MWRA, High Level Sewer

Roslindale, MA


Massachusetts Water Resource Authority



The High Level Sewer (HLS) is a masonry conduit built around 1901. Following a large rainstorm, the HLS developed internal pressure that caused water to overflow through the manholes and flood parts of the Roslindale neighborhood. The manholes were bolted down to prevent future flooding. A couple years later, during a heavy rain storm, the HLS was pressurized again, resulting in failures of manholes, cracking of the masonry conduit, movement and cracking at bends in the sewer line, and significant leakage. SGH was retained to perform an emergency condition assessment, evaluate risk of pressurization during future storm events, and develop a repair program.