizarre bike arrangement planned by Cambridge for Western Avenue intersecting Memorial Drive two bridges to the west of the BU Bridge.
During that meeting, the July 12 flooding and the separation of sewers and storm water drains was also discussed. Presentation was by the City Engineer.
The City Engineer specifically stated that a repeat of the flooding of July 12 WOULD NOT be prevented by the ongoing upgrading / separating of the sewer and street drainage system. He stated that the one hour level of downpour was way beyond reasonable capability of the system.
He also added a point that I have never heard before.
He specifically stated that, while the separation will prevent the sewerage system from overflowing into the storm drainage pipes, the opposite is not true. Street drainage will overflow into the sewer pipes if the street drainage system is overloaded.
That overflow of street drainage into the sewer pipes was a major problem on July 12 in a favored establishment of mine on Mass. Ave., The Cellar. This neighborhood bar is in the basement of the building, on the north side of Mass. Ave. They had repeated problems with the sewerage system pumping waste into their establishment.
They controlled it and apparently kept the overflow into a limited part of the bar, but this will happen again under the separation project, and I assume others had similar problems.
