Director, Civil Engineering Kuna Engineering, Alaska, United States
Abstract Submission: Between 2008-2017, a new water and sewer system was constructed in Buckland, Alaska. Buckland is a remote Native Alaskan village of 510 residents located just south of the Arctic Circle accessible only by boat or airplane. Buckland’s soils consist of ice-rich permafrost made of flood plain deposits. Seasonal thaw was observed between two and four feet in undisturbed areas. Ice lenses exceeding six feet have been found. This project included the entire system from water source through wastewater treatment. The project was contracted as a design-build with force account construction. As the project neared completion, there was a ten to twenty percent annual failure rate of sewer services. In at least one case, a single sewer service was replaced three times in three years. In 2017, the project funding agency requested a third-party review of the project to determine failure mode, recommend repairs, and provide lessons learned for future projects. The review team was provided access to design and construction documents. In addition, the team spent five days in Buckland investigating issues, interviewing crews, and observing repairs and new construction. Due to Buckland’s difficult soil conditions, it was initially assumed that permafrost was unstable and thawing rapidly resulting in pipe separation. The investigation revealed a variety of issues related to design, construction, and project management as key to the failures, unrelated to the poor soil conditions. It also provided confirmation of certain standard design elements. In 2023, additional investigations were done by the same team on sewer main failures. This investigation came to similar conclusion as the 2017 study.
Learning Objectives/Expected Outcome (Optional) : The intent is to educate water professionals on the design and construction issues of water and wastewater utilities in remote, arctic communities. The extreme conditions of these utilities show failure points with typical designs and construction techniques. The lessons learned can help improve constructability and sustainability of future projects.
