In March, members of the Portland Water Bureau Engineering staff, along with specially trained Maintenance & Construction and Operations staff, inspected the Washington County Supply Line (WCSL) in Southeast Portland. The WCSL is a 60-inch diameter concrete cylinder pipe installed between 1980 and 1984. It is approximately 14-miles long and runs from Powell Butte to Beaverton, Oregon.
Civil Engineer Jeremiah (left) and Civil Engineer Associate Dave (right) were part of the cross-functional team that inspected the Washington County Supply Line.
The purpose of the inspection was to investigate the condition of the pipe. In addition, the crews were inspecting, photographing, and documenting the condition of the interior concrete mortar lining, looking for defects, cracks, and corroded or exposed metal.
Water Operations Mechanic Apprentice Aaron performed mortar lining repairs.
“The inspection refined our understanding of the condition of the pipe and provided us with a platform of good information to use, as well as a benchmark for future assessments,” noted Water Bureau Civil Engineer Jeremiah. “The repairs that were performed may have prevented future unplanned shutdowns and service interruptions to wholesale customers, as well as costs incurred due to an unplanned (probably significantly larger) repair of the pipe itself and damages to its surroundings. The pipe is considered in good condition.”
Engineering Associate Dave performed an internal pipe inspection.
The project team, which included the Water Bureau's Safety and Risk Officer, followed very detailed Oregon Occupational Safety and Health (OSHA) regulations that require stringent safety measures for confined space entry, which include atmospheric monitoring inside the pipe, continuous forced-air ventilation, and having rescue equipment and specially trained rescue personnel on site. Portions of the pipe were dewatered for the pipeline inspection.
The investigations took place while the pipe was shut down in conjunction with the Hannah Mason Pump Station piping work. This internal inspection was a little more than one mile long, out of the 14 total miles of pipe.
The Water Bureau performs inspections and maintenance of our large transmission pipelines during the off-peak season. We are planning to inspect key portions of our major conduits annually over the next three to five years to assess the condition of our transmission/conduit system.