Pipeline 5 Upgrades in North San Diego County Halfway Complete

This week, crews are installing a carbon fiber lining inside Pipeline 5 in North San Diego County between Fallbrook and Escondido. The work is essential to maintain the 96-inch pipeline that delivers untreated water from Lake Skinner in southwest Riverside County to the Lower Otay Water Treatment Plant in southern San Diego County.

The work began at the end of March when Pipeline 5 was shut down for the installation of two internal steel bulkheads. The bulkheads allow the rest of the pipeline to stay in service while work is performed in an isolated section.

“Ensuring that water supplies continue to be reliable for all of the region’s 3.3 million residents and businesses is our priority,” said Jim Fisher, director of operations and maintenance at the Water Authority. “We are performing this essential repair to one of our largest pipelines to make sure that there are no interruptions in service to our member agencies.”

Harris & Associates Given Rainbow MWD Design Contract for Pipeline Upgrades

Harris & Associates has been awarded the Rainbow Municipal Water District contract for the design portion of the district’s next pipeline upgrade project.

A 4-0 Rainbow board vote Jan. 28, with Helene Brazier absent, authorized Rainbow general manager Tom Kennedy to execute a contract with Harris & Associates and appropriated the $399,540 Harris & Associates will be paid.

“This is the second phase of our ongoing effort to take care of our highest-priority pipelines,” Kennedy said.

A wooden dam helped allow Operations and Maintenance crews to make repairs to a leaking pipeline valve. Photo: Water Authority Dewatering project

Quick Solution Keeps Pipeline Repairs on Track

When Water Authority crews began dewatering part of the region’s pipeline system for a 10-day shutdown in mid-November, they discovered a leaking valve that threatened to disrupt the time-sensitive operation.

At issue was a six-foot diameter valve in the Second Aqueduct that was designed to isolate a section of pipeline so workers could safely make repairs inside a dry section of the massive pipe. Instead, the valve was seeping water, which made it impossible to start the welding work slated for the relining project in Bonsall and Fallbrook.

The leaking valve was installed in 1980 and is at the end of its useful service life. While valve failure wasn’t an immediate threat, staff had to find a quick solution to avoid delays that could have impacted water deliveries to customers.

Each winter, the Water Authority coordinates with its 24 member agencies to schedule pipeline shutdowns when water demands are low so crews can conduct routine inspections and make repairs. Timing is always critical to ensure water agencies have adequate supplies while pipes are offline.

Strategy devised to allow successful and swift repairs

Water Authority Operations and Maintenance workers made repairs to a leaky pipeline valve. Photo: Water Authority

Crews begin installing an isolation bulkhead after seepage stopped by repairs. Photo: Water Authority

The leaking valve threatened to disrupt this year’s refurbishing plan, forcing the Operations and Maintenance Department to quickly assess several potential solutions, including using absorbent materials such as rice or oats to soak up excess water. The team quickly settled on a strategy to construct temporary dams inside the pipeline and divert the seepage while repairs were made.

First, crews built a dam with 200 sandbags just upstream of the leaking valve, redirecting water into another pipeline and away from the contractor’s workspace. Then, they constructed a secondary wooden dam to collect the trickle of water seeping past the sandbags.

The solution was successfully deployed in less than 48 hours, allowing the welding project to begin on time.