This safety-related work includes constructing a parapet wall on the earthen dam to prevent waves from eroding the dam, and installing a fusegate that will increase the spillway capacity at the reservoir in the event of a catastrophic storm event.

To get ready for this work, the water level in the Foss Reservoir will be lowered about 10ft. The work will also require the removal of some trees along the embankment. The work will be performed in phases and is expected to be completed by the end of next year.

The 130-year old Foss Dam is one of five dams within the MWRA water system being retrofitted to meet new dam safety requirements. Although the dam is not in any danger of imminent failure, the US State issued new regulations in 2006 to ensure that dams classified as “High Hazard” could withstand most any catastrophic event. The classification High Hazard does not refer to condition, but proximity to residents.

The Foss Reservoir is part of the MWRA’s standby water system that would be used as a back-up supply in the event of an emergency.

Foss Dam

Artist’s rendering of new fusegate at Foss Dam. Courtesy MWRA