Underwater HDPE Pipeline Repair in a Swamp Environment
A 34-inch HDPE line suffered a full separation at a flange in a hard-to-access river swamp. With underwater conditions, barge-only logistics, and a deep excavation, the team needed a repair solution designed for speed, reliability, and real-world field constraints.
Project at a Glance:
- Pipe material: HDPE
- Pipe size: 34-inch
- Pipe depth: 9 ft (to top of pipe)
- Excavation depth: ~15 ft
- Operating pressure: 20 psi
- Age of pipe: 36 years (installed 1990)
- Failure mode: Weld broke at flange; contraction created a complete 8-inch separation
When a critical transmission line fails, the clock starts immediately—but this site added a layer of difficulty that couldn’t be solved with a “typical” repair. The break occurred in a swamp along the Waccamaw River, where access was limited and the work area was completely underwater. Equipment and materials had to be delivered by barge, access had to be cleared, and a temporary roadway built using crane mats. Even excavation required specialized equipment, with an amphibious excavator used to operate in submerged conditions. With the pipe sitting deep and the excavation extending to roughly 15 feet, the repair had to be executed under water while still restoring integrity for 20 psi operation.
JCM Industries is built around a simple promise: deliver repair, connection, and branching solutions that help crews get piping systems back to service—especially when conditions are less than ideal. JCM’s repair fitting portfolio is designed to restore damaged piping systems to their original service capacity across a wide range of diameters, including large transmission mains, and JCM’s technically trained team consults with project managers to help select the right approach for the situation.
In this case, the repair had to address a complete 8-inch separation at a flange on 34-inch HDPE—while accommodating field constraints like underwater work, barge-only delivery, and limited staging space. By aligning the repair strategy to the site realities (deep excavation, submerged conditions, and time-sensitive restoration), JCM helped enable a solution focused on secure sealing, fit-up tolerance, and installation practicality in an environment where “easy access” simply didn’t exist.
Results and Takeaways:
- Service restoration in a high-constraint site: A workable repair plan despite barge-only access and submerged excavation.
- Repair strategy matched to the failure mode: Addressed a circumferential separation created by a broken weld and pipe contraction.
- Field-focused execution: Emphasized installation practicality when equipment mobilization, staging, and visibility were limited.
- Confidence for ongoing operation: Returned the line toward its intended service condition for low-pressure operation.
If you’re facing a challenging repair—large diameter, limited access, submerged work, or nonstandard conditions—JCM’s team can help you evaluate options and identify fittings designed for repair and connection needs. Share your pipe OD, material, pressure, and site constraints, and we’ll help you narrow the right path forward.
