Back Cove South Storage Facility Combined Sewer Overflow Project
Sebago Technics and its teaming partners were retained by the City of Portland to complete a Business Case Evaluation (BCE) for siting a 3.5-million-gallon CSO storage tank in the Marginal Way area of the lower Bayside area of Portland.
Location
Portland, Maine
Sector
Municipal
Services
- Land Surveying
- Civil Engineering
- Permitting
- Environmental Services
Completed
2025
Project overview
This approach was new to the City of Portland and involved a triple bottom line look at the alternatives addressing the social, economic, environmental, and recreational impacts of the project.
project Details
Complex, multi-year engineering
This is the second storage project in Portland, with the first project also designed by Sebago Technics and its teaming partners. The results of this study were nationally recognized at the WEFTEC conference in 2018 (Virginia).
Following the BCE work, Sebago Technics was retained to develop bridging documents for a design-build approach to the project. This approach involved hydraulic modeling, preliminary sizing of tank components, and geotechnical and environmental screening of the project area. Once the concept was developed, the project team prepared indicative plans, technical specifications, and selection criteria for the design-build (DB) process. The Sebago Technics team served as the owner’s representative through the DB selection process and assembled land use permitting applications including Maine DEP NRPA, USACE, and Local Permit Applications.
In the spring of 2020, the project entered into the construction phase with Sargent and Woodard & Curran selected as the DB contractor. Sebago Technics provided a full-time resident engineer and continued with its teaming partners to serve as the Owner’s Project Manager (OPM) throughout the project construction which was completed in the summer of 2025.
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