Overview

Ballard was contracted to rehabilitate intake towers at dam and hydrogenation facility. This rehabilitation extends the service life of the intake towers for 50+ years and maintains FERC dam safety requirements.

Scope of Work
Ballard performed extensive and detailed field inspections of the towers to assess structural integrity, existing conditions of the headgates, and the headgate guide connections. Working with their engineering partner, Ballard was responsible for the design of the headgates and their replacement, supporting the client in permit pursuits and assisting with FERC documentation submission.

Innovative Solutions

When conducting onsite operations, ROVs were used to mitigate risk and perform underwater inspections and construction operations, reducing the overall amount of manned underwater interventions by 30%. Both ROV and dive operations were performed at depths up to 200ft.

During the investigation phase, a roller chain came off of one of the gates, leading to the chain laying at the bottom of the intake tower at a depth of 200ft. The Ballard team devised a significantly lower-risk recovery plan to recover the chain using an ROV and creative rigging to avoid a costly mobilization of a deep gas diving operation.

Ballard overcame many challenges on this project, including missing gate documentation and drawings, and the need to develop cost-effective solutions due to embedded gate sealing frames. Ballard used underwater laser scans to confirm measurements to ensure that the gates would seal, and fabricated gates to fit those dimensions.