Quick Thinking Staff’s Solution Keeps Pipeline Repairs on Schedule in San Diego

By on December 7, 2018
San Diego County Water Authority

A leaking valve threatened to derail a 10-day shutdown in mid-November when workers with the San Diego County Water Authority (SDCWA) were scheduled to make repairs inside a dry section of a massive pipe. At issue was a six-foot diameter valve in the Second Aqueduct that was seeping water. The leaking valve loomed as a possible disruption for the time-sensitive operation.

The Second Aqueduct valve was designed to isolate a section of pipeline so the repairs could be made inside a dry section of the pipe. Instead, the leaking valve made it impossible to start the welding work for the relining project in Bonsall and Fallbrook.

The SDCWA coordinates with its 24-member agencies each winter to schedule pipeline shutdowns when water demands are low. This allows work crews to safely conduct routine inspections and make needed repairs.

In order to ensure water agencies and their customers have adequate water supplies while pipes are offline, timing is always critical. The discovery of the mammoth leaking valve had the potential to force major delays in the project as well as the needed water supplies for the community. Plus, the leaking valve threatened to disrupt this year’s refurbishing schedule.

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

The SDCWA’s Operations and Maintenance Department quickly assessed several potential solutions, including using absorbent materials such as rice or oats to soak up excess water. The team quickly determined a strategy to construct temporary dams inside the pipeline and divert the seepage while repairs were made.

This solution required crews to build a dam with 200 sandbags just upstream of the leaking valve and redirect the seeping water into another pipeline and away from the contractor’s workspace. Then, a secondary wooden dam was constructed to collect the trickle of water that was seeping past the sandbags. The solution was successfully deployed in less than 48 hours, allowing the welding project to begin on time.

No water agencies or customers were negatively impacted by this delay. The SDCWA Operations and Maintenance Department is to be saluted for their ingenuity and quick thinking in the face of a potential urgency and near-term emergency.