BANGOR, ME – April 2025 – The Associated General Contractors of Maine (AGC Maine) is proud to name N.S. Giles’ Back Cover South Storage Project as the Building Division Award Winner for the 2025 Build Maine Awards.
The Back Cove South Storage Facility demonstrates how infrastructure improvements can contribute to both the surrounding community and environment. Built by N.S. Giles, the project also represents the largest contact, rebar, and poured concrete project in the company’s history. To complete this project, N.S. Giles placed over 1,200 tons of rebar and poured over 18,000 cubic yards of concrete. Designed to improve the City’s wastewater infrastructure and the environmental health of Back Cove and Casco Bay, the Storage Facility collects the first inch of stormwater in the watershed area and holds it for later treatment at the wastewater treatment plant. With four underground concrete tanks that have a capacity of 3.5 million gallons, the project has lowered the Combined Sewer Overflow (CSO) by 40%, a significant reduction. Additionally, the facility helps reduce costs for the City of Portland while also resulting in a cleaner bay. The Back Cove South Storage Facility will serve as a lasting testament to what can be accomplished through partnership, perseverance, and a steadfast commitment to safety.
CONTRIBUTION TO COMMUNITY
This project exemplifies a successful integration of environmental protection and community enhancement, contributing to a healthier ecosystem and improved quality of life for Portland residents. By managing stormwater more effectively and mitigating flood risks, the facility also supports the community’s overall resilience against climate change impacts.
Construction took place next to the Back Cove Trail, one of the most popular trails in Portland for running, biking, and walking. Recognizing the community’s need for this space, N.S. Giles maintained public access to it throughout construction. Beyond creating storage tanks for sewer overflow, the project also involved restoring and elevating the Preble Street playing fields. Raising the elevation enhances their resilience to tidal flooding, ensuring the ability for community sports and events in the future.
INNOVATION
N.S. Giles participated in the early stages of the design process for the Storage Facility. This allowed them to provide valuable input up front, resulting in a reduction of construction joints, which enhances the overall durability and longevity of the facility. The storage tanks were built to withstand extreme hydrostatic pressure, requiring meticulous formwork installation. The team utilized DOKA form systems to deliver high- quality, efficient formwork solutions tailored to the project’s unique requirements. Additionally, N.S. Giles executed numerous 1,000+ yard concrete placements, often running multiple pump trucks simultaneously to maintain productivity and quality. Through the use of advanced curing methods and temperature control techniques, N.S. Giles was able to successfully navigate winter concrete as well. These innovative methods not only helped the team complete the project on time but also set a new standard for excellence in the industry.
ENVIRONMENT
The Combined Sewage Overflow (CSO) that is discharged into Casco Bay each year is a significant environmental problem in the Portland area. The Back Cove South Storage Facility was designed to capture and store up to 3.5 million gallons of combined stormwater and sewage during heavy rainfall events. This prevents untreated wastewater from discharging into Back Cove and Portland Harbor, thereby reducing CSOs, improving water quality, and protecting marine ecosystems. By intercepting the initial flow of stormwater – which often contains the highest concentration of pollutants – the facility ensures that contaminants are treated before being released into the environment. This proactive approach significantly reduces the pollutant load entering Casco Bay.
Additionally, the soil excavated during the project was repurposed to elevate the surrounding Back Cove Park, enhancing flood resiliency and restoring recreational spaces such as the Preble Street playing fields.
Maintaining environmental compliance throughout the project was a priority as well, and N.S. Giles collaborated with multiple stakeholders to meet this goal.
CHALLENGES & SAFETY
The facility was constructed adjacent to Casco Bay and Interstate 295, a challenging logistical location. Maintaining the public’s safety and convenience was a priority and N.S. Giles strived for minimal disruption to the surrounding community over the four-year project duration. The crews were required to work through site flooding events, and always diligently maintained the highest safety and quality standards.
The COVID-19 pandemic presented unprecedented challenges to the construction industry, which N.S. Giles navigated during the height of the project. The safety of their workforce remained a top priority, and they implemented rigorous health and safety protocols to comply with state and federal guidelines.
In addition to the pandemic, the ongoing labor shortages required the N.S. Giles team to adapt quickly, optimize crew schedules, and maximize productivity without ever compromising safety or quality. With a dedicated workforce and commitment to compliance, N.S. Giles was able to maintain project momentum.
Safety was at the forefront of every decision made throughout the project. N.S. Giles had to work around both numerous pieces of heavy equipment and the public, all while maintaining strict safety protocols. The team successfully navigated a range of safety challenges, including working at heights, operating multiple cranes and pump trucks simultaneously, and managing confined spaces within the underground tanks.
Additionally, they partnered with the H2B visa program, integrating workers from Jamaica and Mexico into the team. This required comprehensive safety training and communication to ensure every team member understood safety protocols.
N.S. Giles was able to complete over 60,000 safe man hours without a single injury. The team also passed an OSHA inspection with zero violations, a testament to their diligence and preparation. The implementation of confined space entry procedures, fall protection systems, and daily safety briefings played a vital role in maintaining this injury-free record.
Project Title: Back Cove South Storage Facility
Owner: City of Portland
Construction Manager: N.S. Giles
General Contractor: Sargent Corporation
Engineers: Sebago Technics and Woodard & Curran
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About AGC Maine
Chartered in 1951, AGC Maine is headquartered in Augusta and has members statewide that include contractors, subcontractors, service providers, suppliers, and developers. The Mission of AGC Maine is to advance and support Maine’s construction industry by promoting the highest standards of craftsmanship, safety, and sustainability, while empowering our members through advocacy, education, and collaborative partnerships.
