Combined Sewer Overflow to Alewife Brook

Combined Sewer Overflow to Alewife Brook

In accordance with the conditions of the Department of Environmental
Protection's (DEP) Alewife Brook/Upper Mystic River Variance we are
hereby notifying you that a Combined Sewer Overflow (CSO) occurred
at CAM401B on July 28, 2014 and discharged into the Alewife Brook.
The Variance approved workplan requires the Cambridge Department of
Public Works (DPW) to notify local health agents, DEP, EPA and MRWA
within 24 hours of when a CSO event occurs. It was determined that
401B was the most active outfall and would be the most suitable
indicator of CSO activity along the Alewife Brook. This notification
does not reflect the absence of any activation at other sites.
Rather, the notice is intended to be confirmation to users of the
resource that untreated sewage discharges to the Brook/River have
occurred.

The water quality in Alewife Brook is often impaired due to
bacterial and other pollutants from a number of sources, including
stormwater runoff, CSOs and cross connections between sanitary
sewers and stormwater drains. Water quality in the brook during both
wet and dry weather generally fails to meet state bacteria standards
for fishing and swimming. Contaminant sources originate in the
watershed communities of Belmont, Arlington, Cambridge and
Somerville, all of which are undertaking programs to identify and
control the sources of pollution to the brook.

Portions of Cambridge and Somerville are served by combined
stormwater and sanitary sewer systems, common in older cities. There
are eight CSO outfalls on Alewife Brook (see the attached map for
locations) which discharge untreated CSO (a mixture of wastewater
and stormwater) during moderate and heavy rainfall to relieve the
system and prevent sewer backups into homes, businesses, and
streets. In addition, bordering communities also have separate
drainage pipes that collect stormwater runoff and carry it to the
brook. Discharges from CSOs and from separate stormwater pipes
include bacteria and other pathogens, oxygen-demanding pollutants,
solids and other contaminants. Public health officials recommend
avoiding contact with the brook during and for 48 hours following
rain storms, as there may be increased health risks during these
periods. Contact with floodwaters should also be avoided as they may
contain similar contaminants and pose associated health risks. Clean
up information following a flood is available on the MA Department
of Environmental Protection web site at:

http://www.mass.gov/dep/floodcleanup.htm

For real-time water data at Fresh Pond Reservoir, you can view the
United States Geological Survey National Water System website at:

http://waterdata.usgs.gov/ma/nwis

Please contact Catherine Daly Woodbury at 617-349-4818 or James
Wilcox at 617-349-6426 if you have any questions.