Taking a Deep Dive — Assessing A Critical Ocean Outfall Using High-Tech Underwater Inspection Tools

The Township of Ocean Sewerage Authority (TOSA) was seeking to rehabilitate its 36-inch diameter ocean outfall, which consisted of a 4,000-foot long land-based section and a 2,000-foot long section from a drop manhole on the shore, extending into the ocean. The onshore portion was thought to be constructed of PCCP, and the offshore portion was made of steel. The outfall pipeline was originally constructed between 1966 and 1968, and was reaching 50 years old. TOSA retained Hazen and Sawyer to help assess the physical condition of each section, confirm the materials of construction, and identify the most appropriate repair and/or replacement methods. Hazen teamed with Pure Technologies and utilized PipeDiver™, a state-of-the-art electromagnetic underwater inspection tool that enabled TOSA to identify the types and extent of deterioration and their locations in the outfall, determine the most cost-effective repairs, and thus minimize the duration of outfall downtime for rehabilitation.