EVENT DETAIL

Back Cove South Storage Facility

The City of Portland, Maine is operating under an Administrative Consent Agreement with the Maine Department of Environmental Protection to abate combined sewer overflows (CSOs). In 1993, the City initiated a Long-Term Control Plan (LTCP) focused on sewer separation projects. When the City updated the LTCP in 2013, green infrastructure and sewer separation were supplemented with the focus on implementing storage facilities, which would capture the first inch of rainfall, store the combined sewer runoff and then send it to the Portland Water District Wastewater Treatment Plant for treatment. The first inch of rainfall is considered the ‘first flush’ and typically contains 80-percent of the storm volume and 90-percent of the pollutants. As part of the 2013 LTCP, the concept of the Back Cove South Storage Facility (BCSSF) project was identified to reduce CSOs into Back Cove by intercepting flow from existing CSO outfalls and sending it to a new 3.5 million-gallon (MG) offline CSO storage facility. The City’s goal is to reduce the annual overflow volume from CSO outfalls 16, 17, and 18 from 150 MG to approximately 18 MG. The project is being constructed as a design-build project. As the design-build lead, Sargent Corporation is managing construction sequencing, methodology, and managing the design team. Woodard & Curran is responsible for the overall project design, including site/civil, environmental, structural, hydraulic and conveyance, mechanical, electrical, plumbing and instrumentation, and controls. The project team also includes Blue Hill Hydraulics, Terracon, GZA and H.B. Fleming, Inc.